PRACTICAL COURSE
HOROLOGY
From
the collection of the
^
m
Prelinger ^ D
Jjibrary t
P
San Francisco, California 2008
A PRACTICAL COURSE
IN
HOROLOGY
A PRACTICAL COURSE IN
HOROLOGY By
HAROLD C KELLY
Head, Department of Horology Southwestern Institute of Technology Weatherford, Oklahoma
THE MANUAL ARTS PRESS PEORIA, ILLINOIS
Copyright, 1944
THE MANUAL ARTS PRESS
No
part of this book
may
be reproduced in any
form without permission of the copyright owner 34KS5
PRINTED IN THE UNITED STATES OF AMERICA
CONTENTS
"TIME'' Poem, by Laurens L, Simpson
.
.
Preface
7
9
PART
I:
GENERAL PRINCIPLES
Chapter
ONE.
Wheel Work
13
TWO.
Gearing
32
The Lever Escapement
39
THREE. FOUR.
The Controlling Mechanism
PART
II:
...
52
PRACTICAL REPAIRING
ONE.
Train Problems
62
TWO.
Jeweling
6^
THREE. FOUR. FIVE. SIX.
SEVEN.
Making a Balance
Staff
72>
Pivoting
85
Fitting Balance Springs
88
Escapement Adjusting
100
Cleaning and Oiling
124
5
PART
III:
ADJUSTING
ONE.
Preliminary Notes on Adjusting
TWO.
Position Adjusting
.
.
128
140
THREE.
Adjustment
to Isochronism
.
.
.
.150
FOUR.
Adjustment
to Temperature.
.
.
.156
.
.
.
FIVE.
Practical
Work of Adjusting
159
Glossary of Terms
173
Bibliography
182
Index
185
6
TIME BY Laurens L. Simpson (written to accompany the gift of a watch)
• /
am
I
come
time. to
give thee life
Twenty-four hours of every day, All this to every man. I tick
tick.
I sound in peace, and strife,
In
sleep, in
work and
play.
Forever, on and on. I never change
To good and had alike. The rich, the brave, the All use
I
am
To
me
as they may.
gold
who who do
those
Lead,
The
free
will; to others
not see
benefit of industry.
am power. Weak to strong, coward
I
Man
grows as I move
Or not,
to brave,
on,
as will he may.
(continued next page) 7
I
am fame
To
those
Who
whose
shine with
light is bright, all their
might,
Pure, through day and night. I
am
To
happiness
those
Who
who
serve and give,
help the weak, mxike
The unknown, and
Now
live.
or never
Equal chance I give
My
known
days
to
use or
lose.
Here once then gone
8
to all,
forever.
PREFACE The
art of horology unquestionably ranks among the
most wonderful of the mechanical at the diminutive size of the
arts.
One can
only marvel
modern wrist watch and the
accuracy of the machines by which the duplicate parts are
made. Production and improved manufacturing methods have also changed the repairman's approach to horology. licate parts are available, so the horologist is
upon
to
make a
part.
However,
Dup-
seldom called
since the sizes of watches
have been reduced, new tools and improved methods are essential to
good workmanship.
skill in fitting staffs to small,
One must
develop a greater
uncut balance wheels, in adjust-
ing small escapements, and in handling the new, alloyed balance springs.
The purpose
of this book
is
to present the fundamentals
of horology, both in theory and practice.
Part 1 deals with
wheel work and gearing, which involve the work of calculating the number of teeth of missing wheels and pinions and in determining their proper diameters.
ment design and an
Principles of escape-
analysis of the balance
given considerable space.
and spring are
Part 2 treats repair methods, in
which the making of a balance
staff
and the adjustment of
the escapement are given more than the usual space allotted
ments to
Part 3
is
concerned with the adjust-
position, isochronism,
and temperature, factors that
to these subjects.
A PRACTICAL COURSE IN HOROLOGY
10
may
be called the finishing touches of the horological pro-
fession.
The author is indebted to T. J. Wilkinson and C. E. DeLong for the reading of parts of the manuscript and for helpful suggestions. The chapter on wheel work is based on a system by Jules Grossman, ical
late director of the horolog-
school of Locle.
It is
hoped that
this
work
will contribute
some small part
toward the development of a generation of capable and well equipped horologists.
HAROLD
C.
KELLY
PART
1
GENERAL PRINCIPLES
Parti
CHAPTER ONE
Wheel Work Terminology
Wheel work
is
the basis for the construction of
struments for the registering of time.
one of the
earliest
Even the
these early clocks as well as those of the filed
clepsydra,
forms of a clock, which operated by the
dripping of water, involved the use of wheels.
were
all in-
first
The wheels
of
pendulum clocks
out by hand and although the workmanship on some
of the later creations was quite skillfully executed, they were, of course, very crude as compared with the machine-made
wheels of modern clocks and watches.
Since wheels are
fundamental to the construction of watches,
we have
decided
that this opening chapter shall be given over to the consideration of wheels as they apply to the science of horology.
low are
Be-
listed several definitions relative to the subject:
Wheel: any circular which teeth may be cut
piece of metal on the periphery of
of various forms and numbers.
Pinion: the smaller wheel with teeth called leaves, working in connection with a larger wheel.
Train: a combination of two or more wheels and pinions, geared together and transmitting power from one part of a
mechanism
to another. 13
A PRACTICAL COURSE IN HOROLOGY
14
a circular box of metal for the reception of the
Barrel:
main
spring.
Balance: the vibratory wheel, which, the balance spring, controls the
Balance spring: a
movement of
fine, coiled wire,
with
in connection
the hands.
one end of which
is
attached by a collet to the balance staff and the other end to
some stationary part of the watch through the medium of a piece called a stud.
Beat: resulting
one vibration of the balance and balance spring
from an impulse received by means of an escape-
ment.
Escapement:
includes
those
parts
a watch which
of
change the circular force of the escape wheel into the vibratory motion of the balance. Pallets:
that part of
an escapement which receives im-
pulse from the escape wheel and by
impulse to the balance.
means of a
lever delivers
This term includes the
pallet
arms
and jewels. Receiving pallet:
that pallet stone over
which a tooth
of the escape wheel slides in order to enter between the pallet stones.
Discharging pallet: that pallet stone over which a tooth of the escape wheel slides in order to leave from between the pallets.
Lock: on a
the overlapping contact of an escape wheel tooth
pallet stone's locking face.
Watch Trains Since the motive force stored In the main spring of a
watch does not
act directly
on the balance,
it is
by necessity
:
WHEEL WORK
15
transmitted by a system of toothed wheels and pinions. This
system of wheels and pinions, commonly called a
train, is a
mathematical assemblage of mobiles, and anyone
scientific,
who becomes familiar with the principles much satisfaction from such knowledge.
involved derives
we have two trains, the main train and the The main train changes a slow motion into a
In watches dial
train.
fast
one with the particular purpose of causing the wheel
make one turn in the same escapement makes a required number of beats.
that carries the minute
time that the
The
dial train,
hand
to
on the other hand, changes a
fast
motion
Into a slow one for the purpose of governing the distance the
hour hand travels to one turn of the minute hand.
The Main Train Calculating the to obtain the is
geared,
we
number
of turns of a pinion.
number of turns of a pinion divide the
into
In order
which a wheel
Q
num-
ber of teeth in the wheel by the
number of
leaves in the pinion.
Suppose, for example, a wheel of 72 teeth gears into a pinion
of 12 leaves.
wheel as
B
Designating the
and the pinion into
which the wheel gears as Figure
1,
c,
the formula for the
problem reads as follows
B
— = number of turns of the
pinion.
Figure 1
:
:
:
A PRACTICAL COURSE IN HOROLOGY
16
Substituting
B — by
their numerical values
we have
c
72 — = 6 turns of the pinion to one of the wheel. 12
Calculating the
Most watch
number
of turns of a complete train.
trains contain five wheels, as
shown
in
Figure
2.
These include the main-spring barrel and the escape wheel,
and
all five
mobiles are usually
named as
B = barrel or first wheel C = center or second wheel
T = third wheel F=
fourth wheel
E = escape wheel The
pinions are as follows
= center or second pinion = third pinion = fourth pinion e = escape pinion
c t
f
Figure
2.
Main
train.
follows
WHEEL WORK It will first
17
be noted that the second pinion
pinion, but for convenience
as the wheel of which
it
is
it
is
is
in reality the
given the same
name
a part and referred to as the
center or second pinion.
As an example
of a
modern
train
we
shall select the
ber of teeth of wheels and leaves of pinions as
(Remember, the
barrel,
center,
wheels are indicated by the capital
and the
center, third, fourth
letters c, t,f
and
B
72
C
_80_
T
75
1 F
_
num-
shown below.
fourth and escape
third, letters
B, C, T,
F
and E,
and escape pinions by the small
e.)
^
lo"^ 80
Multiplying the numbers
6,
get 3,600, which represents the
wheel to one of the
8,
7j^, and 10 together
number
we
of turns of the escape
barrel.
Dividing 3,600 by 6 (turns of center wheel to one of the
we
barrel)
made by
number (600)
represents the turns
the escape wheel in one hour, since the center wheel
carries the
hour.
get 600. This
minute hand and, of course, makes one turn in an
Henceforth
all
calculations will be based
of the center wheel, and on this basis
we submit
on one turn the follow-
ing formula, in which, as above, the capital letters C, T, indicate the wheels pinions.
and the small
letters
t,
f,
F
e indicate the
:
:
:
A PRACTICAL COURSE IN HOROLOGY
18
CTF
= 80 X 75 X 80 = 600 turns of the escape wheel. 10
tfe
X
10
X
The fourth wheel seconds
8 in
watches designed to register
all
so constructed that a second
is
hand
is fitted
to the
extremity of a long pivot extending through a hole in the follows, therefore, that according to the accepted
It
dial.
plan for the division of time, the fourth wheel must
make
60 turns to one of the center wheel. Therefore
CT
= 80 X 75 = 60 turns of the fourth wheel. 10
tf
However,
X
10
this is not necessary in
no second hand, and
in
many
makes more than 60 turns shall
soon
to
watches where there
is
wrist watches the fourth wheel
one of the center wheel, as we
see.
Calculating the
number
The escape wheel in and delivers twice as many
of beats.
most watches contains 15 teeth
impulses to the balance, since each tooth delivers two impulses, first to the receiving pallet pallet.
Letting
E
and
later to the discharging
indicate the escape wheel
and
e the escape
pinion, the formula reads
CTF2E
= number of beats per ^ hour.
tfe
Substituting the numerical values
we have
80X75X80X2X15 10 X 10 X 8
= 18,000 beats per hour.
Fast and slow trains.
Not
per hour.
Some
watches make 18,000 beats
of the older watches
beats per hour, whereas
make
all
make 16,200 and 14,400
some newer American wrist watches
19,800 and 21,600 beats per hour.
There are other
trains of varying beats per hour, particularly
among
those
:
WHEEL WORK
19
Below are shown two examples of
of Swiss manufacture.
slow trains
X 72 X 2 X 10X10X8 80 X 75 X 80 X 2 X 80
X
75
15
== 16,200 beats per hour. 15
10X10X10 As
= 14,400 beats per hour.
already stated, watches without second hands
may have
any system of mobiles wherein the fourth wheel register seconds. all
Below are
will not
listed three trains of this type,
of which are fast trains used in small wrist watches.
54X 50X48X2 X
15
18,000 beats per hour.
6X6X6 64X66X60X2X15 =
8X8X6
42
X 42 X
35
X
35
X2X
19,800 beats per hour.
12
7X7X7X7 The
last train listed is
= 21,600 beats per hour.
unique in that the train has 6 wheels
with an escape wheel containing 12 teeth.
Comments on the fast trains. In the preceding paragraphs we discussed the slow and fast trains that have been in general use at various periods. We shall now consider further the
modern
fast trains
used to some extent
in
very
small wrist watches.
The watch
train
making 18,000
accepted as a sort of standard for
beats per hour has been
many
years.
However,
very small wrist watches making beats of various numbers per hour in excess of this figure are becoming more in evi-
dence and the increased use of such trains would lead one to inquire into the reason for their popularity.
:
A PRACTICAL COURSE IN
20
The reason
HOROLOGY when
the fact that 18,000-beat trains,
lies in
applied to very small wrist watches, have a tendency to set
on the locking. This
is
due to the fact that a
light balance
and a weak balance spring have not the necessary force to effect a satisfactory
come
unlocking of the escapement.
this fault of setting
on the locking,
it
reduce the drop lock to the very minimum. it
is
is
To
over-
necessary to
However,
since
expect the same precision of adjustment in
difficult to
small watches as offer a solution.
possible in larger watches, the fast trains
is
The
due to two factors:
make the unlocking easier more rapid motion of the bal-
fast trains
(1) the
ance and (2) the increased strength of the balance spring.
way
In this
the
new
fast trains permit a greater tolerance
with regard to the extent of the lock, resulting in a reduced tendency to set on the locking.
There
is
Better timekeeping results.
another point in favor of the
new
Every horologist has observed how often the
fast trains. coils of the
balance spring get caught in the regulator pins or get badly tangled due to a severe fast train
We
The
stronger springs fitted to
to eliminate the difficulty or, at
frequent occurrence.
Calculating the mobiles.
much
watches do
least, to lessen its
jolt.
number
now wish
and leaves of missing determine the number of teeth
of teeth
to
of wheels and leaves of pinions that are missing.
Let
F
indicate the missing fourth wheel of the following train
80
X
———
XFX2X 10X10X8 75
^
15 = 18,000
= 18,000 F = 80
225F
According to the above solution the fourth wheel contains 80
teeth.
1
:
:
WHEEL WORK In the next problem, the third pinion
21
is
mission. Letting
t
indicate the mission pinion, the equation reads as follows
—X
—=
2 X X 80 X ——t X 10 X 8
80
75
180,000
15
18,000
= 18,000
t
180,000= 18,000 18,000 t
=
1
180,000
== 10 leaves of the third pinion
Let us suppose that the complete fourth wheel and pinion of a wrist watch are missing in which is
The equation reads
the pinion.
54
XFX2X 6xf X6
X
50
2,250
F
-
15
F
is
the wheel and /
:
= 18,000
= 18,000
f
F
18,000
8
f
2,250
1
The
result
times as
many
nating / by
shows that the fourth wheel should have 8 teeth as the fourth pinion has leaves.
6, 7, 8,
or 10 leaves,
we may
Desig-
obtain any of the
following solutions.
48 "6"
64
80
'7 '¥
'To
56
Any
of the solutions given above
may
be used; however,
judging from the numbers of teeth and leaves of the train as
a whole, the most suitable numbers would be
F
48
:
:
A PRACTICAL COURSE IN HOROLOGY
22
There are times when the
ratios
For example we wish
numerator.
come out with a
fractional
to determine the
number
of teeth and leaves of a missing third wheel and pinion in
T
which
the wheel and
is
t is
the pinion.
-—X T X 48 X 2 X 15 = 18,000
54
tX6x6
2,160T
= 18,000
t
T
18,000
syi
2,160
"T"
T^ The
only numbers that
number of
fractional
may
be tried without producing a
teeth are
75 50 — and —
9
6
In this example the most suitable numbers would be
T
50
T~6~ There are other times when we arrive
at the
mediately, as in the case of determining the teeth of the escape wheel, E,
pinion,
90
answer im-
number
of the
and the leaves of the escape
e.
X 80 X 2E = 18.000 12 X 10 X e
X
80
9,600E
= 18,000
e
E
18,000
15
e
9,600
8
The answer shows
that the escape wheel contains 15 teeth
and the escape pinion 8
leaves.
:
:
WHEEL WORK new
Calculating a
number of
teeth for the wheels
pinions of a
new
small baguette
now wish
to determine the
and number of leaves for the
Let us suppose the watch
train.
is
to be a
making 21,600 beats per hour. Using the same
before to indicate the wheels and pinions the
as
letters
We
train.
23
formula reads as follows
CTF2E
= 21,600
tfe
We
may
number
decide in advance the
of leaves for the
number of teeth for the escape wheel. For the pinions t, f, and e we shall use 6 leaves each. The escape wheel will have 1 5 teeth. The equation now reads pinions and the
CTF2X
15
21,600
6X6X6 CTF =
21,000
X6X6X6 2X15
CTF= 155,520 CTF
The combined product of obtain the quantities desired,
number
into its
it
is
prime factors and
is
155,520.
In order to
necessary to resolve this to
three groups which will represent the
form these factors
numbers
into
for the teeth
of the wheels C, T, and F.
2)155520
2)
9720
3)
2) 777Q()
2)
4860
3)
2) 38880
2)
2430
2) 19440
3)
1215
405
5
Factoring,
we
find that
CTF
=
155,520
= 2^ X
3^
X
5.
:
:
A PRACTICAL COURSE IN
24
These factors may be formed binations, but the train
HOROLOGY com-
into groups of various
most suitable arrangement for a watch
would be as follows
C=
5X3X22 = 60 T = 33 X 2 = 54 F = 3 X 2^ = 48 Thus we show 60
X
54
X
the complete train.
48
X2X
15
6X6X6
= 21,600 beats per hour.
The Barrel and The
and
barrel
its
design of a watch. pinion must
Mainspring
mainspring are important factors
The
show a
Its
ratio
in the
between the barrel and center
definite relationship to the length
and
strength of the mainspring and must be determined with
mathematical exactness factorily
if
the watch
is
to
perform
satis-
and run a required number of hours.
Calculating the
number
of
hours a given watch will run.
In order to determine the number of hours a watch will run
we must to
first
find the
number of turns of the
one of the barrel. Letting
B
center pinion, the formula reads
center wheel
indicate the barrel
and
c the
:
B — = number of turns of center wheel
to one of the barrel.
c
Using a numerical example, we have
84 — = ^7 turns of center wheel. 12
Knowing it
that the center wheel
makes one turn
in
an hour,
follows that the barrel makes one turn in 7 hours.
Next
:
:
WHEEL WORK we must determine pletely
wind the
the
spring.
number of turns necessary to comA trial has shown that it takes 5^
turns to wind the spring.
run
will
is
25
The number
of hours the watch
found by multiplying 7 by 5^, thus
7X5^== 3Sj4 hours the watch will run. The mainspring should run hours; 36 to 40 hours
is
the watch not less than 32
better; in fact,
some of the
finest
watches will run 45 hours and more. Calculating the correct thickness of the mainspring.
We
experience no difficulty in fitting mainsprings to standard
makes of watches, for as catalogued
all
we have
to do
is
to select the spring
and graded by the particular manufacturer.
There are times, however, when an old watch or one of unfamiliar
make needs a new
the old spring
is
spring and,
not the correct one,
if
we
we need
suspect that
to apply a bit
of mathematical calculation to determine the correct thick-
ness of the spring.
In such cases the following method
is
suggested 1.
Divide the teeth of the barrel by the leaves of the center
pinion in order to determine the
one turn of the 2.
number of hours taken
for
barrel.
Determine the number of turns necessary to wind the
spring by dividing 36 (hours of running) by the
number of
hours consumed in one turn of the barrel. 3.
by
Measure the
inside diameter of the barrel
and divide
12.5. 4.
Divide the above quotient by the number of turns neces-
sary to wind the spring.
The
result
is
the thickness of the
spring.
Suppose for example that the
barrel, B, has
78 teeth and
:
A PRACTICAL COURSE IN HOROLOGY
26
the center pinion, the barrel 1.
is
c,
6.5
c
36
The
inside diameter of
12 millimeters.
—=— = 12
2.
has 12 leaves.
X
1
=6.5
hours,
= 5.5 turns to wind sprmg.
6.5
12
= .96
3.
12.5 •96 4.
= .17 mm., thickness of... the spnng.
5.5 It
should be understood that the answers are only ap-
proximate. In some cases, as in a a weaker spring
may
fine,
21- or 23- jewel watch,
be needed, whereas a 7- jewel watch
may
require a stronger spring.
Calculating the correct length of the mainspring. The proper length of the spring need not be calculated in so inches.
we may
Instead,
state that the spring should
many
occupy
one half of the area between the inside wall of the barrel
and the periphery of the arbor. If the spring does length
this,
the
is correct.
Observe that we say area and not space. The term space
would lead one
to infer that radial
measurements are
in-
tended, which would be incorrect, inasmuch as a spring
wound up would occupy more spring run down.
radial space than that of a
Thus, the statement often found in older
books on horology to the
effect that
we
allow one third of
the space for the arbor, one third for the space, and one third for the spring
is
slightly in error
a few coils too long.
The
correct rule should read
and indicative of a spring
WHEEL WORK One
third of the space is occupied by the barrel arbor
one half of the remaining area This
27
is clearly
shown
in
is
covered by the spring.
Figure
that the radial distance occupied
Figure
3.
It will
3.
by the spring
However
is less
the area of both spring
space are equal and
it
remains the same under
whether the spring
is
wound
Now
be observed than
Barrel showing correct space for mainspring.
that given to space.
or completely
and
let
all
and
conditions,
completely, partially
let
down,
down.
wind the spring
in the barrel
and
if
the spring oc-
more than one half of the area, break off the outer end and rewind in the barrel. When the correct area is cupies
determined the hook
is affixed.
A
contains from eleven to thirteen
spring of the proper length coils.
More than
the re-
:
A PRACTICAL COURSE IN HOROLOGY
28
quired number of coils only tends to increase friction and shorten the number of hours of running of the watch.
The Dial Train The cannon pinion, minute wheel, minute pinion, and hour wheel make up the dial train. Referring to Figure 4, the
Figure dial train is
4.
Dial train.
arranged as follows. The cannon pinion,
into the minute wheel,
the minute wheel
This latter wheel
is
M. The minute
pinion,
c,
gears
m, to which
attached, gears into the hour wheel,
fits
freely over the
cannon pinion.
H.
The
minute hand, of course, makes 12 turns to one of the hour
The formula
hand.
for the dial train, therefore, reads as
follows
HM =
12
cm number of teeth of pinions of a new dial
Let us suppose
we wish
to determine the
of wheels and the
number
of leaves
train.
We
shall decide
on 12 leaves for the cannon pinion,
c,
:
:
:
:
WHEEL WORK and 10 leaves for the minute
pinion,
29
m. Letting
H indicate
M the minute wheel, the equation reads HM = HM 12 cm 12 X 10 HM=12X 12X 10; HM = 1,440
the hour wheel
and
Factoring in the manner as heretofore explained,
we
find
that:
HM = 25 X
32
X
5
Combining these factors
to
form two groups representing
H and M we have H = 23 X 5 = 40; M = 22 X 32 = 36
the wheels
Thus the complete
train reads as follows
HM = 40 —X-- 36 cm
12
— =12 X 10
Various types of into three types:
minute wheel
to the
M_36_
(2)
may be grouped
the reverse, and
In the regular the ratio of cannon pinion
is
hour wheel
Dial trains
the regular,
(1)
(3) the irregular. to
dial trains.
and the
3 to
1
4 to
1.
is
ratio of the
minute pinion
H_l^_4
"c"~T2~
'
m"~10"""
In the reverse the ratio of the cannon pinion to minute
wheel
is
wheel
is
4
to
3 to
as
ratio of the
minute pinion to hour
1.
M_32_ T~'%~ The
and the
1
H_?l_^ '
m~"8"~
irregular does not belong to either of the above types,
shown by the following example
HM cm
35X48 14
X
10
48X26 13
X
8
32X45 12
X
10
12
—
:
A PRACTICAL COURSE IN HOROLOGY
30
Thus
the dial train
may
be formed by working out various
combinations, the only requirement being that the combined
The most
ratios equal 12.
4
to
1
used, however,
is
the 3 to
1
type referred to as the regular.
Calculating the teeth and leaves of missing mobiles. Let us suppose that the cannon pinion
is
missing from the
following train in which c represents the cannon pinion
54X32
CX12
= 12
i^ = 12 c
= 12c 12c = 144 c = 12
144
We
leaves of the cannon pinion.
now wish
hour wheel
in
to find the
which
number
of teeth of a missing
H represents the wheel.
H X 25 _ ^^ 10 X 10 ÂŤ = 12 4
H = 48 teeth of the hour wheel. Let us suppose that a complete minute wheel and pinion are missing in which
M
is
the wheel and
XM = 12 m 14
48
X
24
M = 12
7m
M
12X7 _ m"~~24
7 2
_3^ ~~ 1
m
is
the pinion.
WHEEL WORK The
31
shows that the minute wheel must have 3^^ times as many teeth as the minute pinion has leaves. Thus result
M_28_35_42_49 m~" 8"~10~12~~l4 Any
of the above solutions
may
be used as the following
equations will show.
48X28 14 X8
48X35
48x42
48x49
X
X
X
14
10
14
12
14
= 12
14
Problems 1.
What
2.
How many trains
3.
Name
4.
How many
is
meant by
train ?
Name
has the ordinary watch ?
the wheels of the average
main
them.
train.
turns does the escape wheel
make
center wheel in an 18,000-beats-per-hour train?
to one of the
How many
turns
in a 19,800-beats-per-hour-train? 5.
What
are the arguments in favor of the fast trains for very-
small wrist watches 6.
What
?
portion of the space between the barrel and the arbor
should the mainspring occupy ? 7.
What
is
the correct thickness of the mainspring
if
the barrel
has 80 teeth with an inside diameter of 13 millimeters and the center pinion has 10 leaves? S.
Name
9.
How many
10.
Name
the parts of the dial train.
turns does the hour wheel
make
in 12
hours
?
the various types of dial trains. Explain their difference.
Part I
CHAPTER TWO
Gearing Terminology Gearing constitutes a system of wheels and pinions whose circumferences are covered with teeth so that the
The
teeth of the wheel act
upon the leaves of a
function
a system of levers in which a longer
is
in reality as
lever presses
on a short one
until
pinion.
one lever ceases to press and
another lever comes into action.
Gearing
is
a rather technical subject and
study Figure
The terms given
5.
in
it Is
well
first
to
the illustration are
defined as follows:
Pitch circle: a a toothed wheel
circle concentric
and cutting
its
with the circumference of
teeth at such a distance
from
their points as to touch the corresponding circle of the pinion
working with
and having with that
it,
circle
a
common
velocity, as in a rolling contact.
Pitch diameter Full diameter:
:
the diameter of the pitch circle. the diameter
from point
to point of the
teeth.
Distance of centers: the distance measured on a straight line
from center to center between the wheel and pinion. 32
GEARING
33
a line drawn from center to center of
Line of centers:
any wheel and pinion. the pitch circle divided into as
Circular pitch:
many
spaces as there are teeth on the wheel or pinion.
divided into as
many
diameter of the pitch circle
the
Diametrical pitch:
spaces as there are teeth on wheel or
pinicn.
ADDENDUM DEDENDUM
Figure
Addendum:
5.
the portion of the tooth, either of wheel or
pinion, outside of the pitch circle.
Dedendum:
the portion of the tooth of either wheel or
pinion inside of the pitch
Driver
:
Driven:
circle.
the mobile that forces the other along. the mobile that
is
being forced along by the
driver.
Principles of Gearing
The addenda.
In Figure 6
A, representing the pitch portion of a circle
is
is
shown a portion of a
circle of a wheel.
another
circle,
gircle,
Rolling on this
B, the diameter of which
A PRACTICAL COURSE IN HOROLOGY
34
Figure
6.
Formation of the epicycloidal curve.
equals half the pitch diameter of the pinion.
If a pencil
point were fixed at the lowest point of the circumference of the smaller circle (the generating circle) and then rolled on
the larger circle without slipping, a curve would be traced
along the path of the line
The curve thus formed
C
in the direction of the arrow.
called the epicycloid
is
and determines
the shape of the addenda of the wheel teeth.
The dedenda. The dedenda by the same generating
The
smallef circle
of the pinion.
is
circle
of the pinion leaves
but not
rolled inside
is
formed as shown by the
A
Figure
7.
within a circle
A is
circle
line
and along the pitch
rolling
called a hypo-
cycloid and determines the shape
of
the
leaves.
pinion
dedenda of the pinion
Thus when a wheel and are made in conformance
with the above principles of de-
formed
same manner.
However, instead
of a curved line a radial line
in
in the
is
Figure
7.
circle
GEARING sign,
a smooth and constant force
Width
of tooth.
It
is
35
delivered to the pinion.
has been observed that the generating
forms one side of the tooth. The question now arises This is as to how to determine the width of the tooth. determined by dividing 360 (degrees in any circle) by the circle
number of
teeth in the wheel.
This gives us in degrees the
width of one tooth and one space, generally referred to as the circular pitch.
360
= 4.5 degrees circular
Thus
pitch.
80 teeth
The width pitch
;
of the tooth
the other half
is,
4.5 degrees
Therefore
is
equal to one half of the circular
of course, equal to the space.
= 2.25
2 of which 2.25 degrees
is
the width of the tooth and 2.25
degrees the width of the space.
Now, by
placing the generating circle, E, Figure
6,
with
the pencil point directly below and 2.25 degrees to the right
of curve C,
it
will be in position to trace out the other side
of the tooth by simply rolling the circle to the left as
by the dotted
C and The
line
The
D.
intersection of the
shown
two curves,
D, forms the point of the tooth. pitch diameter.
We now
wish to determine the pitch
diameter of a wheel and pinion, the center distance being
known.* The
first
procedure
is
to determine the diametrical
determined by means of a depthing tool, an instrument with adjustable male centers that can be adjusted to the holes in the plate and convenienth' measured with a micrometer or Boley gauge. *
The
center distance
is
—
:
:
:
A PRACTICAL COURSE IN HOROLOGY
36
pitch, the
formula for which reads as follows center distance
X
2 :
teeth of wheel
The
-j-
r-.
—=
.
,
.
,
diametrical pitch.
leaves of pinion
diametrical pitch
is
now
multiplied by the
number of
teeth in the wheel in order to determine the pitch diameter
manner the
of the wheel, and in like multiplied by the
number of
diametrical pitch is
leaves in the pinion to determine
the pitch diameter of the pinion.
For example, the center distance
is
8.5 millimeters
wheel has 80 teeth; the pinion has 10 leaves. the numerical values for the above formula,
80+10
;
the
Substituting
we have
= .1888 diametrical ^
pitch.
Continuing the problem we find that
= 15.104 mm. pitch diameter of the wheel. .1888 10 = 1.888 mm. pitch diameter of the pinion. 15.104+1.888 ^ ,^, „ = 8.496 mm., the distance between Proof: X X
.1888
80
^
,
,.
centers.
The
full
diameter.
quantity depending
The height
on the
of the addenda
ratio of the
is
a varying
wheel to the pinion,
but the production of theoretically correct gears or even
knowing when they
exist
is
not possible with the equipment
available to the practising horologist. to
add
The
usual practice
is
2.5 diametrical pitches to the pitch diameter of the
wheel and 1.25 to the pitch diameter of the pinion.* Experi* There
one exception to the above statement For the dial train where the pinions drive the wheels and the wheels drive the pinions, as in the case of setting the watch to time, the addenda is figured as 2 for both wheels and pinions. is
:
:
:
:
GEARING
37
ence has shown that the above figures are best for
all
practical
purposes.
We
found that the wheel has for
its
pitch diameter 15.104
millimeters and the pinion 1.888 millimeters.
The
diametrical
pitch multiplied by 2.5 gives us the height of the addenda
for the wheel
X
.1888
2.5 == .47
Adding this to the 15.104
Now,
pitch diameter of the wheel,
+ .47 = 15.57 mm. full diameter of the wheel. we have
figuring the pinion
= .236 1.888 + .236 = 2.12 mm. X
.1888
We
we have
1.25
full
may, however, figure the
work by adding teeth or leaves.
diameter of the pinion.
full
2.5 or 1.25 (addenda) to the
.1888
Circular pitch.
mm. 2.12 mm.
The
=
It will
the
difference
full
diameter of the wheel.
full
diameter of the pinion.
be noted that the definition for
somewhat
circular pitch reads rical pitch.
number of
For example
(80 4- 2.5) .1888 == 15.57
(10+1.25)
diameters with a lot less
is
like the definition for diamet:
circular pitch
is
the division
of the circumference of a circle (the pitch circle), whereas the diametrical pitch
is
(the pitch diameter). leaves
is
the division of the diameter of a circle
In both cases the number of teeth or
the divisor.
We must know the actual width of tooth and space in order to select a cutter to
make
a wheel. Herein
of calculating the circular pitch.
To
lies
the importance
attain this
use of the following formula: pitch diameter
X
3.1416
teeth or leaves
= one circular pitch
we make
:
:
A PRACTICAL COURSE IN HOROLOGY
38
Substituting the numerical values
X
15.1
3.1416
= .592 mm. circular pitch
80
The proportion of for the wheels
tooth or leaf to space
is
usually
one half of the circular pitch.
:
for the pinions, 10 leaves or less
:
one third of the circular
pitch,
for the pinions,
12 leaves or more
:
two
fifths
of the
circular pitch.
Now,
continuing with the above example to determine the
width of the tooth of the wheel and the leaf of the pinion,
we
find that
.592
= .296 mm., the width of the tooth, and
2 .592
= .197 mm., the width of the
leaf.
Problems 1,
What
2.
Define diametrical pitch.
2.
Calculate the diametrical pitch for the following:
the epicycloid? the hypocycloid?
is
—
center distance
7.5 millimeters,
—75 pinion — 10 leaves. wheel 4.
teeth,
Calculate the pitch
diameter for the above wheel and
pinion. Calculate the full diameters.
in
5.
Define circular pitch.
6.
Calculate the circular pitch, using the specifications given
Problem
J.
:
Tl
Part I
CHAPTER THREE
The Lever Escapement Time and experience have demonstrated of the lever escapement over timepieces.
become in
In
obsolete.
the
fact,
Since
all
several
other types for portable
other
types
introduction by
its
1750 the lever escapement has been the
experimentation and study. state of perfection
we
see
the superiority
have now
Thomas Mudge object of much
was developed into the today only after a number of
It finally it
unique and fantastic variations were tried and discarded.
Terminology The
several parts of the escapement are defined as follows
ESCAPE The escape wheel
is
WHEEL
that part of an escapement that delivers
impulse to the balance through the
Ratchet-tooth wheel:
the
medium
name given
of a pallet fork. to the English
type escape wheel, which has pointed teeth.
Club-tooth wheel:
that type of escape wheel
which has
a lifting face at the end of the teeth. Impulse face: the lifting
plane of a club-tooth wheel.
Locking face: the slanting face
of the teeth on which the pallets lock.
Toe: the intersection
of the locking face and the impulse face of a club tooth. 39
A PRACTICAL COURSE IN HOROLOGY
40
Heel: the intersection of the impulse face and the letting-off corner of a club tooth.
PALLET FORK The
fork
pallet
means of
pallet
that part of an escapement that,
is
jewels, receives impulse
by
from the escape
wheel and delivers impulse to the balance.
name given to the metal body to which is attached. The term includes the pallet jewels.
Pallets: lever
Lever:
the
a metal piece attached to the
impulse to the balance.
The fork
the
pallets that carries
occupies the extreme end
of the lever.
Fork
slot;
a notch cut into the fork for the reception of
the roller jewel.
Horns: fork •
the circular sides of the fork that lead to the
slot.
Receiving pallet
that pallet stone over which a tooth of
:
the escape wheel slides in order to enter between the pallet stones.
Discharging pallet
:
that pallet stone over
which a tooth
of the escape wheel slides in order to leave from between the pallets. Impulse face: the lifting plane of the pallet stone. Letting-off corner: the extreme end of the impulse face of a pallet stone
where the tooth of the escape wheel
Locking face: the face of a
pallet stone
lets
on which a tooth
ofiF.
locks.
ROLLER TABLE The jewel.
roller table
is
the circular disk that carries the roller
THE LEVER ESCAPEMENT Crescent:
41
a circular notch in the edge of the roller table
for the reception of the guard pin or fingeV.
a roller action comprising a single metal
Single roller: disk.
Double
roller
a roller action comprising two metal disks,
:
the larger disk carrying the roller jewel and a smaller disk in
which a crescent
is cut.
Roller jewel or jewel pin:
a flattened jewel that
is
inserted in the roller table.
BANKING PINS Banking pins are pins motion of the
that arrest or limit the angular
lever.
Equidistant, Circular and There are three types of lever
escapement:
the
S emit an gent al
pallet
Pallets
arrangements used in the
equidistant,
the circular
and the
semitangental.
Equidistant pallets.
In the equidistant the locking faces
of the pallets are an equal distance from the pallet center,
Figure
8.
Equidistant pallets.
A PRACTICAL COURSE IN HOROLOGY
42 as
shown
As
in Figure 8.
a result the lifting action on the
discharging pallet takes place too far from the point of tangency, necessitating the need for a greater lifting angle
on that stone.
Although the unlocking
favorable conditions, the lifting action in its distribution
its
performed under
is not,
being unequal
and unequal also as to the pressure of the
tooth on the pallets.
accuracy in
is
This escapement
calls for exceptional
construction.
c
f
Figure
Circular pallets.
9.
Circular pallets.
Circular pallets have the central portion
of the pallets' lifting faces an equal distance from the pallet center as
shown by the
lines
CA
half of the width of the pallets lines,
is
and
DA
in Figure 9.
One
placed on each side of these
which requires that the locking faces stand
at
an un-
equal distance from the pallet center, causing an unequal and increased unlocking resistance. is
more
lift
favorable.
Semitangental
mon
However, the action of
fault
in
pallets.
Setting on the locking
is
a com-
small wrist watches; hence a light lock
is
THE LEVER ESCAPEMENT
Figure essential to
10.
Semitangental
pallets.
With regard
good performance.
43
to this factor
the semitangental escapement, a development of recent years,
has found favor with
many manufacturers because
it
lessens
the resistance to unlocking, a natural fault with the circular,
and
at
the
equidistant. It will
same time minimizes the
be observed that the unlocking on the receiving pallet
EB
at the intersection of
slightly increased center distance results,
CA
is
The
of the
Figure 10 shows the semitangental escapement.
takes place on the tangent
A
lifting error
since the line
placed 31 degrees to the left of the center line
action of the discharging pallet
escapement with circular
pallets.
is
The
the unlocking and lifting actions are
CA.
BA.
similar to that of
an
designers claim that
more nearly equally
divided than any escapement that has yet been conceived.
Number Although nearly teeth
of Teeth in Escape all
Wheel
watches have an escape wheel of 15
we may make them
with
12, 14, 16, or practically
any
:
M
A PRACTICAL COURSE IN
HOROLOGY
number in this range. The first lever escapement as made by Thomas Mudge had an escape wheel of 20 teeth. The larger numbers result in a rather clumsy action and are Escapements using a wheel of
therefore not satisfactory.
12 or 14 teeth are used today in some wrist watches and have
For example, there
certain advantages.
between the
number of
pallet
arm and
is
more clearance
the escape wheel.
The
smaller
teeth permit the use of wider pallet jewels
and
a wider lifting plane for the teeth. Also the actual measure-
ment of 1^2 degrees of locking
is
greater because of the
increased distance between the locking comers of the pallets
and the
pallet center.
Wheel and The tions:
lever escapement has
is
two
distinct
and separate func-
(1) the action of the wheel and pallets and (2) that
These functions we
of the fork and roller. sider.
Pallet Action
The
first,
which has
divided into three actions.
to
shall
now
do with the wheel and
They
con-
pallets,
are
1 the locking
2 the draw 3 impulse or
The on a is
locking.
pallet
when
lift
The locking
Is
the overlapping of a tooth
the lever rests against the bank. This locking
necessary for the reason that
and another tooth
falls directly
opposite pallet, there
is
if
one tooth
lets of?
a pallet
on the impulse face of the
a recoil of the lever toward the
balance, causing a frictional contact between the guard pin
and
roller table.
stop the watch.
Contact in this manner would immediately
To
avoid this a certain amount of lock
Is
THE LEVER ESCAPEMENT However,
necessary.
should be as
it
as possible con-
with the proper safety in action.
sistent
The draw.
In portable timepieces the lock in
sufficient to insure safety in action.
an action whereby the is
little
45
effected
pallets are
It is
drawn
CA
slanting should be as
and
little
DA
into the wheel.
shown
as
not
necessary to create
by inclining the locking faces of the
right of the lines
itself is
This
pallets to the
in Figure 10.
This
as possible, yet enough to overcome
the friction of the tooth on the surface of the pallets, for it
can readily be seen that the combined action of lock and
draw makes a
resistance to the motion of the balance
and
has an important relationship to the position and isochronal rating of a watch. It
is
pallet
generally conceded that 12 degrees
is
However, because of the
satisfactory.
motion of the
draw on each
pallets the
draw
is
circular
changing continually, being
strongest on the receiving pallet at the point of unlocking,
whereas on the discharging
pallet
it
is
weakest
at the point
The nature of this action leads one to assume that a greater angle for draw should be given to the receiving pallet in fact, we find some authorities designing the escapement with 13 to 15 degrees draw on the receiving pallet. This would make the draw more nearly equal at the point
of unlocking.
;
of banking where
The
lift.
it is
most needed.
In well-designed escapements of the club-tooth
variety the actual
lift is
8^
degrees, being divided between
tooth and pallets in varying proportions.
Adding 1^^ degrees
for the lock, the total angular motion of the lever becomes
10 degrees.
Width
of pallet
and tooth.
It will
be observed that a
:
A PRACTICAL COURSE IN HOROLOGY
46
wide
a narrow tooth
pallet requires
;
likewise a
should be associated with a wide tooth kept to the minimum.
if
narrow
the drop*
pallet
to be
is
In this connection several pallet and
tooth combinations are listed below
CIRCULAR PALLETS TOOTH
PALLET
Width
Lift 1
6
2
5J4
degrees
7
degrees "
5
5"
654
6
"
^
4
5
"
•'
"
Width
Lift
3^
2J^ degrees "
354
"
4>^
"
3^ 4H
degrees "
Ay2
5^
"
"
EQUIDISTANT PALLETS 6
5
7
degrees "
7
degrees
5H 5^
6
Lift
Width
2y2 degrees
3 5^ degrees
Width
Lift
6
"
5M
"
"
"
3
"
3
Attention should be given to this fact pallets the lift
on the tooth should be
4^
"
than the Hft on the
Circular and equidistant pallets are not always
pallets.
However, there are exceptions,
interchangeable.
case of
"
in the equidistant
:
less
454
Number
1
and Number
5,
been interchanged by Grossman.
which are
Number
4
alike is
as in the
and have
suitable only
for circular pallets, especially so since the narrow pallets
perform the act of locking nearer as
shown
in
Figure
9.
to the lines
CA
and DA,
Numbers 5 and 6 would be
suitable
also for the semitangental escapement.
a term used to indicate the free motion of the escape wheel after one tooth lets off a pallet and another tooth locks on the opposite pallet. This factor is of more concern in practical benchwork and is treated fully in Part II, Chapter Six. *
Drop
is
THE LEVER ESCAPEMENT
47
The Fork and Roller Action The
relation
between
the fork and roller jewel as a mechanical action
may be
divided into two distinct and separate functions:
(1) the
Unlocking and impulse actions.
unlocking of the pallets and (2) the impulse to the balance.
One
action
is
the reverse of the other.
takes place as a result of
The unlocking
action
power derived from the balance
and spring, while the impulse to the balance receives
its
energy from the force delivered to the escape wheel by means In the unlocking action,
of the main spring and the train.
a short lever (roller- jewel radius) acts on a longer one (the lever fork).
A
must be associated
short roller-jewel radius
with a long lever which involves a large angle of contact as
shown by the angle
ABC
in
Figure
11.
On
the other hand,
a long roller- jewel radius must be associated with a short lever
which
the angle
results in
ABC
a small angle of contact as shown by
in Figure 12.
In other words, the shorter
the roller- jewel radius the larger
the angle of contact, and
is
the smaller the angle of contact the longer
is
the roller- jewel
radius.
A
4-to-l roller action.
In Figure 11 the relation of the
roller jewel to the fork slot is
4 to
1
;
that
is,
the lever
moves
10 degrees and the roller jewel remains in contact with the
The
fork slot for a space of 40 degrees.
action of unlocking
begins quite some distance from the line of centers because of the short roller-jewel radius.
jewel radius results in a
unlocking of the
A
much
However, a short
roller-
safer action and an easier
pallets.
3-to-l roller action.
In Figure 12 the relation of the
roller jewel to the fork slot is 3 to 1.
Although the unlocking
A PRACTICAL COURSE IN HOROLOGY
48
is
more
difficult,
energetic
when
it
action
roller jewel
the impulse to the balance
does occur.
with the fork
The 30-degree
slot is in
is
more
contact of the
accord with the theory
that the lever should be as highly detached as possible for finer results in timing.
Figure
11.
Fork and tion
The more radius
is
work we exact in
roller ac-
—single
delicate
roller.
Figure
12.
Fork and tion
roller ac-
—double
roller.
safety action of a long roller-jewel
not a problem in high-grade watches, for in such naturally expect a mechanical action that
its
function.
It follows, therefore, that
is
more
a long roller-
jewel radius which involves a small angle of contact
is
one
THE LEVER ESCAPEMENT
49
of the important factors to be considered in fine escapement
Of
design.
watches
A
course, in the cheaper
it is
wide
work and
in small wrist
not always practical.
The wide
roller jewel.
roller jewel results in
particularly satisfactory action of unlocking
a
by taking place
near the line of centers. However, the impulse to the balance is
not so favorable.
A
wide
roller jewel is inseparable
from
a long roller- jewel radius, for such a principle of design results in a very delicate action.
the safety action
A
narrow
much
A
wide
roller jewel
makes
less delicate.
roller jewel.
A wide
roller jewel, if associated
with a short roller- jewel radius, causes an unfavorable impulse to the balance too far from the line of centers,
and the
"uphill" circular path of the roller jewel along the side of
the fork slot during the impulse to the balance results in Also, on account of the greater angle
considerable friction. at
which the
roller jewel stands to the slot
when
the impulse
takes place, the drop of the fork against the jewel will to
more than
on the
its
shake in the
line of centers.
adapted for a short
slot, if
amount
measured when standing
Thus a narrow
roller jewel is better
and should always
roller- jewel radius,
be associated with a single-roller escapement. Single-roller escapement. In the single-roller escapement,
Figure
11,
it is
required that the roller table be as small as
possible to preserve the safety action.
Furthermore, friction
between the guard pin and the circumference of the table
was
would be considerably increased on a
larger than necessary.
motion of the lever to
less
It is difficult to
roller
table roller that
reduce the angular
than 10 degrees, and any relation
of fork to roller jewel less than a
3^
to
1 is
not practical.
V
A PRACTICAL COURSE IN HOROLOGY
so
Double-roller escapement.
'
We
have learned,' that
we
order to favor the impulse to the balance
ii^
require a long
and for the safety action a short radius.
roller-jewel radius,
the reason for the passing of the single-roller escape-
This
is
ment
in favor of the double-roller type, Figure 12, for in the
latter
type
The
we have two
rollers,
size of the safety roller is of
For the sake of soundness less
one for each action.
no great importance.
in action its radius
should not be
than one half the radius of the roller jewel. The smaller
the safety roller the sooner will the crescent approach the
guard
finger;
and,
likewise,
the
longer
the
roller-jewel
radius the later will the roller jewel enter the fork
slot.
It
follows, therefore, that the greater the difference between
the respective radii of the roller jewel and the safety roller the longer
must be the horns of the
roller jewel also plays
fork.
The width
of the
a part in the length of the horns, for
with any increase in the width of the jewel, the horns
may
be made proportionately shorter.
The
The
crescent.
circular notch in the roller
is
called
the crescent and should be wide and deep enough so that will be impossible for the it.
If
guard finger
to touch
made too wide, longer horns on
it
any part of
the fork would be
required to preserve the safety action.
The width is
of the crescent in the double-roller escapement
greater than in the single-roller type, for the reason that
the guard finger, due to
space to cover for in another
way
:
it
its
its
increased length, has a larger
safety action, or, stating the function
could be said that the velocity of the guard
finger has increased, whereas the velocity of the safety roller
has decreased.
THE LEVER ESCAPEMENT
51
Problems
as
1.
How
2.
Compare
3.
What
4.
Define draw.
differ
do the equidistant pallets
is
from the
the above with the semi-tangental escapement.
meant by locking?
How
does draw differ on the receiving pallet
compared with the draw on the discharging 5.
circular pallets?
How many
pallet ?
degrees are generally intended
for
the lifting
action ?
and
6.
Explain the difference between a 4 to
7.
Which
8.
Describe the single and double escapements.
of the above actions
is
1
preferred?
3 to 1 roller action.
Why? State the advan-
tages and disadvantages of each type. 9.
roller
10.
What
is
the
name
of the small roller that
escapement ?
What
is
the purpose of the crescent?
makes up the double-
Part I
CHAPTER FOUR
The
Controlling
The balance and of a watch and ism.
balance spring are the most vital parts
be properly called the controlling mechan-
Years ago the principal
rate time
difficulty in
was the temperature
unknown
balance was
much
may
Mechanism
maintaining accu-
error, since the
prior to 1769.
compensating
Often the error was as
as four or five minutes in twenty-four hours.
variation
is
due to three conditions
:
(1)
the expansion
The and
contraction of the metal in the balance, (2) changes in the length of the balance spring, and (3) variation of the elastic
force of the spring.
the spring
is
The
variation of the elastic force of
the most important factor; in fact, Ferdinand
Berthoud has estimated that 82 per cent of the error
is
due
to the variation of the elastic force.
Experimental demonstration.
A
simple experiment to
prove the correctness of the above statement
Figure
52
13.
may
be tried
;
THE CONTROLLING MECHANISM if
The
desired.
S3
materials needed are a sheet of brass about
4 or 5 inches long and 2 inches wide, a piece of brass wire,
and an old mainspring.
two
Drill
holes,
A
and B, Figure
13,
about yi inch apart and insert two brass pins and rivet Straighten the outer portion of the mainspring
securely.
and place the end between the
A
placed under pin
spring,
after
noticeably, as
The
Now, with
blowpipe heat the brass the
extreme end being
and over pin B, while the coiled portion
passes beyond the index C.
serve as a weight.
pins, the
coil
spring on the index.
will
the aid of an alcohol lamp and
plate.
It
becoming heated
may
beyond the index
will
be observed that
slightly,
has
deflected
be seen by noting the position of the
Upon
cooling
it
will return to its orig-
inal position.
Temperature Error of the Balance and Balance Spring The compensating balance. The compensating balance, or bimetallic balance, as
was designed
to
it
is
sometimes
called.
Figure 14,
overcome the errors resulting from the use
of the solid balance.
This balance
is
constructed by brazing
together brass and steel for the rim of the balance. brass
is
on the outside and constitutes about three
The
fifths
of
the total thickness.
Heat causes the metals
in the balance
assembly to expand
the arms become longer and, as the brass expands
more than
the steel, the loose ends of the rim curve inward toward the center.
Cold causes the loose ends to move outward away
from the clearly
center, while the
shown
in
Figure
15.
arms become It will
shorter.
This
is
be further observed that
the loose ends remain reasonably circular during temperature
A PRACTICAL COURSE IN HOROLOGY
54
Figure
14.
Compensating balance,
changes, but the radii of the curves change, their centers
O
for the normal temperature and
AA
for the high and low tempera-
being at the balance center shifting along the tures.
arms
However, the points BB, about 60 degrees from the
arms, remain at a fixed distance from the balance center, and it is
at these points that alterations for the
purpose of timing
should be made.
Middle-temperature error.
It is
evident from the above
analysis that
we can
manner
compensate for the expansion and contraction
as to
adjust the balance screws in such a
of the balance alone and maintain a constant This, however,
mean
diameter.
would not take care of the lengthening and
shortening of the balance spring nor for the changes in the
;
THE CONTROLLING MECHANISM
Figure
elastic force.
To compensate
on the spring,
it
is
55
15.
for the effects of temperature
necessary to add extra weight to the loose
ends of the rim. This results in a temperature error, between the extremes of heat and cold,
known
as the middle-tempera-
ture error due to the fact that the balance does not comforce and
pensate equally for changes in the elastic
changes in the length of the spring. sufficient
This
is
compensation (weights not moving
toward the center of the balance)
shown by
in
in the higher
for in-
near enough
temperatures
and too great a compensation (weights moving too far away
from the center)
in the lower temperatures.
The
result
is
a higher rate in the normal temperature, usually from two to six seconds in twenty-four hours, depending on the grade
of the watch.
A PRACTICAL COURSE IN HOROLOGY
56
Figure
This factor indicates the
is
clearly
uniform
shown
16.
in Figure 16.
To
by some means of compensating the
would be a constant mean
2ec
AB
exactly offset this rate error,
the opposite effect indicated by the line results
line
due to a rising tempera-
loss in the rate
ture on the balance spring only.
The
we must produce
CD. The
theoretical
rate along the line
EF.
THE CONTROLLING MECHANISM However, since the actual compensating alone
lies
to that
along the dotted line
shown
There
is
GH,
S7
effect of the balance
the actual rate
is
similar
in Figure 17.
no way of rectifying
this condition
except to use
a nickle-steel alloy called Invar, the perfection of which has
been realized only in recent years.
expands and contracts only a very temperature, and in using
it
the middle-temperature error Still
more
This remarkable metal little
instead of the ordinary steel is
considerably reduced.
recently another type of alloy
nickle-chromium, and tungsten and
Figure
18.
for changes in
known
Solid balance.
made
of iron,
as Elinvar has
A PRACTICAL COURSE IN HOROLOGY
58
been developed for the use of balance springs. Elinvar maintains
a constant
elasticity
and
is,
therefore, used in connec-
tion with a solid, single-metal balance as
The metal has and only
shown
in Figure 18.
the further advantages of being nonrusting
slightly subject to
no middle-temperature
magnetism.
Also there can be
error.
The Balance Spring There are two forms of balance springs in general use. These are the flat spring, Figure 19, and the Breguet, Figure 20.
The former has
the stud fixed to the
same plane as the
body of the spring, with the result that the vibrations take place in an eccentric manner. The latter, referred to as Breguet, has a portion of the outer coil raised above and
over the body of the spring.
The
original Breguet spring
was created by Abraham Louis Breguet (1747-1823), famous French horologist, but the spring by him bore no resemblance
Figure
\
19.
Flat balance spring.
THE CONTROLLING MECHANISM
59
-YA
Figure
20.
Overcoil balance spring.
to the theoretical terminals as applied to
The
modern watches.
we now find them are based on the foundadown by M. Phillips, French mining engineer, and
terminals as
tion laid
have placed the art of adjusting on a Theoretical terminals. corrected terminals
scientific basis.
The value of
lies in their
the theoretically
capacity to correct position
and isochronal errors by eliminating the eccentric wanderings of the center of gravity that are everpresent in the
The
flat
spring.
outer and inner terminals designed by L. Lossier perform
this function
very satisfactorily. These are shown in Figures
20 and 21. In the outer terminal, Figure 20, note that the overcoil
composed of portions of two
circles.
The outer
coil
is
tends
A PRACTICAL COURSE IN
60
HOROLOGY A
inward at
and forms an arc
of 180 degrees to B, which
is
planted at a point equal to .67 of the radius R.
The
overcoil
continues for another 83 degrees, the radius of
which
is
CO. To this must be added the amount necessary to reach through the stud. Figure 21 shows the Lossier inner terminal.
The elements
of the curve are the same as Figure
Theoretical inner terminal,
21.
clearly
shown
the
in the illustration.
applied to practically
all
corrected inner terminal
outer
terminal
Although the overcoil
is
not, its use being confined only
The reason no doubt
fact that the Lossier inner terminal is difficult to
harder to adjust and, unless the curve is
no
is
watches today, the theoretically
to the very finest watches.
it
and are
is
lies in
the
make and
100 per cent perfect,
better than a true terminal of the ordinary type.
Careful poising of the
collet is also necessary.
Problems 1.
Describe the compensating balance.
2.
What What
3.
is
type of balance springs are used with
balance wheels 4.
5. 6.
How What Draw
the middle-temperature error?
?
does the Breguet spring differ from the
flat
spring?
are the advantages of the theoretical terminals? a sketch showing the proportions of the theoretical
curves, both outside and inside.
\
solid, single-metal
PART
II
PRACTICAL REPAIRING
Part II
CHAPTER ONE Train Problems General
observations
in
gearing.
Attention
should
always be paid to the action of the outgoing tooth, noting that
up
its
its
point
is
not used and that the incoming tooth takes
load without drop.
The incoming
tooth should begin
pressing on the pinion leaf as near as possible to the line of centers, allowing for the fact that this
depending on the number of leaves
is
a varying quantity
in the pinion.
The
best
possible actions for pinions of ten, eight,
and six leaves are
shown
Figure
in Figures
1, 2,
and
3.
Note that
in
1
the action
begins on the line of centers, in
Figure 2 slightly before the
line
of centers, and in Figure 3 quite
some distance from the
line of
centers.
Gearing
may
be found defec-
tive with regard to several factors.
Below are
listed the
common. Pinion too large Pinion too small
Depthing too deep Figure
1.
Depthing too shallow
Ten-leaf pinion.
62
most
TRAIN PROBLEMS
Figure
Let us
2.
Eight-leaf pinion.
now examine
Pinion too large.
Figure
3.
63
Six-leaf pinion.
the errors in the order listed above.
Referring to Figure 4
it
will be ob-
served that the incoming tooth butts into the end of the pinion
Figure
4.
Pinion too large.
Figure
5.
Pinion too small.
A PRACTICAL COURSE IN HOROLOGY
64 leaf,
thereby stopping the watch.
If the error
is
slight the
action can be improved by enlarging the wheel, in which case
the outgoing tooth will propel
a
tooth.
Pinion too small. in a
leaf farther, resulting in
clearance between the incoming leaf and the in-
sufficient
coming
its
A
waste of power and
pinion too small, Figure
much
5,
results
noise, since the outgoing tooth
propels the leaf even to the point of slipping off before the
incoming tooth has started to press on a too small, the incoming tooth will leaf.
Wear
is
fall
leaf.
Hence,
Figure
6.
is
much
with a click on the
considerable and an error of this kind should
never be allowed to pass without correction. The larger pinion
if
fitting
of a
the only satisfactory solution.
Depthing too deep.
Depthing too deep.
Figure
7.
Depthing too shallow.
In a depthing too deep, Figure
the outgoing tooth continues
its
6,
action too long, most likely
with the point affected by excessive wear and a loss of power.
TRAIN PROBLEMS
A
Depthing too shallow. always unsatisfactory. Note propel
a
shallow depth, Figure
7,
is
that the outgoing tooth cannot
enough and the incoming tooth presses on
leaf far
its
65
In a very shallow depth a
leaf before the line of centers.
Enlarging the wheel some-
butting action usually results.
times puts the depth in a passable condition.
Worn
pinions.
If a
watch stops
with the slightest movement
and see
if
they are worn.
it is
Modern
and
in friction.
Wear
when
well designed gives
about 18 degrees
as a result quite
is
time will cause trouble.
in
starts
wrist watches frequently
service, but has the disadvantage of
engaging
and
well to look at the pinions
use a six-leaf escape pinion, which
good
in the train
pronounced
Often the fourth wheel can
be raised or lowered so that the wheel drives the pinion on the previously unused portion.
Repairing a Train The enlarging of
Stretching a train wheel. is
train wheels
a job that comes occasionally to the horologist,
for
it
happens that some watches are not right when they leave the factory.
It is,
of course, better to
are times, particularly
if
the watch
that enlarging the old wheel that
if
serve
the wheel
its
is
a
fit
is
new
not an expensive one,
permissible.
was imperfect
wheel, but there
The
to begin with
purpose and the watch runs
better,
fact
remains
and wx make
we
it
feel justified
in the act.
The
staking tool
preferred that
be used to stretch the wheel.
we work on
that the markings
when
may
the watch
is
made by
It is
the lower side of the wheel, so the
assembled.
flat
punch
We
first select
will not
be visible
a hole in the
A PRACTICAL COURSE IN HOROLOGY
66
die to loosely
fit
either the staff of the pinion or the entire
may
pinion as the case
The
require.
die is so adjusted that
the rim of the wheel comes under the punch.
frequently
It
happens that the part of the rim we wish to work on comes over, or partly over, another hole in the die.
happens
we may
This will hold a
select
a larger hole and plug
To
we
stretch a wheel
use a
this
with
pith.
while stretching the rim
staff in position
over a smooth and solid part of the
it
When
die.
flat- face
punch of such width
as to completely cover the rim including the teeth.
punch gently a succession of blows and the wheel slowly.
at the
Tap
the
same time turn
This stretches the rim satisfactorily and
with scarcely any visible punch marks, except where the arms are crossed.
To
keep the wheel as nearly round as possible,
sary to stretch the arms, as
we
it is
neces-
should not rely on the cutter
of the rounding-up tool to bring the wheel circular. Stretching of the arms
is
done separately
of the rim and teeth
—and
—
^that is,
after the enlarging
great care should be exercised
so as not to overdo the stretching.
The rounding-up we are ready to use
tool.
Having
finished the stretching
the rounding-up tool.
of the brass beds the diameter of which
First, select
is sufficient
one
to sup-
port the wheel and at the same time be perfectly free of the cutter.
Next,
tween the
select a cutter that exactly fits the space be-
teeth.
Occasionally,
we
find wheels the teeth of
which are too wide. In such cases a wider cutter is required in order to reduce the teeth to a width that will satisfactorily gear into the pinion. it
in the tool,
we
Having
center
it
selected the cutter
in line
and placed
with the guide, a knifelike
TRAIN PROBLEMS piece provided for the purpose of teeth will be cut perfectly upright.
up
is
now
making
67
certain that the
Tha wheel
to be rounded-
placed between centers and so adjusted that the
wheel turns freely and the rim barely touches the brass bed. Carefully advance the cutter so as to engage
See also that the guide on the cutter
wheel.
it
with the
is
properly
centered within the space preceding the one that the cutter
Cut the wheel but proceed
occupies.
carefully.
It is well to
try the wheel frequently in the watch so as to not overdo the correction.
Problems i.
How many
leaves are required of a pinion so that the action
begins on the line of centers 2.
Name
3.
If a train
4.
Why
5.
If
reason ?
?
four defects that are sometimes found in gearing.
is
is
noisy what
may
be the reason?
a shallow depth always unsatisfactory?
a watch stops frequently in the train,
what may be the
Part II
CHAPTER TWO Jeweling The
use of jewels as bearings for watches
question,
is,
without
one of the most important achievements to the Nicholas Facio, an
attainment of precision timekeeping.
residing in London, successfully applied jewels to
Italian
watches about the year 1704. The system used by Facio was not the same as employed in making the jeweled bearing of today. Instead of a hole piercing a jewel, a V-shaped depression
was ground
worked the
into the jewel.
The
into the depressed jewel in
present-day alarm
much
finally resulted in the
the
same way as
The Swiss were quick
clock.
realize the advantages of jeweling
which
was pointed and
pivot
in to
and began experiments
making of jewels as we
find
them today.
Bezel-Type Jeweling Jeweling of the bezel type
is
when
a rather difficult task
attempted by the usual hand methods. Yet the lathe attach-
ment intended for such work siderable
number of jewels
describe only the
is
practical only
are to be
hand method
set.
We
—a method
Few
tools are needed.
con-
shall, therefore,
which, after the
necessary experience, will satisfy the needs for purposes.
when a
all practical
These are a supply of
drills,
the usual gravers, a jewel graver, Figure 8, and a burnisher,
Figure
9.
68
JEWELING
69
Bottom
Side
Figure
Figure
The procedure
is
9.
Jewel graver.
8,
Jewel burnisher.
of four-millimeter brass wire.
and turn a small
Secure in the lathe a piece
as follows.
center.
Face
off the
end of the wire
Select a drill slightly smaller than
the jewel to be used and bore a hole about five millimeters deep. it
up.
With the jewel graver Next turn a seat to fit
enlarge the hole slightly to true the jewel.
The depth should be
sufficient so that the jewel will lie slightly
below the surface
of the wire. Next, cut a groove close to the opening for the jewel with a long, pointed graver. inserted but should
keep
it
from
first
falling out.
The
jewel
is
be moistened with a
Now
now little
rest the burnisher
to be oil
to
on the
T-rest; thrust the point of the burnisher in the groove,
A PRACTICAL COURSE IN HOROLOGY
70
Figure
Figure
10.
11.
Bezel type jewels.
forcing the brass against the jewel, thereby holding the jewel
A
in place.
may
jewel thus set
and the brass Figure 10
desired.
if
shows the work as described above. The dotted
show
the figure
the
the watch plate.
off.
perfectly secure
be faced off level to the jewel
clearly
fit
is
manner
End
which the
in
shake
is
setting
lines in
turned to
is
tried before the wire
This being satisfactory the wire
is
cut
is
cut
turned to
off,
the proper thickness, and stripped out with a sapphire jewel stripper or a highly polished graver.
by
sliding the setting
file
previously prepared with a
Three are is
face
is
polished
on an agate polishing stone or burnish
Number- 1
styles of bezel-type jewels are
shown
The
in Figure 11.
The method
buff.
used
in
watches and
for setting
all styles
the same.
Friction Jeweling Friction jeweling of watches
is
a simple and quick method
of inserting a jewel in a plate, bridge, or setting by means of friction.
Swiss manufacturers started using this system
1920, and since then
in
more and more manufacturers, both
Swiss and American, have adopted this method.
JEWELING In
fitting
a friction jewel, the
mine the depth the jewel This
shake.
made
is
procedure
is
to deter-
to be set to give the proper
end
accomplished by using a machine especially
for the purpose, of
the market.
is
first
71
which there are many
First, rest the
varieties
on
pusher on the broken jewel and
adjust the metric screw near the top of the machine so that the
new jewel may be
broken one had been.
forced in to the same depth as the
Second, push out the broken jewel
and ream out the hole with the smallest reamer that
away enough metal
will cut
to give to the plate a clean, straight hole.
Third, select the proper jewel, the outside diameter of which is
1/100 of a millimeter larger than the hole in the
Remove
plate.
the burr left by the reamer with the wheel counter-
sinks and push the jewel in place.
Replacing a friction jewel. watch that had a
To
friction jewel in
it
replace a jewel in a before,
it is
necessary
only to measure the size of the hole in the plate. This
may
be done by inserting the reamers or using a special gauge that
is
Having determined the the jewel required and push it in to the proper
available for the purpose.
hole size, select depth.
Figure
12.
Friction Jewels.
n
A PRACTICAL COURSE IN
HOROLOGY
Fitting jewel in removable setting. jewel in a setting that
may
If
we wish
to
fit
a
be removed from a plate, as in
the case of a balance or cap jewel,
we need
special tools to
hold the setting securely while reaming out the hole. There are various types of tools on the market
all
of which are
used in connection with the friction- jeweling machine. Several types of friction jewels are shown in Figure 12.
Problems 1. 2. 3. 4.
set?
What are the tools Name the styles of
How How
needed
in fitting bezel-type
jewels?
bezel-type jewels used in watches.
do friction-type jewels
differ
from bezel-type jewels?
do you determine the depth a friction-type jewel
is
to be
Part II
CHAPTER THREE
Making a Balance Many
Staff
horologists consider the making of a balance
a difficult task.
We
find
staff
workmen doing almost anything
a watch to avoid the necessity of making a bridges are bent up or down.
to
Balance
staff.
Unsightly graver marks are
found on plates and bridges. The balance arms are sometimes bent out of line in an attempt to permit the balance to clear the various parts, and pivots are often ground too short.
However, the making of a
man would go
staff is
not
difficult if
the repair-
about learning the art the same as with any
other performance requiring
skill.
No
one ever learned to
play a musical instrument in a few lessons or ever became
an expert engraver
in
a few months.
Preliminary Notes on Staff Making Gravers for turning
shown general
staffs.
Three gravers of the
in Figure 13 are needed for staff work. use,
suitable
also
for
B
staff prior to cutting
it
for
has a rounded point
for turning the cone portion of the cone pivot. is
is
square shoulders and the
cylindrical portion of cone pivots.
point flattened and
A
styles
C
has the
used for turning the lower end of the off.
73
A PRACTICAL COURSE IN HOROLOGY
74
ABC
Figure
13.
Gravers for turning balance
Sharpening the gravers.
seem it
Sharpening the gravers does not
to be given the attention
We
should.
staff.
by the average horologist that
have seen v^orkmen trying to cut a square
shoulder pivot with a graver having a point like a wire
Naturally their
work was
unsuccessful, yet these
nail.
workmen
did not reflect on the fact that possibly the graver was at fault.
The graver must have a sharp
point.
Even
the best
gravers cannot retain a keen edge very long while cutting
tempered
steel.
Therefore keep a sharpening stone handy and
make frequent use carborundum wheel
of
it.
Some workmen use an emory
to grind gravers.
done, as the point of the graver this point is the
is
most important
This should never be
frequently softened and
part.
Instead
we
use two
stones, a soft
Arkansas stone and a hard Arkansas
The
is
soft stone
for rapid cutting
or
and the hard stone
stone. is
for
the final finishing. After grinding the face, sHde the sides on
the stone so as to produce a
Making tice
flat
pivots for practice.
and smooth cutting surface.
The beginner should
prac-
making square shoulder and cone pivots before attempt-
MAKING A BALANCE STAFF ing the making of a
staff.
It will
75
be found that the larger
pieces of pivot wire are excellent for the purpose, as the
wire
is
hardened and tempered, ready for use. The length of
the cylindrical portion of a cone pivot
The
is
length of a square shoulder pivot
twice the diameter. is
three times the
diameter.
Measuring for the staff. Now, returning to our problem of making a staff, the first act is to take the necessary measurements, preferably from the watch, for the reason that the old staff
may
not be correct.
The well-known Boley gauge
serves the purpose very well,
since
reads both ways,
it
between the calipers and from the end of the the balance bridge lies
the
cap jewels.
flat
Make
securely pushed in place.
Figure
14,
with the lower certain
that
For the
measure from the
full
foot.
plate.
the
See that
Now remove
hole
jewels are
length of the staff A,
side of the lower hole jewel to
Figure
14.
A PRACTICAL COURSE IN HOROLOGY
76
The
the side of the upper hole jewel.
the roller table
B
is
height of the seat for
found by measuring the distance from th^
side of the lower hole jewel to the top of the lever, adding
enough for clearance and the thickness of the In like manner the distance for the balance seat
from the
roller table.
C is measured
side of the lower hole jewel to the top of the pallet
bridge, adding for the necessary clearance.
the upper end of the staft
D
is
The
length of
found by subtracting the
C from
length of the lower end to balance seat
the full
length A.
Preparing the is
Preparing the
steel.
next in order. Select a piece of
will
be a
finished.
little
steel,
steel
wire for the staff
the diameter of which
larger than the largest part of the staff
Heat over a gas flame
to a cherry red
place so as to see better the degree of heat, for
too bright, one
ruin
and plunge
This should be done in a rather dark
quickly into water.
is
when
if
the light
apt to overheat the steel and thereby
is
it.
The wire is now too hard to turn and we must therefore draw the temper. The wire must be made white in order to blue
it.
This
is
done
in the lathe
emory paper against the
The tempering
is
by holding a piece of
fine
wire.
done by drawing the wire through the
flame of an alcohol lamp; or, better
still,
lay the wire
on a
curved sheet of copper, keeping the wire rolling while being held above the lamp.
A
full
blue color
is
satisfactory for
staffs.
Turning the
staff.
Tighten the wire securely
in the lathe,
having extended the wire from the chuck sufHciently to include the full length of the staff and about
two millimeters
MAKING A BALANCE STAFF
Figure
With
additional.
15.
77
Pivot polisher.
hand graver turn the upper end
the
—
first
turning the balance seat to length from the end and almost
Next
to size, say .05 of a millimeter of the finished diameter.
turn the collet axis, followed by turning the remaining end nearly to the size of the hole in the roller table.
Turning a conical the pivot almost to
pivot.
size.
Turn
the cylindrical portion of
Next, using the graver with the
point slightly rounded, turn the cone, bringing
it
down
meet the cylindrical portion of the
is
followed
by cutting the slope between the
pivot.
collet axis
This
to
and the cone of
The turning of the upper end of the staff is now completed and we are ready for the pivot polisher and the
the pivot.
preparation of the grinding mediums.
The
pivot polisher.
very neat
little
The
pivot polisher, Figure 15,
instrument for grinding and polishing.
superiority of the instrument over any
questionable
;
it
hand method
is
is
a
The un-
does the work in a factory-like manner and
polishes the pivot
the pivot polisher
most is
beautifully.
It is to
not more generally used.
be regretted that
A PRACTICAL COURSE IN HOROLOGY
78
However, the successful use of the pivot polisher depends on the proper preparation of the laps and we
shall digress
moment to consider the method by which they are made how to keep them in good condition, and their varifor a
—
We
ous uses.
need laps of cast
and box-
iron, bell metal,
wood, and the material may be purchased from hardware stores
and material houses.
Cast-iron
and
bell
rial
may
and
bell-metal laps.
Laps made of
metal are used principally for grinding.
cast iron
The mate-
be purchased in rods of various diameters. For most
needs of the horologists, rods of about will suffice.
Having
^
selected the materail,
about ^2 inch long and bore a hole in
it
inch in diameter
saw
off a piece
of such size that a
reamer of the required taper may be used to enlarge the
The
hole
is
hole.
reamed out with a reamer of the same taper as
the taper chuck
shown
in
Figure
16.
The blank
is
placed in
Laps of various shapes are needed. Those most used are shown in
the taper chuck for turning with the slide rest.
Figure
17.
Figure
Figure
17.
16.
Taper chuck.
Laps for pivot
polisher.
:
MAKING A BALANCE STAFF Having turned the
and
laps, the face
79
must be
side
filed to
enable the lap to hold the grinding or polishing medium. Filing,
admitted, has a tendency to destroy
it is
this is
necessary in order to do good work.
shown
that
is
it
run practically
Number 4
possible to
File the lap
true.
or 5
The
so.
a lap
Experience has
many
by laying
truth, yet
times and face
it
still
down on a
Holding the lap between the thumb and
file.
along the cutting teeth of the
fingers, slide the lap
an inch or
file
its
lap should then be turned partly
and another stroke made. This crosses the
lines,
about
file
around
providing
a suitable surface for the embedding of the abrasive medium.
Next, prepare the side of the the lap on the lap.
file
This
lap.
is
done by drawing
in a direction parallel to the hole in the
Continue in this manner until the entire circumference
is filed.
Boxwood
polish on steel.
Boxwood laps are used for putting a high We may use the slide rest in turning the
boxwood
same manner as we did
cast-iron
of the
laps.
in the
and bell-metal
wood run
parallel
laps.
in preparing the
important that the grain
It is
with the hole in the lap so that the
end of the grain touches the work. The lap face only with a
Number
Now
ready, the preparation of the grinding
We proceed as
that the laps are
medium
is
next in
follows
Apply a small quantity of
oilstone
powder
to the first
partment of the three-compartment polishing block. little
watch
thin paste
oil
is
on the
file.
Preparing the grinding material. order.
is filed
and mix with a small knife or spatula
com-
Add
a
until a
produced. Place the pivot polisher on the lathe
and adjust the
lap spindle so that
from the bed
as the lathe spindle.
it
stands at the same height
Adjust the index
at the
A PRACTICAL COURSE IN HOROLOGY
80
base of the polisher to }i degree, so as to give the staff a slight taper
With
toward the end when the grinding takes
place.
the belting so fitted that the grinding surface of the lap
and the surface of the
staff rotate in opposite directions to
each other, feed the lap up to the work by means of the hard-
rubber knob at the rear. Apply thinly but evenly the oilstone paste to the lap and grind the balance seat.
grinding until the balance just
undercutting
is
fits
Continue the
the seat.
Be
sure the
deep enough so that the corner of the lap
does not touch the
staff.
be riveted true and
flat
If this
when
grind the collet axis to size
;
is
the case the balance can
the staff
is
Next,
finished.
after which, grind that portion
of the staff between the cone of the pivot and the collet seat.
Grinding and polishing a cone pivot.
Clean the work of
the grinding material with a piece of pith previously dipped in benzole
and hold
it
a dry piece of pith.
against the
staff.
For the cone
Finish cleaning with
pivot, the polisher is set
with the spindle at right angles to the pivot with the index set at
degree.
It is
further adjusted so that the center of the lap stands above the pivot as
shown
This
in Figure 18.
reduces the straight portion of the pivot perfectly cylindrical
and forms the cone time.
The shape
at the
same
of the cone
can be varied by raising or lowering the
spindle
of
the
polisher.
Instead of the cast-iron lap Figure
18.
Method of polishing
conical pivot.
we now
use a bell-metal lap
and a grinding medium of cro-
MAKING A BALANCE STAFF Reduce the
cus. fits
pivot, frequently trying the jewel until
Now
rather closely. place a
its
boxwood
diamantine and
oil
lap
remove the bell-metal lap and
and polish the
fit
it
in
pivot, using a paste of
previously prepared on the top section of
Continue the polishing
the polishing block. fits
81
until the pivot
the jewel freely.
The slope between the collet axis and the cone of the pivot may now be smoothed further by holding a jasper slip in the hand. It is then polished with a boxwood slip and diamantine.
Turning hub and roughing out lower end that the
upper end of the
staff is finished
the hand graver a long slope
lower end of the
With
stafif.
from the balance
seat to the
the pivot polisher set at the its
length, using
Smooth further with jasper with boxwood lap, diamantine, and oil.
powder and
and polish
Now
we next turn with
necessary angle, grind the slope for most of oilstone
of staff.
slip
oil.
Next, cut out roughly the lower part with a graver slightly flattened at the point.
the finished staff
Cut is,
is
off the staff
of course, a
and the
little
longer than
roller axis a little larger.
and measure the overall length. The
staff
Place the collet axis in a
split
little
chuck and stone
down
to be
Leave the hub a
too long.
off the
lower end until the
to the correct length.
Remove
staff is
worked
the staff and remeasure
the overall length between the calipers of the Boley gauge as
many
times as
is
required, taking only a
at a time so that the staff will not be
positively the
correct length.
little oflf
made too
short.
most exact method of bringing a
Any
the end
This
is
staff to the
other method, such as measuring back
from a predetermined amount of extra length and cutting off after the work is cemented, is likely to result in errors.
A PRACTICAL COURSE IN
82
Figure
HOROLOGY
Cement chuck.
19,
The cement chuck. The staff having been brought to the correct length we are now ready for the cement chuck. A screw brass tightly screwed turned in
it,
a chuck must have a center
deep enough to take the
cluding the hub. in place
in
up
staff
Figure 19 shows the center with the
and properly secured
lamp under the cement
that the brass will melt the
same time running the still
soft,
staff
cement and
insert the staff with the
Place a small
Heat
brass.
lathe slowly.
Again keeping the lathe
in-
in the cement.
Setting the staff in the cement chuck. alcohol
and
to
fill
sufficiently so
the center, at the
While the cement
thumb and
is
finger.
first
in motion, reheat the brass until
the cement adheres to the staff.
Holding the
staff in place
with a hollowed-out piece of pegwood resting on the
T
continue running the lathe until the cement
cooled.
Now,
true
up
is slightly
the staff while the cement
resting the pointed end of the
still
is
pegwood on the
bringing the pointed end against the roller axis.
must be placed staff in place
at
an angle so that we
may
T
while allowing the cement to cool.
soft
by
rest
and
T
rest
The
first
rest,
hold the
The
truing
MAKING A BALANCE STAFF follows immediately by holding the
and at a right angle to the
83
pegwood
front of
in
staff.
Turning the lower end of the staff. Turn the lower end of the staff, measuring from the end up to the roller seat, and bring the hub to the correct length. Reduce the roller axis to 0.1 of a millimeter of the correct diameter.
Set the pivot
polisher in position with the index adjusted to
^
degree
taper and grind the roller axis until the roller table slides
on and wedges
tight at a distance about
up
The
to the hub.
two
thirds the
way
pivot is next turned and polished as per
instructions already given.
The boiling
staff is
now removed from
the cement chuck. Fill the
pan or test tube with alcohol and
Finishing the ends of the pivots.
have not yet been finished but in the in
watch and
what manner
test for
it is
boil off cement.
The ends
well
first
of the pivots
to try the staff
end shake, so we may know better
to proceed.
Since the measurement for the
was made without allowance for end shake, it usually follows that a slight touching up of the ends of the pivots is
length
needed.
and
To
flatten
accomplish
this, place
the staff in a split chuck
each end slightly, using a hard Arkansas
slip.
Polish further with a jasper slip and finally finish with a
hardened
steel
burnisher and round the corners slightly.
COMMON
ERRORS IN STAFF MAKING
Beginners are very apt to overlook certain important details in the turning of is
a
staff.
One
of the most
common
the absence of a square shoulder for the roller seat, so
that the roller table will not
lie
flat
to the full diameter
of the hub. Undercutting for this purpose
is
not objection-
A PRACTICAL COURSE IN HOROLOGY
84
many watch
able, for
In
manner
like
factory staffs are
made
the balance wheel should
manner.
in this
the staff, that
fit
is,
the full diameter of the hub.
flat to
The
collet axis, the balance axis,
show a
and the
should
roller axis
definite taper so that the parts in question will
properly.
This
the instrument
fit
easily attained with the pivot polisher, for
is
may
be set to the desired taper.
In using
must be trained to recognize a
the hand graver, the eye suitable taper.
The
straight portion of the pivots should be cylindrical
and not tapering as we sometimes should be shaped
alike.
it.
the balance seat
also important.
Success will be realized
not as
difficult as
and likewise more
difficult
Satisfactory undercutting at the top of
to attain without
attention to detail,
and the cones
Again these conditions are made
possible with the pivot polisher
is
find them,
and
it
if
will
the beginner will pay strict
be found that
staff
some workmen would have you
making
is
believe.
Problems 1.
What
2.
How
3.
Explain in detail the hardening and tempering of the
staff 4.
gravers are needed in turning a staff?
do you measure for a
staff? steel for
making,
Name
the steps in turning the upper end of a staff in their
proper order. 5.
How do you
6.
Must
7.
Name
go about bringing the
staff to the
proper length ?
the staff run absolutely true in the cement chuck?
the points of particular importance in staff making.
Part II
CHAPTER FOUR
Pivoting Success drills
and
in pivoting
depends largely on the quality of the
in keeping the drills sharp.
pinions without tempering, yet there are times
ing must be resorted
to,
and
the
It is better to drill
when temper-
in such cases a small copper
wire shaped as shown in Figure 20
may
be used. The leaves
of the pinion are held in a pin vise or parallel pliers to prevent the heat
from spreading to that part while the copper
The end
heated over an alcohol lamp.
tempered to a blue
of the pinion
is is
color.
The pinion may be centered
in the split
chuck
true; otherwise, the cement chuck must be used.
if it
runs
Face
off
the pivot to the square shoulder and turn a small center. in a pin vise
and
a hole, which
Place the pivot
drill
should be a
deeper than the length of the average pivot.
Should the drill is
little
drill
it
immediately.
A
dull
apt to burnish the bottom of the hole, presenting a
serious problem. drill,
cease to cut, sharpen
drill
Should
which usually
this
happen, flatten the end of the
results in the drill cutting again.
The
hole having been drilled to a satisfactory depth, secure a piece of pivot wire in a pin vise, start
and hang
and
file
in the hole in the pinion.
exercised in filing the wire to
show 85
as
sufficiently to just
Caution should be
little
taper as possible.
86
A PRACTICAL COURSE IN HOROLOGY
Roll the wire as the filing takes place so as to leave the wire
round. Finish with the Arkansas
Next, force the wire
slip.
in the hole, cut off the wire with the cutting pliers,
the plug with a small
securely in the hole.
and tap
hammer, thereby forcing the plug
The
pivot
is
turned nearly to size with
the hand graver and finished to the proper size as already
III
I
I
I
I
I
I-T1 I
Figure
20.
Copper wire
in position for
I
I
I
II
umi
tempering pinion.
PIVOTING It is advisable to
explained.
undercut the square shoulder
slightly before polishing in order to
shown
in
87
keep the corner sharp as
Figure 21.
Figure
21.
Problems 1.
What
are the important points to
remember
a pinion
in drilling
for repi voting ? 2.
If
a
drill
ceases to cut what
may
be done so that the
drill will
cut again ? 3.
loose
What would be
the
when turning with
most Hkely reason for a pivot working
the graver ?
:
:
Part II
CHAPTER FIVE Fitting Balance Springs In fitting balance springs the
first
procedure
is
to deter-
mine the number of vibrations of the balance per minute. This
by
may
dividing the
first
the
be found in any watch
number of
number
with a second hand
of teeth in the fourth wheel
leaves in the escape pinion
number
ing the quotient by twice the wheel,
fitted
we have
ascertained the
;
then,
by
by multiply-
of teeth in the escape
number
of vibrations of the
balance per minute.
For example, the fourth wheel has 80 teeth; the escape pinion has 8 leaves
;
the escape wheel has
1
5 teeth.
80X30 = 300 vibrations of the balance per minute 8
Other examples are as follows
72X30 = 270 vibrations per minute 8
64X30 = 240 vibrations per minute 8 In watches where the seconds
we have
to
go back
fourth wheel
does not register
to the center wheel, as
the following examples
54
X
50
X 48 X
6X6X6
30
= 18,000 vibrations per hour 88
shown
in
FITTING BALANCE SPRINGS 64
X
X
66
60
X
30
8X8X6
89
= 19,800 vibrations per hour
Fitting a Flat Spring In
a
fitting
the proper
flat
spring to a watch,
This
size.
is
to the balance jewel as
radius
located
is
proximate strength,
necessary to
know
determined by centering the spring
shown
on the
inner regulator pin.
it is
first
we which may Next,
Figure 22.
in coil
The
correct
that stands inside the
desire to determine the ap-
be found by suspending the
balance and spring an inch or two above the bench. distance between the point where the spring
tweezers and the rim of the balance
is
is
If the
held by the
J^ inch, the spring
approximately of the strength
is
desired.
It
balance
is
large
or
small
if ;
the
the
remains practically the
distance
same.
does not matter
Of
course, this does not
necessarily decide that a particular spring is to be used, but
eliminate
all
it
does
unnecessary attempts
at vibrating a spring that is positively unsuited for a balance.
After trying several springs, finally selecting
to the above
cedure
is
one that conforms
test,
the next pro-
to vibrate the spring.
This can be done by counting the vibrations or by using an instru-
ment commonly known brator. r
Since nearly .
of recent years are
all
as a vi-
watches
J with a made '.1
Figure 22. Method for determining correct size of flat
^^^^^^
^^^-^^^
— A PRACTICAL COURSE IN HOROLOGY
90
300-beats-per-minute train,
it is
convenient to use the vibrator,
about which more will be written in the next paragraph. For the other trains
it
using a watch of
known
count the vibrations,
will be necessary to
The counting
accuracy.
is
done with
every vibration that takes place in a clockwise direction
;
that
The usual practice is to suspend the balance and spring by means of tweezers supported in the lathe bed. The lower pivot of the balance staff is,
the return vibration
is
not counted.
rests
on the watch
there
would be 150 counts for a 300-beat
Thus, counting for one minute
crystal.
135 counts
train,
for a 270-beat train, etc.
The
vibrator.
houses or
may
Vibrators
be
properly timed.
that
is,
in
make
his
own
old balance
may
material
and spring
be consulted
the
if
instrument.
of using the vibrator
is
that of comparison
watching the balance spring to be vibrated and the
and noting whether or not both vibrate
vibrator balance unison.
made from an
Material catalogs
horologist desires to
The method
may be purchased from
We
may
slide the
tweezers as
much
in
as a half a coil
toward the center of the spring or out a quarter of a
coil
toward the outside without altering the radius too much for a satisfactory fitting of the spring.
Having found a spring one quarter of a spring
is
coil
that vibrates properly, break
beyond the vibrating
point.
it
off
Next the
pinned in at the stud and the balance bridge with
balance and spring attached
is
placed in the watch for the
final timing.
Fitting the Breguet Spring
The of the
fitting
of the Breguet spring to a watch involves
work of
fitting
a
flat
all
spring, plus the forming of the
:
FITTING BALANCE SPRINGS
Figure
23.
The diameter need not be so exacting; however,
overcoil. it
91
should not be larger than one half of the diameter of the
balance, including half of the screws.
We
assume that the watch
shall
in
need of a new spring
ideally suited to the Lossier terminal
The procedure and break
is
as follows:
The
BC
and
AB
gives us the length of
We
BC.
2
CO X
3.14
360
X S3
this
we must
resort
desire to find the length of the
(Figure 23).
Number 1
BC =
flat
length of the active portion of the
to a bit of calculation.
portion
Figure 23.
two millimeters beyond the
must be determined and for
overcoil
in
Vibrate the spring in the
off the spring about
vibrating point.
shown
is
The
following formula
^
:
A PRACTICAL COURSE IN HOROLOGY
92
The
CO
radius
multiplied by 2 gives us the diameter of
that part of the overcoil concentric to O.
2
CO
turn
Hence the diameter
multiplied by 3.14 gives us the circumference, which in
divided by 360 to determine the length of
is
Multiplying the length of
now
degree.
degree by 83 degrees gives us
1
5C.
the length of
We
I
desire to
know
added to BC, gives us the
the length of
AB, which, when
total length of the curve.
Number 2:
AB =
(AO
+ OB) 3.14 2
Since
AO + OB
the circumference
equals the diameter and since one half of required,
is
it is
only necessary to multiply
AO + OB by 3.14 to give the circumference and divide by 2. Now,
taking a practical example,
diameter of the spring
is
.67
to the elements of the curve,
= 2.68 mm.
Substituting this value for
may
CO
Thus
of the radius.
CO = 4 X
us suppose that the
8 millimeters. The radius would be
4 millimeters. According is .67
let
CO
in equation
Number
1
we
determine the angular distance for BC.
BC =
X
5.36
3.14
X
83
= 3.88 mm.
360 Substituting again
length of
^= AB For the
for equation
Number 2 we
learn the
AB. (2.68 -^
4)3.14 + -^— = ^^^^ 10.48 mm. 2
full
millimeters.
length
we add
3.88 and 10.48, giving us 14.36
FITTING BALANCE SPRINGS
We
now grasp
93
the spring at the point intended for the
regulator pins and slide the spring along a scale in order to determine the actual length of the curve, allowing for sufficient extra length for the spring to is
make a
permissible to
slight
mark
reach the stud.
It
at this point to indicate
the starting point of the curve.
We
Raising the overcoil. overcoil.
This
are
now
ready to raise the
accomplished with rather heavy tweezers.
is
Grasp the spring with the tweezers about 25 degrees from
where the inward bend
that point tightly
and press
into a piece of
shown
takes on the shape
in
Hold
starts.
softwood
until the outer coil
Figure 24.
over and, measuring 22 degrees from the again until the outer
Figure 25.
Bring
takes the form
tweezers of
Figure 26.
coil lies level
Turn
the spring
first
bend, bend
wnth the body of the spring,
in the raised portion so that the overcoil
shown
many
the spring
in
To form
Figure 23.
shapes are desirable.
Alterations
should be
the overcoil,
These are shown
made
gradually,
in
being
careful not to bend the spring too much, for in so doing, the
Figure
Figure
25.
24.
First
First bend in forming overcoil.
and second bends
in
forming overcoil.
A PRACTICAL COURSE IN HOROLOGY
94
Figure
spring
is
liable to
26.
Balance spring tweezers.
be considerably weakened and possibly
broken.
The
Lossier curve
is
not adaptable to most small watches
for the reason that the curve central portion of the total
is
brought in nearer to the
mass than these watches
However, the above analysis may be used as a
permit.
will
basis
for calculating other forms, since the length of the curve
The forms more
does not vary very much.
adaptable to
present-day small watches are shown in Figures 27 and 28.
In Figure 27 note that the radius of the overcoil along the path of the regulator pins the spring. degrees.
The
Again
is
length of the curve in Figure
the regulator pins
is
is
180 degrees plus 20
28 the portion of the overcoil
at
placed in a position nearly in line with
the full radius of the spring.
takes the
three fourths of the radius of
form shown
In
this type, the
in the illustration
curve usually
and the bend for
the overcoil starts at a point opposite the regulator pins.
Converting a Flat Spring into a Breguet In order to obtain a closer position and isochronal rate in a watch originally fitted w4th a desirable to
make
flat
spring,
it
is
the spring over into a Breguet.
sometimes In
many
FITTING BALANCE SPRINGS
Figure 27.
Figure
28.
95
A PRACTICAL COURSE IN HOROLOGY
96
watches where there
is
room enough under
bridge this can be done without
a case of
suitable for
of
two
circles
Figure 29.
this
much
kind
the balance
The curve
difficulty.
composed of quadrants
is
connected by a straight line as shown in
The
radii of the circles
A
and
B
about one half of the radius of the spring.
are equal to
Owing
5
spiral nature of the spring the radius of the circle little
the outer coil of the the
The
longer than that of circle A.
same
coil after it
flat
spring and the solid line
was formed
into a Breguet.
shows the same spring with the removed.
A
realized.
The
dotted line
clearer picture of
only change to be
circles
its
Figure
29.
a
CC
shows
DD
shows
Figure 30 lines
form
thus
to the
shorten the regulator pins and raise the stud.
c \
is
and dotted
relative
made
to the
is
watch
is
The curve
to is
:
FITTING BALANCE SPRINGS
Figure theoretically correct to be equal to
and
if
any type of
97
30.
properly executed
it
will be
found
overcoil.
Eccentric Motion of the Spring After a spring has been vibration coil.
may
The
fitted
to
a watch an eccentric
be observed due to a faulty form of the over-
rules for correcting the eccentric
motion are as
follows 1.
If the eccentric motion takes place opposite the regula-
tor pins (as in
a
flat
spring), bring in part of the overcoil
toward the center of the spring. 2.
If the eccentric motion takes place on the
the regulator pins,
main body of the
move
same
side as
part of the overcoil hack into the
spring.
Truing Balance Springs The attainment
of successful balance-spring truing comes
only with continued practice and patience.
It is
one of those
A PRACTICAL COURSE IN HOROLOGY
98
are
accomplishments that
For
printed page.
difficult
this reason
we
through the
teach
to shall
make
only a few
general statements as to the manipulative operations.
In truing the round spring beyond the that the spring to be out as
is
never necessary to manipulate the
it is
first
quarter of the inner
shows a spring divided into quarters.
point.
The
assuming
true except for that portion which
a result of pinning in at the
referred to as
coil,
first
spring
and the procedure
collet.
The
quarter, half, third quarter,
may
is
likely
Figure 31
sections
are
and pinning
be wide at or near any of these points
in truing consists of
the spring in the desired directon.
The
pushing or twisting
dotted lines in Figure
32 show the manipulating required to bring the spring true in the round.
2
Figure
31.
FITTING BALANCE SPRINGS
Figure
Dotted
32.
lines indicate
manner
in
99
which the balance spring
is
twisted to true in the round.
In truing the
flat
the spring
is
pushed down or raised up
at those points that are high or low.
Problems 1.
Give the formula for determining the number of beats per
minute of a watch. 2.
How
do you determine the correct
size of a flat spring for
a
given watch ? 3.
How
4.
What
do you determine the correct is
6.
How do you go about How do you correct
is
the
How same
if
the
6.5 millimeters ?
forming the overcoil ? an eccentric motion of the spring that
takes place opposite the regulator pins 7.
Breguet spring?
the correct length of a Lossier outer curve
diameter of the balance spring 5.
size of a
?
do you correct an eccentric motion that takes place on
side as the pins ?
Part II
CHAPTER
SIX
Escapement Adjusting In this study of the
we
lever escapement
concerned with practical benchwork
that
;
are particularly
is,
good order the escapement of a given watch.
the placing in It is
important,
however, that we have some understanding of the theoretical principles involved
much
and
shall
w^e
indulge, therefore, in as
theory and escapement design as
is
necessary to aid
in the execution of practical repair problems.
The importance of understanding be
overestimated.
the escapement cannot
Large pocket watches often
function
quite satisfactorily with faulty escapements but with small
wrist watches ladies'
it is
very different.
The escapement
watches must be practically perfect.
in small
Since the larger
per cent of the watches that are brought in for repair today are wrist watches there
work.
is
need for greater
skill in
escapement
Inadequate knowledge results only in an endless
amount of trouble with watches perhaps only occasionally.
that stop persistently, though
Erratic rates, too, can be traced
to defective escapements,
Wheel and The
best
escapement
way is
Pallet Action
to obtain a practical understanding of the
to proceed step
by
100
step,
studying the separate
ESCAPEMENT ADJUSTING functions, after
be analyzed.
101
which the escapement action as a whole
Our
will
attention will first be directed to the prob-
lem of banking the escapement to the drop.
Banking means that
The term "banked
to the drop.
to the drop"
the banking pins are turned in such a position
that a tooth of the escape wheel will slide past the letting-off
corner of a
pallet,
thereby permitting the lever to reach the
opposite banking pin.
In order to effect a banked-to-the-drop condition, first
necessary to turn in both banking pins.
face of one pallet will
now show
contact with the impulse
owing
that the banking pins have been turned
the tooth
in,
to pass the letting-off corner of the pallet.
to the fact is
unable
Let us assume that
the impulse faces of the receiving pallet and a tooth
Turn the banking away from the line
rests,
pin, against
of centers slowly until a tooth
instant another tooth will lock pallet.
At
this
on the locking face of the
dis-
Next, move the lever to the opposite banking
pin, resulting in a contact being
shown between the impulse
Turn
the banking
away from
the line of
faces of the discharging pallet and a tooth. pin, against
show
which the lever now
passes the letting-off corner of the receiving pallet.
charging
is
The impulse
face of a tooth of the escape wheel, but
contact.
it
which the lever
rests,
centers until the tooth drops as already explained, and the
job of banking to the drop
is
completed.
DROP LOCK The
extent of the lock on the pallets after an escapement
has been banked to the drop
is
called
drop
lock.
This lock
takes place the instant a tooth drops on the locking face
of a pallet.
A PRACTICAL COURSE IN HOROLOGY
102
In Swiss watches and some American wrist watches
it is
not practical to bank the escapement to the drop because of the fact that the banking pins are not supplied with eccentric
In this case the usual practice
screws.
lever until the escape tooth drops
cease
moving the
A
and
to slowly
same
at the
slight additional
the
instant
motion of the lever
should be required before the lever will reach is,
of course, beyond that of drop lock.
is
called slide
and
move
and take note of the extent of the
lever
lock on the pallets.
is
The
will be considered
its
bank, which
additional motion
further in the later
portion of this chapter.
Drop
Correct drop lock.
lock
pending on the position of the arm, but
it
pallet
stones in the pallet
should be as light as possible consistent with
A
proper safety in action. the
a varying quantity, de-
is
drop lock of 1^^ or 2 degrees
is
amount usually adopted for pocket watches, whereas 2 or
3 degrees
is
allowed for wrist watches.
Altering the drop locks.
If the
drop locks are too light
or unsafe, a deeper lock can be had by moving out one or
both
pallets.
Likewise
lock can be had by
be observed that
on both
pallets
if
the drop locks are too deep a lighter
moving
when one
and any
in
one or both
pallet is
moved
pallets.
the lock
is
It will
changed
alteration of the pallets should always
be followed by rebanking to the drop.
Out on
of angle.
The
lever should
either side of the line of centers.
move an If the
is
equal distance
If the lever does not
said to be "out of angle."
drop locks are deep, out of angle can be corrected by
moving motion
equal distance the lever
move an
in the pallet is
shorter
on the side where the
from the
line of centers.
lever's
If the
angular
drop locks
— ESCAPEMENT ADJUSTING are light, out of angle can be corrected by
on the side where the
pallet
from the
If the
line of centers.
out of angle
(if slight)
lever's angular
103
moving out the motion
can be corrected by carefully bending staff.
This can be
done by holding the lever with a small pair of it
longer
drop locks are satisfactory,
the lever as close as possible to the pallet
bending
is
with the thumb and
first finger.
pliers
and
And remember
rebank the escapement to the drop after each alteration.
THE DRAW The
force that keeps the lever against
"draw."
It exists
its
bank
called
because of the inclination or slant of the
locking face and the shape of the tooth.
pallet's
is
It will
be
observed in Figure 36 that the receiving pallet inclines in the
toward the
direction
center, thus
degrees
is
and the discharging
pallet
away from the pallet draw. A draw of 12
the same direction but
in
inclines
pallet center
forming the angle for
considered sufficient by most horologists.
Examining the draw. Take a watch oiler or similar small tool and lift the lever away from its bank, but not far enough to cause the
and
escapement to unlock.
in so doing the lever will, if the
against the its
its
escapement
is correct,
bank.
bank.
The purpose of draw
is
to avoid unnecessary friction be-
tween the guard pin and the receives a jolt the lever
the guard pin action of
Draw to its
release the lever,
Try this again with the lever opposite banking. The lever should at once return
return immediately to
to
Now
comes
is
roller table.
When
thrown away from
its
the watch
bank and
in contact with the roller table, but the
draw causes the
lever to return at once to
its
bank.
should be sufficient to effect the return of the lever
bank for
all
ordinary conditions. If the draw
is
exces-
A PRACTICAL COURSE IN HOROLOGY
104
sive, there will
be an unnecessary recoil of the escape wheel,
causing a condition whereby too balance and spring
is
much
of the force of the
used in unlocking the escapement. The
waste of power and a shorter arc of motion of
result is a
the balance.
Altering the draw.
As
a rule want of draw
In most cases the jewel
sufficient angle of a pallet stone.
be tilted in the pallet arm. If the jewel
may
jewel
the jewel
be substituted or the
more
due to
is
slot
fits tightly,
in-
may
a thinner
may be widened
to give
angle.
THE DROP Drop
the time a pallet
defined as the free motion of the escape wheel at
is
when one
tooth passes the letting-off corner of
and another tooth comes
face of the opposite pallet.
in contact
Drop may be
with the locking
also defined as the
distance a tooth of the escape wheel travels without doing
any work.
Examining the drop.
With
a tooth locked on the re-
ceiving pallet observe the space that separates the letting-off
corner of the discharging pallet from the heel of the tooth.
Now move
the lever to the opposite banking pin, thereby
causing a tooth to lock on the discharging
Next ob-
pallet.
serve the space that separates the letting-off corner of the
from the heel of the
receiving pallet
Of find
course, the drop should be equal, but
it
so.
A
These errors
close inside, tip one or both pallets If close outside, tip
pallet staff.
not always is
and a small drop on the discharging
called "close inside."
stafif.
we do
small drop on the receiving pallet
"close outside," is
tooth.
call
called pallet
for correction.
away from
If
the pallet
one or both pallets toward the
ESCAPEMENT ADJUSTING moving one
Usually,
question
may
105
arise as to
which
move. This would
pallet to
depend largely on the condition of the draw, the drop
and the angular motion of the lever from the for
we
shall
any reason
soon learn that whenever a
all
The
pallet is all that is necessary.
line
locks,
of centers,
pallet is shifted for
of the above conditions are altered.
SHAKE Shake
is
defined as that space separating the letting-ofif
corner of the pallet from the heel of a tooth opposite pallet is
is
when
occurs at the time
the tooth
will be
is
for shake
locked at the lowest
When moving
locking corner of the pallet. its
the
locked at the lowest locking corner. Shake
similar to drop except that the examination
from
when
the lever
away
bank but not enough to unlock the escapement,
it
observed that a slight recoil of the escape wheel has
taken place. This action lessens the space between the lettingoff corner of the pallet
that shake
is
always
less
and the heel of the
tooth,
showing
than drop. If an escapement has no
shake the watch will stop.
THE LIFT Modern escapements have a total lift amount of lift separately on tooth and varying proportions in a club-tooth
requires
escapement
considerable
noticed that the
both
in different
pallets.
On
lift
is
of 83^ degrees.
pallet is designed in
makes of watches. The
lift
a very complicated action and
study to understand
it.
It
will
be
does not function exactly the same on
the receiving pallet the wheel
also does the pallet
The
and the
pallet's locking
greater velocity than the letting-off comer.
ing pallet the condition
is
moves up
as
corner moves with
On
the discharg-
reversed and the wheel moves
A PRACTICAL COURSE IN HOROLOGY
106
Figure
Figure
down
33.
34.
Lift
on receiving pallet
Lift on discharging pallet.
while the pallet moves up. Also, the letting-off
of the discharging pallet
moves with greater
comer
velocity than
the locking corner.
A
good action between the wheel and
pallets is
shown
in
Figures 33 and 34. Note that as the tooth leaves the locking faces of the pallets, the toe of the tooth
shows contact only
with the pallet's impulse faces. Contact in this manner continues
completely across the pallets until finally the two
impulse faces meet nearly parallel, and after that the heel
ESCAPEMENT ADJUSTING
Figure
Curved
35.
pallet stones
107
by A. Lange
&
Son.
of the tooth passes the letting-off corner of the pallets.
comes
heel of the tooth pallet
on the discharging
into action quicker
move
also there is a tendency for the tooth to
;
The faster
along that portion of the lifting plane near the letting-off
The
corner. that
is,
To
opposite takes place on the receiving pallet;
the action
is
faster at the start of the
obviate this difficulty, A.
lift.
Lange and Sons some years
ago made watches with escapements so designed that the receiving pallet had a convex lifting face, the discharging pallet
a concave lifting face, and the lifting faces on the teeth
were also curved (Figure 35). This system, served,
would cause the
tion at a
Loss lift
lift.
There
on the discharging
This
is
shown
in
from each
is
a definite amount of loss of
pallet of the club-tooth escapement.
Figure 36.
other.
be ob-
velocity.
5C
escape wheel describes the circle deviate
will
lifting action of the tooth to func-
more nearly constant in the
it
a straight line but the
is
DD
;
hence these lines must
In order that 5^^ degrees of lifting
take place, a lifting angle of
6%
degrees
discharging pallet. However, this loss of
is
required of the
lift is
a problem to
be reckoned with principally in the equidistant the circular pallets the loss of
lift is
very
little
pallets.
In
for the reason
108
A PRACTICAL COURSE IN HOROLOGY
p<
c a CO
â&#x20AC;¢3
ESCAPEMENT ADJUSTING
109
CO
u CO
;
A PRACTICAL COURSE IN HOROLOGY
no
mid-way between the locking
that the tangents are planted
and of
(Figure 37). The loss
letting-oif corners of the pallets
lift
in the semitangental
escapement
also small, usually
is
amounting to about one-half degree (Figure 40).
The Fork and Roller Action In this study of the lever escapement
we have up
till
now
concerned ourselves with such factors as banking to the drop
drop lock, draw, drop, shake, and the it is
We
lifting action.
These,
observed, constitute the escape wheel and pallet action.
now
are
which
is
ready to investigate the fork and roller action
quite a study in itself.
There
is,
however, a definite
relationship between the
two actions and the
cannot
studied
be
successfully
Hence
account of the former. in its entirety
was outlined
escapement
in satisfactory
The
is
this to a
lift
the wheel and pallet action
first
1^
and
it is
assumed that our
adjustment up to this point.
on the tooth and
drop lock of
mentioned
without taking particular
We
have stated that the
pallets is
S}^ degrees. Adding
lever's angular motion.
combined
last
degrees, the total angular motion
of the lever becomes 10 degrees.
The
of 10 degrees should be
is
all
that
lever's angular
motion
necessary for the roller
jewel to pass in and out of the fork satisfactorily without catching.
Now,
placing the balance in the watch,
ready to try the
tests
guard safety
and the corner safety
eyeglass in
test
making the
for the safety locks.
tests,
we proceed
test.
we
are
These are the
Using a strong
as follows.
SAFETY LOCK TESTS Guard safety
test.
Rotate the balance so that the roller
jewel stands outside of the fork and with the
first
finger
ESCAPEMENT ADJUSTING
Figure
3S.
Guard safety
hold the balance in this position. similar small tool,
lift
the lever
111
test
Now, with a watch oiler or away from its bank, thereby
causing the guard finger to come in contact with the edge of the safety roller as shown in Figure 38.
With
the lever
held in this position examine the remaining lock on the pallet.
This remaining lock
is
called a safety lock
and
it
should
A PRACTICAL COURSE IN HOROLOGY
112
represent one half of drop lock or }i
The
degree of lock.
should next
test
be tried on the opposite pallet and a similar lock should be found.
Corner safety
test.
Starting with
the roller jewel in the fork
rotate
slot,
the balance slowly until such time that
one tooth passes the
letting-off corner
of a pallet and another tooth comes in contact with the locking face of the
opposite
A
pallet.
motion applied
additional
slight
to the balance will bring
the roller jewel in a position opposite
With
to the slot corner.
held in this position,
from
Figure 39. Corner safety test. roller jewel as
its
lift
the balance
the lever
away
bank, thereby causing the
slot
corner to come in contact with the
shown
in
examine the remaining or safety opposite pallet and
if
With the lever held thus, lock. Try this test on the
Figure 39.
the safety lock
pallets the lever's angular
is
the
motion from the
same on both
line of centers is
practically equal.
The
shown by the comer test should be the same as the safety lock shown by the guard test that is, the safety locks from both sources should show }i degree of safety lock
;
—
Note Although this always work out in practice.
lock.
corner test test
—
that
freedom
is less
is, if
correct in theory
If the safety lock
on
it
does not
shown by the
than the safety lock shown by the guard
the corner freedom
—no harm
pallets is safe
is
results,
all
is
greater than the guard
provided that the locking of both
of the teeth of the escape wheel.
How-
ESCAPEMENT ADJUSTING ever, if the corner
the roller jewel
is
fork, causing the
freedom
is less
113
than the guard freedom,
apt to catch on the tips of the horns of the
watch
to stop.
The curve test. To test an escapement for the error stated above, we use what is called the curve test. To apply this test
is
it
necessary to rotate the balance so that the roller
jewel stands completely past the horns of the fork. Next, the lever finger to
the lever will
away from its bank, thereby causing come in contact with the safety roller is
lift
the guard
and, while
held thus, turn the balance so that the roller jewel
move toward
the fork
slot.
horns of the fork and enters the factory as far as this test
is
If the roller jewel passes the slot,
concerned.
catches on the tips of the horns, a tions could be present.
the escapement
is satis-
If the roller jewel
number of
The most common
faulty condi-
are: guard finger
too short, roller jewel advanced too far, or lever too long.
The drop
locks being correct,
it
is
now
apparent that the
guard, corner, and curve tests aid in determining the correct length of the lever.
work
It
is
to lengthen the lever
common
practice in escapement
by stretching
it
or to shorten
by grinding the horns as the case may require.
mind
that the condition of the drop locks
is
So bear
first
it
in
taken ac-
count of and the fork and roller action afterward.
Slide
Up
to this point in our discussion, the escapement has
been banked to the drop.
The
subject of slide
is
next in
order.
The opening
of the banking pins beyond that of drop
lock
called slide.
Slide should be large
is
freedom for escaping; usually }^ degree cient.
Any amount more
enough to permit
is
considered
suffi-
than this only increases the angular
:
A PRACTICAL COURSE IN HOROLOGY
114
motion of the lever and
its
connection with the balance,
resulting in an increased unlocking resistance, a shorter arc
of motion of the balance, and poor timekeeping. pins should be placed as far as possible
The banking
away from
the pallet
center so as to lessen the strain on the lever pivots should
the escapement overbank. Slide
is
the last adjustment, the finishing touches, so to
speak, in escapement adjusting.
The As let
sort of
Theoretically Correct Escapement
summary
of our discussion of the escapement,
us consider the specifications of a correctly designed
escapement.
When
banked
as follows
Drop
lock
to the drop, the specifications should read
ESCAPEMENT ADJUSTING
115
1 a
s «>
c bo
it
4>
A PRACTICAL COURSE IN HOROLOGY
116
purpose the semitangental escapement shown
for this
Figure 40, as
comprises the best and
it
latest
in
design in
escapement construction.
The
materials needed for drawing are
drawing instruments,
pencil,
drawing paper, and India
large
ink.
and a French curve would be
a drawing board,
:
and small protractors,
AT
two
square,
triangles,
desirable although not absolutely-
necessary.
Study the drawing thoroughly before
what points the various angles also, to
make
starting.
originate.
It is
Note
at
important,
the drawing on a large scale so as to minimize
the errors arising from imperfections in our drawing instru-
ments.
who have no knowledge
Students
of mechanical
drawing would do well to read several chapters
in
any good
textbook on mechanical drawing.
Recommended texts: Roberts, William E., Beginning Mechanical Drawing.
Manual Arts
The
Press, Peoria, Illinois, 1943.
Bennett, Charles A., Beginning Problems in Mechanical
Drawing. The Manual Arts Press, Peoria,
Illinois,
1934.
Practical Application of Escapement Tests
Knowledge of
the several escapement tests will be of
value unless they reveal the necessary corrections to be in defective escapements.
therefore, to
show
The purpose
made
of this section
is,
the application of the several tests as a
guide to escapement alterations. in the following
little
All of the examples listed
pages are based on actual problems experi-
enced and corrected by the writer in the course of practical
work
at the bench.
ESCAPEMENT ADJUSTING In
all
cases
is
it
first
117
assumed that the escapement was
banked to the drop.
Adjustment
1.
— correct Guard freedom — excessive Corner freedom —
Drop
locks
correct
In this escapement the guard freedom was greater than the
When
corner freedom.
the curve test
was
jewel would catch on the horns of the fork.
tried the roller
The
correction
consisted of flattening the end of the guard finger.
For
this
purpose a punch should be ground so that the end will
A
in the fork slot.
do the work. In some cases the guard pin
by forcing
it
hammer
very light tap with a small
may
fit
will
be lengthened
further through the piece in which the pin
is
In this case, however, the pin could not be length-
placed.
ened, and, besides, the crescent in the safety roller
was
rather wide. After flattening the guard finger the sides were-
stoned to provide the necessary guard freedom. safety tried
test,
and
the
all
comer
tests
The guard
safety test, and the curve test
were found
satisfactory.
were
The banking
pins were opened for slide.
Adjustment
2.
— correct Guard freedom — excessive Corner freedmn — excessive
Drop
When pallets
lock
the guard test and the
comer
would recede from the tooth
test
to such
were
tried the
an extent that
the impulse faces of both tooth and pallets would
show
A PRACTICAL COURSE IN HOROLOGY
118
the safety locks did not function on
some
contact; that
is,
of the teeth.
Since the drop locks were correct the excessive
guard and corner freedom suggested that the error was that
The
of a short fork.
guard
and corner
test
lever test
was therefore stretched and the
were again
be well
It will
tried.
to state at this time that the stretching should be done a verylittle
at
a time, frequently making use of the
stretch a lever, place a small, flat- faced tool
it
sides
becomes bent
If the lever
during the act of stretching, turn it
in the staking
Using a punch with
and lay the lever thereon.
flattened, lightly tap the lever.
give
stump
To
tests.
over on the stump and
another very light tap, using the same punch. Having
found the guard and corner
tests satisfactory after stretching
the lever, the banking pins are opened for slide.
Adjustment
3.
â&#x20AC;&#x201D;
Drop locks deep Guard freedom satisfactory
â&#x20AC;&#x201D; Corner freedom â&#x20AC;&#x201D; satisfactory
Since the drop locks were deep, the
first act
was
to
move
It
was found
after rebanking to the drop that the roller jewel
would not
in both pallet stones
and rebank to the drop.
The
pass in and out of the fork. position a
little
nearer to the balance
balance, the corner test
was found
to
was
from the
tried
staflf.
was
reset in a
Replacing the
and the comer freedom
be correct, but when trying the guard
guard freedom was found.
ment of the
roller jewel
The guard
the curve test were tried and
no
This example being an escape-
single roller type, the
roller table.
test
all
guard pin was bent away test,
the
were found
which the banking pins were opened for
comer
test,
and
satisfactory, after
slide.
ESCAPEMENT ADJUSTING Adjustment
119
4.
—
light Drop locks none Guard freedom
— Corner freedom — faulty
Since the drop locks were light the
This made
the drop lock.
pins to a
it
first act
was to increase
necessary to spread the banking
new banked-to-the-drop
A
position.
proper guard
freedom and safety lock were found when trying the guard but
test
found
when
was
the corner test
tried the
and the locking was not safe on
to be excessive
Examination showed that the
of the teeth.
tipped slightly toward the
staff.
The
in a position parallel with the staff
As
a
tests
were
slide
was added.
final
and
tried
was
and the corner
all
jewel
roller
roller jewel
again tried, this time showing the correct safety lock.
freedom was
test
reset
was
comer freedom and
check-up, the guard, comer, and curve
all
were found
satisfactory, after
which
Adjustment 5. Drop locks
— deep
Out of angle
When
banked to the drop the escapement showed too much
guard freedom on the side of the receiving tically correct
To
pallet
and prac-
freedom on the side of the discharging
correct the deep lock
and
to equalize the angular
pallet.
motion
of the lever from the line of centers, the discharging pallet
was moved
in.
The escapement was again banked
and the guard and corner
tests
were
tried,
to the
drop
showing too much
guard and corner freedom, also a complete absence of safety lock.
The drop
was assumed
locks were considered passable, so the error
to be that of a short fork.
The
lever w^as
A PRACTICAL COURSE IN
120
HOROLOGY
stretched and the guard and corner tests were tried, showing satisfactory guard
and corner freedom and safety
banking pins were opened for
Adjustment
lock.
The
slide.
6.
—
Drop locks satisfactory Out of angle Drop and shake close outside
—
The drop
locks being practically correct, the
to correct the condition of out of angle.
was
As
first
act
was
the out of angle
with the access of freedom on the side of the
slight
discharging pallet, the lever was bent in the direction toward the receiving pallet.
After banking to the drop and repeating
was found equal with regard
the several tests, the lever
the corner
freedom, but the drop was
condition being that of close outside.
by bending the reason
it
lever, the
draw was
inequal,
still
It will
the
be noted that
increased,
was decided that the receiving
to
and for
this
should be
pallet
tipped toward the pallet staff to equalize the drop.
This was
accordingly done and a test for draw followed, showing a satisfactory satisfactory.
condition.
All
The banking
Adjustment
tests
were
tried
and
found
pins were opened for slide.
7.
— correct Guard freedom — none Corner freedom — none
Drop
locks
After banking to the drop,
this
any guard and corner freedom. correct
it
was reasoned
escapement did not show
Since the drop locks were
that the lever
was too
long.
The
correction consists of grinding back the horns of the fork.
ESCAPEMENT ADJUSTING This
done by
is
which
Using
is
fitting to the lathe
turned to
oilstone
fit
121
an iron wire, part of
the curve of the horns of the fork.
powder and
oil,
the horns are ground
by-
holding the lever with a pair of cutting pliers against the iron wire.
Frequent applications of the corner
test
while
grinding prevented any possibility of overdoing the correction.
After grinding and polishing, the several
The banking
very satisfactory escapement action.
opened for
8.
— satisfactory
Condition of escapement
— guard pin jams against
In this example
we haye
roller table
single roller type of escapement.
After banking to the drop, the corner
found satisfactory. pin would
pins were
slide.
Adjustment Error
showed a
tests
jam or
When stick
the guard test
test
was
on the edge of the
was
tried
and
tried, the
guard
roller table.
This
error, responsible for frequent stopping, occurs occasionally in single roller escapements, but in double roller escapements
only
when
in the
the guard finger
is
The correction turning down and repolish-
loose or bent.
above example consisted of
ing the edge of the roller table and advancing the guard pin. All tests showing satisfactory conditions, slide
and the watch proved
Adjustment
to be
was added
an excellent timekeeper.
9.
— deep
Drop locks Out of angle
Draw
— wanting on both
pallets
This escapement was out of angle, with the excessive
guard freedom on the side of the receiving
pallet,
and since
A PRACTICAL COURSE IN HOROLOGY
122
the drop locks were deep and the
reasoned that
moving
all
draw was
was
it
by
faulty conditions could be corrected
The
discharging pallet.
in the
deficient
was accordingly moved
in
discharging pallet
and after rebanking
to the
drop
a thorough examination showed that the drop locks were correct; the lever's angular motion
was equal and the draw was should be remembered.
from the
line of centers
This example
satisfactory.
Errors of
frequently and the correction
is
this
kind occur quite
easy and the results are
certain.
Problems i.
What
2.
Define drop lock.
3.
State in degrees the correct
4.
What
5.
How
6.
Define draw.
7.
How
8.
Define drop.
9.
How
meant by "banked
is
to the drop" ?
amount of drop
lock.
meant by "out of angle"?
is
do you correct out of angle?
do you examine draw?
do you examine drop?
10.
Define shake.
11.
14.
What is the lift? What are the characteristics of a good action of lift? What is meant by the expression "loss in the lift" ? On what type of escapement is the loss in the lift greatest?
15.
State in degrees the total angular motion of the lever
12.
13.
escapement
is
when
the
banked to the drop.
16.
Should a watch run when banked to the drop ?
IT.
In what manner do you go about making the guard safety
test ?
corner safety test? curve test? 18.
What
is
the purpose of the guard safety test? corner safety
test? curve test?
ESCAPEMENT ADJUSTING What do
19.
the above tests aid in determining,
123 if
the drop locks
are correct ? 20.
Define
slide.
21.
When
is
22.
Give the specifications for a correctly designed escapement,
without
slide,
added?
slide
secondly with
first
slide.
altering the banking pins change the drop lock
23.
Does
24.
Define total lock.
25.
Does altering the banking pins change the total lock ? How do you correct an escapement in which the drop locks are
26.
correct but there
What
27.
is
is
?
an excessive guard and corner freedom ?
the error in an escapement that has a deep lock yet
the guard and corner
freedom are satisfactory?
If the drop locks are light and the guard and corner tests
28.
no freedom, what order
is
show
the correct procedure to put the escapement in
?
The drop
29.
locks are deep and the escapement
is
out of angle
with no guard and corner freedom on the side of the discharging pallet.
There
is,
however, too
the side of the receiving pallet. this
escapement ?
much guard and
How
corner freedom on
would you go about correcting
Part II
CHAPTER SEVEN Cleaning and Oiling Two METHODS that
we
are used in cleaning watches.
first
method generally referred
shall consider is the older
to as the
The
hand method. The second involves the use of the
cleaning machine.
The Hand Method In using the hand method we proceed as follows taking the
movement apart
string the larger pieces
loop, place the pieces in benzine, benzole, or
:
After
on a wire
any other good
cleaning preparation for several minutes.
Remove and wash
pieces in hot water, using castile soap
and a soft brush.
Rinse in clean water, dip in cyanide of potassium, rinse again in clean water,
immerse
The same treatment
is
and dry
in alcohol,
in
warm
sawdust.
given to the wheels and other small
pieces that can be strung on the wire loop, but separately,
The other small pieces jewels, may be held against
after the plates have been cleaned.
such as the pallet fork and the
a piece of hard pith or cork with a pair of tweezers especially
prepared for the purpose and brushed thoroughly with a fine
toothbrush previously dipped in benzole.
After being
brushed, the pieces are dipped in alcohol and allowed to dry
on a sheet of watch paper. separately.
The
The
usual method 124
is
balance must be cleaned
to dip the balance
first in
CLEANING AND OILING
125
benzole, then in water followed by cyanide, again in water
and
finally in alcohol,
The
parts are
now
after which
it
is
dried in sawdust.
dry and the jewels should be rubbed with
two pieces of pegwood, one which has been pointed so as to to
go through the holes and another that has been shaped fit
the cups of the jewels.
The watch having been
cleaned, the assembling
For example, the main spring
barrel with clock
oiling
Certain parts are oiled as the watch
are next in order.
put together.
and
is
oiled in the
The winding mechanism,
oil.
is
the escape
wheel, the pallet jewels, and the hole jewels where cap jewels are used in connection are also oiled in the process of
assembling.
The
train
is
oiled after the
watch
is
assembled,
The
cannon pinion.
also the center post that carries the roller jewel is not oiled.
The
Watch-cleaning Machine
The newer method of
cleaning watches with the cleaning
machine has some advantages.
Instead, an especially prepared cleaning solution
cyanide. is
eliminates the use of
It
The
used, together with water and a drying solution.
machine
is
particularly satisfactory for the cleaning of small
pieces like the pallet fork, the jewels,
and screws and has the
further advantage of eliminating the use of sawdust. Briefly, the
basket.
procedure
is
as follows
:
Place the parts in the
There are provided several small spaces for the
small pieces and one large space for the plates.
Lower
the
basket into the jar containing the cleaning solution and allow the motor to run for several minutes at a moderate speed.
Throw
off the cleaning solution
ciently to clear the
solution.
by raising the basket
Lower
sufifi-
the basket in a jar
A PRACTICAL COURSE IN HOROLOGY
126
containing water and rinse off the cleaning solution.
Next,
lower the basket in the drying solution and run the motor as Finally, allow the basket to spin in a receptacle
before.
containing a lighted electric light bulb for a quick drying of the watch parts.
Thus
the cleaning job
is
completed.
Problems 1.
Is
it
important that the jewels should be cleaned with peg-
wood? 2.
3. 4.
What parts of a watch do you oil? What parts should not be oiled ? Name some advantages in using the
cleaning machine.
PART
III
ADJUSTING
Part III
CHAPTER ONE
Preliminary Notes on Adjusting There
is
a greater
demand
for watches of accurate time-
keeping qualities today than there was years ago.
The
rail-
roads require that their employees' watches run within certain close limits
and the complexity of modern
need for greater accuracy
also.
close timing can be assured, a
ing
To
life
has shown a
repair watches so that
working knowledge of adjust-
necessary.
is
The
who
horologist
has never been concerned about the
theory and practice of adjusting has missed the real fascination
Aside from gaining
and satisfaction of watch work.
pleasure for himself, the repairman
of adjusting to his
work
will
who
applies the principles
win the respect of
and the sincere appreciation of
his
employer
his customers.
Adjusting consists in the execution of such manipulative operations of the balance spring and other parts as to cause a watch to function uniformly, the rate being within well-
defined limits under various conditions. urally divided into three branches:
(2)
isochronal adjusting, and
(3)
Adjusting
analysis
adjusting
is
all
temperature adjusting.
three are inseparable
completed. 128
nat-
(1) position adjusting,
These require independent methods of correction but final
is
when
the
in the
work of
PRELIMINARY NOTES ON ADJUSTING
129
General Observations Before considering the more complex problems
it
will be
must be as
well to outline briefly those conditions which
work can be attempted.
nearly perfect as possible before
THE MAIN TRAIN Close position and isochronal rating cannot be expected
Extreme
unless the
main
variation
often caused by defects in any of the train wheels
and
A It
is
train
is
in first-class condition.
especially in the center wheel
correct is
amount of end shake and
well, therefore, to
movements with regard
A
to train
and balance pivots should be round and pivot that
is
not perfectly round will
insert
is
round, but jewels
is
in
a
triangular piece,
we change
the jewel for
not round and repeat the experiment, the result
will be different.
and
The
steel
the
the jewel properly, will turn in the hole as perfectly
as a well-rounded pivot, but if
one that
To show
a three-cornered piece of
jewel that has a perfectly round hole. if it fits
also, the
slightest degree.
frequently do not have perfectly round holes. plainly,
important.
freedom and note,
function fairly well in a jewel hole that
effect
is
examine a number of high-grade
winding the mainspring even to the
well polished.
side shake
barrel.
wheel after the train runs down when
recoil of the escape
All train-wheel
and mainspring
will not turn.
The triangular piece will become wedged The effect exists in a lesser degree when
an imperfect jewel and an out-of -round pivot are used together, yet the
combined action of the two
affects the time-
keeping qualities of a watch.
Furthermore,
impossible to poise the balance
if
the
pivots of the staff are not round, and in this connection
we
it
is
A PRACTICAL COURSE IN HOROLOGY
130
recommend the
pivot
polisher
on
occasions where
all
This lathe attach-
balance pivot needs reducing or polishing.
ment
forms the pivots
(assuming the machine
perfectly
work quickly and with a
the
round and cylindrical
properly adjusted), and
is
a
it
does
factorylike polish.
INFLUENCE OF THE LEVER ESCAPEMENT ON THE ADJUSTMENTS The impulse communicated
to
the balance through the
escapement should take place at the moment when the balance spring
is
at its state of rest, that
spring
the
is
is,
moment when
at that
under no tension whatsoever.
This ideal
condition would permit the balance and spring to perform arcs of vibration in the
its
and
spring
same time
would perform these
mechanical means at one's
that a free balance
However, the
arcs.
disposal
to
keep the balance
vibrating does not meet the above requirements and one
is
obliged to take account of the following laws. 1.
An
impulse delivered
the point of rest 2. its
An
-will
to a balance or
pendulum before
accelerate the vibrations.
impulse delivered to a balance or pendulum after
point of rest will retard the vibrations.
This principle can be easily demonstrated with a simple
pendulum. its
Impulse given
point of rest causes
quickly than
if it
it
to a
pendulum before
it
reaches
to arrive at the point of rest
were acted upon by gravity
alone.
more Given
impulse after reaching the point of rest results in driving the
pendulum
farther, resisting the force of gravity
no particularly accelerated
rate, if any.
Hence a
and
at
retardation
takes place and the greater the distance the impulse takes place after the point of rest, the greater
is
the retardation.
PRELIMINARY NOTES ON ADJUSTING
Now
consider this factor in relation to the lever escape-
The
ment.
131
total
angular motion of the lever
The
allowing for 2 degrees of lock.
is
10.5 degrees,
relationship between
the acting length of the lever and the roller jewel radius 3.5 to
The
1.
would be
3.5
this figure
total lifting angle or contact
X
with the balance
Placing one half of
10.5 or 36.75 degrees.
on either side of the
is
we would
line of centers
have 18.375 degrees. However, the locking must be removed
from
that
contact before the line
portion of
(point of rest).
Thus
the line of centers
would be 18.375 â&#x20AC;&#x201D;(3.5
degrees. full
The impulse
amount or 18.375
of
centers
the impulse communicated before
X
after the line of centers
2)
=
11.375
would be the
degrees.
to the
above analysis a retardation would result
for the short arcs.
Further retardation occurs because of
According
the unlocking action, which
is
free motion of the balance.
Hence
carefully adjusted escapement in the fine position
a serious resistance to the
is
it
is
clearly seen that a
of the utmost importance
and isochronal rating of a watch.
WEIGHT OF THE ESCAPE WHEEL AND PALLET FORK The
escape wheel should be as light as possible consistent
The
with proper firmness.
sluggishness of a heavy escape
wheel directly increases the inequality of the impulse between the receiving
and discharging
of the draw and the
The
lift
on the
lever, too, should be
was formerly the
pallets pallets.
made
as light as possible.
It
practice of manufacturers to add a counter-
poise to the lever, supposing that close position rating.
strated that this
owing to the inequality
is
it
was necessary
to secure
Research into the problem has demon-
not necessary; in fact,
that lightness of the lever
is
of
much more
it
can be shown
importance.
The
A PRACTICAL COURSE IN HOROLOGY
132
counterpoise only gives the force at the circumference of
more work
the escape wheel
do and thus tends to make
to
the actions of the escapement and balance
more
sluggish.
MAINSPRINGS AND BALANCE MOTION
A
mainspring unwinding in a barrel generally does not
Were
take place in a concentric manner.
it
this ideal condition could be attained, there
act of
would be
Httle
coils
and a more smooth and
result.
This eccentricity in the
or no friction between the
even motive power would
possible that
unwinding varies with the type of brace or hook used
on the outer end of the
Experience has shown that
spring.
any type of hook that maintains a quarter turn of the external coil flat against the wall of the barrel gives it is
gratifying to note that
good
results
and
more and more manufacturers
are adopting some form of hook with this end in view. It is
important that the horologist use the very best main-
springs that
a good spring that
The
money can buy. is
so apparent in the position rating of a
no argument
Springs that are
superior performance of
is
watch
necessary to convince the most skeptical.
set,
even to a comparatively slight degree,
should be replaced with
new ones and
the mainspring winder
should always be used.
The proper arc of motion of the balance is 540 degrees when the watch is fully wound and lying in a horizontal position.
when a
Horologists experience a feeling of real satisfaction full
balance arc
is
attained with the fitting of the
weakest possible mainspring.
most even motive power
It
will be
is
an indication that the
maintained for the
hours of running and that there will be only a slight off of the balance arc at the
end of a 24 hours run.
full
24
falling-
:
PRELIMINARY NOTES ON ADJUSTING
How
The
to ascertain the arc of motion.
arise as to
how we
133
question
may
are able to ascertain this arc of motion.
This the eye can be trained to recognize easily and at a glance by using the following method is
at rest with the
roller jewel
between the banking
Suppose the balance
:
in the
Now move
pins.
midway
fork slot
the balance one half
of a circle or 180 degrees and stop.
Release the balance
and the force of the spring
to return to
will cause
it
its
of rest and 180 degrees farther on the opposite side. arc of motion would be 360 degrees. Again
move
its
the opposite
own power to side. The arc
and the balance
its
The arms
it
to
point of rest and as far on
of motion
will continue to vibrate
as long as the proper motive
The
the balance,
three fourths of a circle or 270 degrees, and allow
return on
point
power
is
is
now 540
degrees
between these points maintained.
moment
of the balance become visible at the
the
balance completes the arc of motion and starts in the opposite direction
time
on
when
its
return vibration.
It
is,
therefore, at that
the balance stops that
the arc of motion can be deter-
-
o
mined.
1,
With
the assistance of Figure
the
problem can be more
clearly explained in this
When
/3S^
manner
the balance vibrates 180 /^{fm^m^imt^
degrees and returns to
degrees
and continues as
on the
opposite side
arms are
â&#x20AC;&#x201D;that
visible at
â&#x20AC;&#x201D;the
and
degrees
tion is
360 degrees.
far is,
j^s
|
when
the
180 degrees arc of
When
^a^^^Mi ^
mothe
|
270" Figure
1
**
— A PRACTICAL COURSE IN HOROLOGY
134
balance vibrates 225 degrees and returns to continues as far on the opposite side are visible
first at
—
that
degrees and
when
is,
the
arms
225 degrees and 45 degrees and on
its
return vibration at 135 degrees and 315 degrees (forming a cross at right angles)
When
—the
when
the
arms are
the arc of motion
The
horologist
positions
and
if
is
on the opposite side
far
540 degrees. should examine the balance arc in
the motion
is
down.
made before any adjustment Note carefully
any difference between the arcs of
These positions should be
equal.
of pendant up, pendant right, pendant
The
down.
all
faulty in certain positions the
to position or isochronism is attempted. is
—that
270 degrees and 90 degrees
visible at
necessary corrections should be
there
450 degrees.
is
the balance vibrates 270 degrees and returns to
degrees and continues as is,
arc of motion
dial
up and
if
dial
Note
also the arcs
left,
and pendant
arcs for the vertical positions should be the
same although somewhat shorter than those for the two horizontal positions,
owing
to the increased friction
on the
balance pivots.
The
arc
of
motion should never be longer than 540
Experience has shown that an arc longer than the
degrees.
above figure produces a very fast rate for the
first
few hours
of running, after which time (the arcs becoming shorter) the watch functions at
its
normal
rate.
THE POISE OF THE BALANCE One
of the most
positions
is
common
causes of variation between
want of poise of the balance.
The
horizontal
positions are not affected but the error in the vertical positions is
considerable.
The
extent of the variation in the rate
in proportion to the extent of the error in poise.
is
PRELIMINARY NOTES ON ADJUSTING
on the lower side of the balance the watch will lose when the arc of motion is
// the excess of weight
when
135
at rest,
is
greater than 450 degrees, and will gain
when
the arc is less.
is
on the top side when the balance
is at
rest, the result will
be reversed and the watch will gain
when
If the weight
the arc of motion is greater tlmn 450 degrees
when
will lose
the arc is less.
Nature of error due to want of that the excess of weight
when
and
at rest.
Let us assume
poise.
on the lower side of the balance
is
Suppose the balance vibrates
at
an arc of
almost 360 degrees, and in doing so the weight will stop near
The
the top of the balance. the balance to
its
point of rest will receive an added energy
in that of gravity acting
the spring will return to
when
than
force of the spring in returning
This means that
on the weight.
its
point of rest a
little
more quickly
acted upon by the force of the spring alone.
Now
assume that the weight, after having reached the bottom, continues the arc on the opposite side. acting on the weight
is
The
force of gravity
an added resistance to that of the
spring; in other words, the result of an added weight in effect, the
same as
arc will be performed
Now and
if
is,
a stronger spring were used and the
more
quickly.
suppose that the motion
is
increased to 540 degrees
in vibrating to this extent the
weight starts from
its
point of rest at the bottom and turns three quarters of a circle
and stops
at right angles to
the center of the balance.
a vertical
The
line
drawn through
force of the spring will
encounter a resistance due to gravity acting on the weight as
it
starts
upward toward the
top,
and after reaching the
top and starting downward, the force of gravity force
downward.
The
effect
is
an added
would be a retardation during
A PRACTICAL COURSE IN HOROLOGY
136
the
first
portion of the path and an acceleration during the
latter portion to the extent that, for arcs
450 degrees the watch that at
will lose.
some point near
would seem, therefore,
It
450 degrees these forces would
Some
counteract each other. at
to
above approximately
authorities place this figure
444 degrees. Poising the balance.
and
Place the balance on a poising tool
start the balance in motion.
During the time
it is
rotating
hold a small compass as near as possible to the circumference of the balance so as to ascertain whether or not netized.
It
is
useless
balance; hence the
even the slightest
The
first
bit of
mag-
it is
to
attempt to poise a magnetized
act
is
to demagnetize
it
if it
shows
magnetism.
balance having been demagnetized and found satis-
Having located the
factory, proceed with the poising.
tion of the heavy point
it is
position of the regulator.
good practice to take note of the This
is
our guide
whether we should reduce the weight
add weight opposite to the heavy
amount of timing Should we
find,
after the
when
is
at the
in
deciding
heavy point or
point, thus saving a certain
watch
is
again running.
altering the weights, that the heavy
point has shifted a short distance
good progress
being made.
we may
However,
feel certain that
if it is
found that
the heavy point has been shifted to the opposite side
evident that the correction has been overdone. therefore, that in altering the weights
with caution and thereby save a
much
posi-
much
we
It
it
is
follows,
should proceed
time, besides realizing
better piece of work.
Parallel pliers with cardboard glued to the jaws are very effective for holding the balance while
the screws.
removing and replacing
PRELIMINARY NOTES ON ADJUSTING
137
MAGNETISM Magnetism
an ever-constant and insidious enemy to
The means by which a watch may be magnetized
horologists.
are so
is
numerous today
form the habit of comes
that
it is
important that the repairman
testing every
watch for magnetism that
in for regulation, examination or repair.
In testing for magnetism place a small compass not only
The
over the balance but also over the winding wheels.
mainspring being subject to magnetization as well as other steel parts,
has definite poles at the time the magnetic lines
These poles are
of force passes through the watch.
up
into countless
constant
split
numbers as the mainspring unwinds. of
alteration
the
position
relative
of
the
This poles
between the mainspring, winding wheels, and the balance helps
explain
to
the
performance of magnetized
erratic
watches.
Theory that type
An
of demagnetization.
of
electrical
alternating current
current that changes
is
direction
its
when such
current flows through a coil of
wire the poles also change.
Figure 2 shows a conception of
constantly and
an alternating current wave as the complete
wave
is
is
An
time,
and
alternating current
said to have a frequency of
cycles.
When
a
steel
rod
is
inserted in a demagnetizer
flow of alternating current will be
the current
was
suddenly cut
is left
its
off,
and the
the steel rod
poles being that of the
sent through the wire.
However,
on and the rod gradually withdrawn,
the result will be different. cycle
is
found to be magnetized,
last half cycle that if
moves through
called a cycle.
of 60 such waves per second
60
it
It will
be repolarized for every
and each successive polarization
will be
weaker than
A PRACTICAL COURSE IN HOROLOGY
138
Figure
Wave form
2.
When
the preceding one.
of alternating current
withdrawn
entirely
from the
field,
the magnetism has disappeared.
Demagnetizing a watch. The procedure in demagnetizing Withdraw a watch is much the same as explained above. the watch, keeping
it
central with the opening
a slight twist after leaving the opening.
drawal until the watch
is
it
Continue the with-
about three feet or more from the
If the first attempt fails to
demagnetizer.
and giving
remove
all
mag-
netism repeat the operation.
Magnetized
tools.
being magnetized. closely watched.
position in or
The
horologists' tools are subject to
Screw drivers and tweezers should be Avoid placing such
tools in a north-south
on the bench.
Problems 1.
Why
2.
What
should balance pivots be made perfectly round is
?
the effect of giving impulse to the balance or pendu-
lum before the point of
rest? after the point of rest?
PRELIMINARY NOTES ON ADJUSTING 3.
What
is
the effect of the lever escapement
139
on the position
rating of a watch?
on the
pallet fork of
very great importance?
4.
Is the counterpoise
5.
Does the type of fastening on the outer end of the mainspring
have anything to do with the friction between the coils? 6.
What
7.
How
8.
What
9.
If the excess of weight
when
is
the proper arc of motion of the balance
do you ascertain the correct arc of motion? is
the most
at rest, will the
540 degrees
?
common
cause of position error is
on the lower
watch gain or
when running
at
lose
side of the balance
an arc of 350 degrees ?
What
balance arc
11.
How How
do you go about poising the balance?
is
considered the neutral arc?
do you demagnetize a watch ?
?
when running
10.
12.
?
at
an arc of
Part III
CHAPTER TWO Position Adjusting The
first portion of this chapter treats on position error
as related solely to the balance spring and of the effect of
gravity which
most
coils.
is
is
such that a positive
produced.
from barrel
knows how
to
fection, there will
in
of this action
watch may be mechanically perfect
struction skill
an ever-present force acting upon the inner-
The nature
position error
A
is
to balance
make
it
may
â&#x20AC;&#x201D;and
â&#x20AC;&#x201D;that
is,
its
be as exact as
con-
human
such per-
yet, in spite of
be a variation of from 15 to 30 seconds
24 hours between some two
vertical positions
In watches that are
condition of the balance spring alone. less perfect the error is frequently as
due to the
high as 40 seconds or
more.
The Balance Spring and The
oscillation
Its Poise
of the inner portion of the spring cor-
responds very nearly to that of the collet travels three fourths of
a
collet
circle,
center travels nearly an equal distance.
;
when
the
first coil in
the
that
the It is
from the
movement ceases coils are marked
is,
further evident
that each of the several coils, as they tend to distant
Error
become more
center, will travel a shorter path until the
altogether at the regulator pins. in a straight line
140
from
If the
collet to regulator
POSITION ADJUSTING
141
one would readily observe the distance traveled by the
pins,
several coils
and the extent of
their path
under different arcs
of motion. It is
impossible to poise a spiral spring.
at once evident that
it is
portion of the spring,
Therefore
the oscillation of the unpoised inner
when
acted upon by the pull of gravity,
that causes position error in the vertical positions.
ment
how
as to
this
it is
works need not be repeated
A
state-
here, for
the analysis given in the preceding chapter relative to the poise error of the balance, applies to this condition also.
However, motion
slightly
result,
varied
effects
under different arcs of
due to the fact that the greater mass of the
unpoised inner portion of the spring vibrates in a shorter arc
than does the balance proper.
Experimental demonstration.
command
of every horologist
run them,
first
is
with the figure
1
A
demonstration at the
to take several watches
up, and following with the
figures 2, 3, 4, etc., continuing the experiment dial
with
all
and
around the
figures up, running the watches in each of the
12 positions for 24 hours and taking note of the rate in each position.
If
an
electric
timing machine
is
available the
experiment can be made most conveniently and
in
a very
short time.
Table
1
shows the
result of an experiment as stated above,
using four popular makes of American watches. All watches
were in excellent condition with balances perfectly poised, fitted
with theoretically corrected overcoils, and the grades
ranged from 17 jewels to 21 jewels. the balance of
all
The
arc of motion of
watches was about 540 degrees when fully
wound and more than 450 degrees after 24 hours of running. In watch Number 1 the rate was fastest at the time when
142
A PRACTICAL COURSE IN HOROLOGY
the figure
11
was up
;
in
watch Number 2 the rate was
fastest
when the figure 3 was up. The watches Number and Number 4 had definite fast positions also, and in all
at the time
3
watches the slow position was opposite or nearly opposite that of the fast position.
TABLE
1
POSITION ADJUSTING
Figure
3.
2.
Proper pinning at the
Reduce
collet.
Figure
4.
143
Proper pinning at the collet
the natural error by the application o,
correct
terminal curves both outside and inside. 3.
Neutralise the effect of the natural error by counter-
poising the balance.
These corrections
will
now be
considered In the order
stated above.
The proper pinning
at the collet.
When
fitting
new
balance springs to pocket watches, certain pinning points
should be observed expected.
Figures 3
upward
as
if
the best position rates are to be
The proper pinning at and 4. The first half of it
the collet
is
shown
in
the innermost coil tends
leaves the collet in the direction of pendant up.
A PRACTICAL COURSE IN HOROLOGY
144
producing a fast pendant-up
It
rate.
does not matter
if
the
spring tends to the left as shown in Figure 3 or tends to the
shown
right as
in Figure 4, for
can be readily seen
it
that,
in either case, the middle of the first half of the innermost coil is
the spring
pinned as stated above, the pendant-right and pendant-
left positions
will
have a slower but a nearly equal
provided the balance spring concentrically.
show up only watch
The
little
it
is
rate,
properly centered and vibrates
greater part of the natural error will
pendant-down
in the
in practical
position,
of
When
stands in the direction of pendant up.
usage
is
position,
seldom
and since a pocket
ever subjected to this
if
follows naturally that the pendant-down error
is
importance.
Reducing the natural
error.
It
was
stated in the first
portion of this chapter that finely constructed watches vary
from 15 positions
much to be
to
30 seconds
in
24 hours between some two
and watches that are
as 40 seconds and more.
more than 30 seconds
variation
is
less perfect
vertical
would vary as
If the natural error
is
shown
24 hours, the excessive
in
due to want of perfection of the inner terminal
of the spring.
A slight eccentric motion at the inner terminal
will cause a greater variation than
spring were perfectly true.
Thus
it
would be the case is
if
the
clear that the balance
spring should always be faultlessly trued at the collet and equal attention should be given to both the
The Breguet type balance spring on would now be natural for one to inquire
flat
and the round.
position error.
It
as to the effect of
the Breguet spring with correct terminal as compared with the ordinary
flat
spring on position error.
Experiments
have demonstrated that the Breguet spring does reduce the
POSITION ADJUSTING
145
variation in the vertical positions, but only to a small degree,
proving that the position error
is
due primarily
to
the
oscillation of the center of gravity of the inner portion of the
spring.
Table 2 shows the results of an experiment using both the
flat
and Breguet
example was an 18 spring.
The
springs. size,
15- jewel grade, fitted with a flat
column of the
rate with
and the second column shows the
rate with
the
flat
the
same spring after
correct terminal.
24 hours.
selected for this
shows the
first
spring,
The watch
it
table
was made over
The watch was run
into a in
Breguet with
each position for
:
A PRACTICAL COURSE IN HOROLOGY
146
Usually just a slight touch of the poising
rate will result.
saw in
will
reduce the natural error as
much
as 5 to 10 seconds
24 hours.
Use of the Regulator Pins The
in Adjusting
condition of the regulator pins play an important
In
part in the position rating of a watch.
may
opening or closing the pins as the case possible to
fact,
by
slightly
require,
it
is
bring the horizontal and vertical positions in
close agreement.
Let us suppose, for example, that the regulator pins are
opened
slightly
and the
first coil
We
between the pins.
have
of the spring vibrates equally
literally
made
the active length
of the spring longer and the watch will go slower.
It also
changes the rate between the long and short arcs. The effect
can be explained in this
way
Suppose that the balance degrees and the pins.
first coil
is
vibrating at an arc of 180
of the spring barely touches the
For arcs below 180 degrees, the
spring will
active length of the
commence very nearly from
the arc of motion
is
the stud.
and the
effect will
if
increased to 540 degrees, the active
commencing more
length of the spring will be shortened,
nearly from the pins.
Now,
This will make the long arcs go faster
vary
in
proportion to the changes taking
place in the arc of motion.
Suppose now that the pins are open, but instead of the first coil
first
coil
of the spring vibrating equally between them, the
Assume that it coil away from the
leans against one of the pins.
requires an arc of 360 degrees to
pin against which
it
leans.
lift
the
It is plain that for arcs
360 degrees the active length of the spring
will
below
commence
:
POSITION ADJUSTING from the
147
and for arcs above 360 degrees the active commence more nearly from the stud. This
pins,
length will
condition will
make
the long arcs go slower, or, in other
words, opposite to that in the former instance.
Thus
be seen that the condition of the regulator pins
may
cause of
many
an
intelligent
the quickest and simplest
in the vertical positions. is
The
vertical is
positions
always shorter
practical use of the regulator
stated in the following rules
If the regulator pins are closed and the watch gains
1.
in
is
means of correcting the variation
because of the fact that the arc of motion
pins
be the
manipulation of the pins
between the horizontal and
rate
can
of the disorders in the performance of watches.
It is also true that
in the
it
the
pendant-up position, a slower pendant-up rate
is
obtained by opening the pins. If the regulator pins are open and the watch loses in the pendant-up position, a faster pendant-up rate is obtained 2.
by closing the
The coil
pins.
spring should be so adjusted that the vibration of the
between the pins
is
equal
;
otherwise, the coil will strike
one pin with more force than the other, and the result will be very different from that stated in the above rules. Also in spreading the pins, the vibration of the coil
between them
should be very slight and discernible only with a powerful
The
glass.
pins should never be spread
more than enough
mean rate 3 seconds an hour. If spread beyond amount the watch is apt to become a very unreliable
to slow the
that
timepiece
;
in other words, position adjusting
lation of the regulator pins
extent.
by the manipu-
can be practiced only to a limited
A PRACTICAL COURSE IN HOROLOGY
148
Adjustment
Horizontal Positions
to the
on the
Effect of manipulating the regulator pins
We
zontal positions.
hori-
have seen that the rates between
dial
up and pendant up can be equalized by the manipulation of Should we
the regulator pins.
alter the pins to secure the
up and pendant up, we could
desired results between dial
expect a change in the rate between the horizontal positions
Often the horizontal
also.
they are reversed.
improved; sometimes
rates are
This would suggest that the adjustment
â&#x20AC;&#x201D;that
made last up and pendant up are
to the horizontal positions should be
the corrections for dial
After a
little
in the rate is
reflection
wise
it
dial
is
after
satisfactory.
evident that the difference
due to the anisochronism of the balance spring.
The manipulation tween
it
is,
of the pins not only corrects the rate be-
up and pendant up, but more often than
improves the isochronal rate
by running a given watch
other-
This can be shown
also.
in the position of dial
up for 8
hours at an arc of 540 degrees and taking note of the rate
and then running 360 degrees.
it
again for another 8 hours at an arc of
If the
rate
is
slower
when running
at
360
degrees the pendant-up rate will usually be slower. Occasionally there are exceptions.
Correction of errors in the horizontal positions. Errors
between the horizontal positions come generally under the
head of
frictional errors
and have
the arc of motion of the balance.
even 4 seconds laid to
Is
unimportant.
rough pivots,
to
A
do with changes
in
variation of 2, 3, or
Extreme
variation can be
dirt or thick oil, hole jewels that are
too small or too large, pitted cap jewels, balance pivots not the same size, or a balance spring out of
flat.
As
a rule the
POSITION ADJUSTING fast position takes the shorter arc,
which would suggest that
the position producing the fast rate
Assuming
correction.
149
that the staff
is
the one that calls for
and jewels are as nearly
perfect as an inspection with a strong glass can determine, a
general rule for the correction of the rate in the horizontal positions reads as follows
:
Round
slightly the
lower pivot in
the position that is fast.
Problems possible to poise perfectly a balance spring?
1.
Is
2.
What
it
is
the natural error
position rating of a
?
it
affect the
watch ?
2.
What
4.
Does the outer terminal of
is
In what manner does
the proper pinning at the collet
?
the balance spring have a greater
or smaller effect on the position rating of a watch as compared with the inner terminal 5.
Can
?
the regulator pins be of use in adjusting a watch to posi-
tion? Explain. 6.
What
positions
?
are the usual causes of position error in the horizontal
:
Part III
CHAPTER THREE
Adjustment to Isochronism The adjustment
to isochronism is that
adjustment which
has to do with the maintaining of a constant rate over a definite period of time.
Absolute isochronism
to attain because of several factors
is
impossible
which are inherent
in the
balance spring and for which there are no practical remedies.
A
pendulum
equal time.
will
Start a
make
the long and short vibrations in
pendulum
in motion, traveling over a
As
given space in a given time.
the motion falls
off, it will
be observed that the time consumed in each vibration does not change.
A
slower or faster rate can be produced only
by lengthening or shortening the pendulum. The pendulum is
in reality a
falling
body and the laws which apply
falling bodies apply to the
pendulum
also.
to
Therefore adding
or reducing the weight of the pendulum does not affect the
time of vibration, for any change
with
it
made
in the
mass
carries
a proportional force in that of gravity.
Adding
mass of the balance varies the
to or reducing the
rate of vibration, for the strength of the balance spring does
not change.
There are three
factors
upon which the time
of the vibration of the balance depends. They are 1.
2.
The weight of the balance. The diameter of the balance. 150
ADJUSTMENT TO ISOCHRONISM 3.
The
As
already stated, the balance spring
strength of the balance spring.
more important disturbing of watches. first
151
Of
is
the cause of the
factors in the isochronal rating
these disturbing factors, our attention will
be directed to the problem of isochronism as affected by
varying the total length of the spring.
The Length
of the Balance Spring on Isochronism
In every balance spring there
is
a certain length in which
the long and short vibrations are practically isochronal. if this
length is ascertained and
by whole
coils,
we
the short arcs will
Now
spring shorter
'tnake the
go faster; and
if
we make
the spring longer by whole coils, the short arcs will go slower. It will
be observed that the shortening or lengthening
done only by whole
coils.
The reason
in the following statement.
some portion of a
coil
for this
is
explained
If the spring is shortened
and not by whole
would take place which would
coils,
alter the isochronism.
is
one that
is
from the one now under discussion and
A is
For coil
cause the short arcs to produce a losing rate instead of
a gaining rate. This problem
more
by
another effect
example, the shortening of the spring by one half of a
may
is
in detail in the
spring that
is
distinctly separate it
will be treated
next section.
practically isochronal as far as the length
concerned usually consists of about 13
coils.
Springs
supplied by the manufacturer are correct for length.
The
thought to remember from that which has been stated above is
that in fitting a
new
spring, the spring should not be
shortened excessively in timing, for in so doing the isochronal rate
is
affected.
:
A PRACTICAL COURSE IN HOROLOGY
152
The Flat and Breguet Balance Spring on Isochronism
The
flat
spring.
If
one will examine a
watch during the time the balance observed that the vibration
is
in the spring,
in motion,
is
This
is
not
all
will be
the eccentric
however, for a similar motion
takes place opposite the inner terminal, although visible to the eye.
it
wholly on one side and on the
side opposite the regulator pins.
motion present
spring in a
flat
These eccentric motions
it
is
less
affect the iso-
chronism because of several conditions. The principal ones are:
(1)
a constant oscillation of the center of gravity,
(2) a persistent pushing and pulling at the balance pivots,
and (3) the
effect of
torsion, with
which
section
this
is
particularly concerned.
Action of the
flat
balance spring.
Torsion
is
a circular
impulse which takes place at the innermost coils of the spring.
The
result is a retardation or
an acceleration, de-
pending on the relative positions of the two eccentric motions as the balance vibrates.
The anisochronism thus produced Such
can be varied by altering the length of the spring. alterations, of course,
change the angular distance between
the inner terminal and the regulator pins, and
it is
this
change
of angular distance that decides the rate between the long and the short arcs.
The laws governing
the isochronism as con-
cerned with the above statement are as follows 1.
and coils,
2.
When
the angular distance between the inner terminal
the regulator pins stands at even coils, that
is,
whole
the short arcs gain.
When
the angular distance between the inner terminal
and the regidator pins stands the short arcs lose.
at
even
coils,
plus half a
coil,
ADJUSTMENT TO ISOCHRONISM
Figure
3.
When
Figure
5.
153
6.
the angular distance between the inner terminal
and the regulator pins stands three fourths of a
coil,
at
even
the long
coils
plus one fourth or
and short arcs are more
nearly isochronal.
Let us assume that the arc of motion of a given balance
360 degrees, as an example of a short pinned at even
coils,
opposite directions.
is
If the spring is
arc.
the eccentric motions will stand in
According to rule
produces a
this
1,
gaining rate as compared with the long arcs.
This can be
explained by reason of the fact that the eccentric motion of
(when wound up)
the outermost coils exerts a force direction
of the arrow A,
motion of the innermost
Figure
coil exerts
5,
in the
while the eccentric
a force in the direction of
the arrow B, and since these forces are in opposite directions, there
is
a tendency toward acceleration as the arcs become
shorter than 540 degrees and the degrees.
maximum
is
reached at 360
In unwinding, the forces are reversed but their
relation to each other
If the spring
is
is
the same.
pinned at even
coils plus half
eccentric motions will stand in the
opposite the regulator pins.
same
According
a
direction,
coil,
the
namely:
to rule 2, this pro-
duces a losing rate as compared with the long arcs. Since the forces of the eccentric motions are in the
same
direction,
A PRACTICAL COURSE IN HOROLOGY
154
Figure
6,
there
the balance
may
and
resistance or divergence of forces
is less
vibrate a
little
farther; hence a retardation
takes place. If the spring is
pinned at even
three fourths of a
coil,
coils plus
one fourth or
the eccentric motions will stand at
right angles to each other, the effects stated in rules will
1
and 2
be neutralized, and the watch will function at a more
nearly isochronal rate. practical
usage,
changing and
The
the
Of
course,
when
the watch
motion of the balance
is
is
put to
constantly
this fact considerably complicates results.
effect of torsion
should not be confused with that of
the oscillation of the center of gravity, for the latter
function that
is
distinctly different
part in producing an anisochronism.
is
a
and plays only a small
The
effect of torsion is
by far the most disturbing element and the only way its effect may be reduced, aside from varying the terminal pinnings,
is
the application of the most perfect terminal
curves, both outside and inside.
Reducing the isochronal
error.
The
superior perform-
ance of the Breguet spring in the attainment of isochronism is
the reason for the passing of the
analysis of the
flat
in
spring.
The above
spring would at once suggest that
possible to vary the isochronism coil of the
flat
it
is
by manipulating the over-
Breguet spring so as to throw the eccentric motion
some desired
direction.
That
is
correct reasoning;
how-
ever, a spring that produces concentric vibrations will attain close
enough isochronism
same time
in
most watches while
at
the
realizing the best position rating in the vertical
positions.
Modem
watches are built with a better design and pro-
portion of parts than the older models and the correction of
ADJUSTMENT TO ISOCHRONISM isochronism by
means of
seldom necessary.
altering
However,
if
a
correct
155
terminal
is
the most perfect terminal
curves do not produce the desired results, the following rules for altering the overcoil 1.
may be
used.
If the short arcs are slow, bring in part of the body of
the spring
and add
it
to the overcoil.
If the short arcs are fast, take part of the overcoil
2.
and move
it
back into the body of the spring.
Problems
What
1.
coils
is
the effect of shortening a balance spring
by whole
on the isochronal rating of a watch?
What
2.
What
3.
In what manner do you alter the overcoil to accelerate the
is
torsion ?
are the effects on a
flat
balance spring?
short arcs? 4.
arcs?
In what manner do you alter the overcoil to retard the short
Part III
CHAPTER FOUR
The Adjustment
to
Temperature
to attain a practical system for the temperature
In order
adjustment, the general practice has been to solder together brass and steel for the rim of the balance.
The
brass occupies
the outer portion of the rim, consuming about three fifths
of the total thickness.
The rim
is
cut near the arms to permit
the turning in and out of the loose ends, thus changing the active diameter of the wheel.
for
the
changing
elasticity
This movement compensates
of the balance spring during
known as the compensating balance. A compensating balance made of brass and Invar (a nickle-and-steel alloy) when used in temperature changes. This type of balance
is
connection with a hardened steel balance spring has been and is
today the most satisfactory arrangement for combating
the temperature error.
However, there
is
a definite trend toward the use of a
plain uncut balance of a single metal
and a balance spring
of a nonrusting, nonmagnetizing alloy,
chromium, and tungsten,
made
principally of
called
Elinvar.
A
iron,
nickle,
slight
temperature error exists, but there are certain advan-
tages that
make
improvement. tories,
for
it
desirable to continue research for further
This
is
apparently the opinion of watch fac-
new models have appeared 156
lately
with definite
:
ADJUSTMENT TO TEMPERATURE
157
changes in the design of the movement as well as the balance
and spring, showing a persistent facturers to improve this
new
effort
on the part of manu-
type of balance assembly.
Watches with com-
Correcting the temperature error.
pensating balances are usually adjusted to temperature be-
tween 40 degrees Fahrenheit and 95 degrees Fahrenheit.
The
rules for the adjustment are as follows
1,
If the watch runs slow in heat,
move any even number
of screws that are opposite each other an equal distance
toward the loose ends of the rims. 2.
If the watch runs fast in heat,
move any even number
of screws that are opposite each other an equal distance
toward the balance arms. Experience
temperature adjustment
in effecting
sary before the horologist the alterations.
More
is
able to decide
is
neces-
on the extent of
often than otherwise, several trials
are required. If the screws are
moved
the poise should be examined.
Temperature adjustment
practically permanent.
many
The
balance
considerable distance
may
is
be trued and poised
times without interfering with the temperature adjust-
ment.
However,
in
changing a balance spring, readjustment
would be necessary.
Equipment used ment used erator.
for temperature adjusting.
for temperature adjusting
An
is
The
equip-
an oven and a refrig-
oven suitable for the purpose need be nothing
more than a box fitted with an electric light bulb, a rheostat, and a thermometer. The thermometer is placed inside and in such a
manner
an opening
that
in the box.
it
can be conveniently read through
An
ordinary electric refrigerator will
serve the purpose for the lower temperature.
A PRACTICAL COURSE IN HOROLOGY
158
Problems 1.
Does the
fitting
of a
new balance
spring alter the temperature
adjustment of a watch? 2.
slow 3.
A
watch that
in heat.
Name
is
equipped with a compensating balance runs
How do you
correct the error
?
the advantages of a solid, single-metal balance and
Elinvar balance spring.
Part III
CHAPTER FIVE
The The
Work
Practical
of Adjusting
practical use of the instruction that has been written
these pages will presently be demonstrated by several
in
examples taken from actual practice when the writer was
engaged in practical work
The
at the bench.
data for the
watches to be adjusted are kept in a small notebook. date, customer's
name, the make,
size
The
and grade of the watch
are recorded, followed by the several rates and an account
made
of the changes
to effect a satisfactory rating.
Practical Problems in the Adjustment to Positions Preliminary notes. several
factors
The method
It will
be necessary to briefly discuss
before considering the concrete problems.
of computing the variation of the rate in the
different positions will be next in order
explanation, the reader 163. rate
The
â&#x20AC;&#x201D;that
first is,
is
referred to Adjustment 4 on page
the rate without setting the watch except at the test.
The
first
figure
seconds, the rate for 24 hours, written
Without
to assist in the
column, reading down, shows the progressive
beginning of the
up.
and
shows a
â&#x20AC;&#x201D;
2,
setting the watch, the figure
loss of
2
the rate for dial
below shows the
variation after running the watch in the position of dial
down, which
is -\-2.
The next
figure
159
below shows the varia-
A PRACTICAL COURSE IN HOROLOGY
160
tion after running in the position of pendant up, the rate
being
—
For pendant
19.
and for pendant
The
left the
progressive rate
rate for each period of
tracting the lesser figure
are
all
right the progressive rate
plus or
24 hours
from the
is
43.
computed by sub-
greater, provided the rates
minus. However,
all
—
is
—30
is
the rates are plus and
if
minus, the figures are added and the sign before the rate
added
prefixed to the 24-hour rate and entered in the
is
To make
second column.
the example, explaining
recorded as for dial
and the the
—
down
up
is
rate for pendant right
is
column as
-j-2
showing
-j-4,
The
-\-2
and
rate
— —
19,
21,
— 19
and
between
both of which are shown in the second
not necessary
positions the
—2 and
the difference between
Thus we may compute
Maximum
rate
deducted from correct time. The
the 24-hour rate without
the necessity of setting the watch for every is
The
rate for pendant left is the difference
43,
this
rate for dial up,
entered in the second column as loss
—30 and the —30 and —
The
computed by adding together
is
result
:
in excess of correct time.
showing the amount of
column.
way
computed by adding together
amount of the gain
and the
in this
with
shall continue
carried to the second column.
2, is is
it
we
this clear,
rate is entered in the second
for pendant
last
when
trial.
Of
the electric timing machine
allowance in positions.
course, is
used.
Before testing in
watch should be regulated to run within 15
seconds in 24 hours.
The
extent of variation between 5
positions in high-grade, 16-size watches should not exceed
6 seconds
in
24 hours.
For watches of a cheaper grade
and for most of the average grades of not more than 10 seconds
is
rate between the positions of dial
in the 12 size, a variation
considered passable.
The
up and pendant up are the
2 6 3
WORK OF ADJUSTING
PRACTICAL
161
most important and should receive special consideration. The rate
between these two positions should not exceed 3 or 4 ;
and
in
most cases the manipulation of the regulator
that
is
in fact,
it is
not
produce close agreement
seconds
difficult to
is
all
necessary.
In the following pages are shown several examples of 3
and
5 position adjusting.
These examples should be studied
carefully.
Adjustment 1. Watch 16 size, 23 jewels
— Repairs—
cleaned, staff fitted, balance poised.
After cleaning and repairing, the watch was tested in 3 positions
and
it
was found
to
have a variation of 15 seconds
with a gain in the pendant-up position. Dial up Dial
down
Pendant up
An
—6 — — 12 — — 3 +9
(15)
examination showed that the spring was level and
properly centered and that the regulator pins were tightly closed.
Accordingly the pins were spread slightly and after
timing by turning in a pair of timing screws, the test was again tried, this time with the following results. Dial up Dial
down
Pendant up
—2 — — — 5
—9
—
4
(2)
Adjustment 2. Watch 16 size, 7 jewels
— Repairs— Cleaned, main spring
The below.
first test
fitted
showed a variation of 28 seconds as shown
1
A PRACTICAL COURSE IN HOROLOGY
162
+8+8
Dial up
+15 Pendant up +48 Dial
The
down
+7 +33
(28)
error being considerable in the pendant-up position,
was reasoned
that the balance
was out
of poise.
it
The spring
was removed and the balance was tested for poise. A slight poise error was found, but the want of poise could not be responsible for the whole variation of 28 seconds.
There-
fore in addition to poising the balance, the regulator pins
were spread test
and after timing the watch, the next
slightly
showed a much improved Dial up Dial
down
Pendant up
+3 +3 +6 +3 +5 — 1
rate.
(4)
Adjustment 3. Watch 16 size, 17 jewels
— Repairs — cleaned, balance poised
This example showed a loss in the pendant-up position instead of a gain as found in the previous examples.
Dial up
— —
2
down 4 Pendant up —18 Dial
As
the watch
was
—2 —2 —14
(12)
in excellent condition
throughout, the
was most likely to be found in the regulator pins. An examination showed that the pins were open and the correc-
error
tion consisted of closing the pins.
shown on the second test. —1 —1 Dial up Dial
down
Pendant up
—2 — — —3 5
(2)
A
much improved
rate
is
WORK OF ADJUSTING
PRACTICAL The adjustment watch
163
running the
to five positions consists in
pendant right and pendant
in the positions of
left in
addition to dial up, dial down, and pendant up. Because you find a close rate
between the three positions
the watch will be an excellent timepiece.
present that would
show up only
five positions, for often
construction of the watch
—
no proof that
Errors could be
in the pendant-right
and
Fine watches should be adjusted to
pendant-left positions.
Adjustment 4. Watch 18 size,
is
an unsuspected error in the general is
discovered.
15 jewels
—cleaned
Repairs
The
first test
showed the following
rate.
—2
Dial up
+
4
—21 —11 —13
(25)
The balance spring was pinned
so that the fast position
stood in the direction of pendant up, yet the pendant-up rate
was
slow.
The
dial-up and dial-down rates were also too
great to be allowed to pass.
The
balance was placed in the truing calipers and the bal-
ance spring was examined and found to have an eccentric
motion
at the collet.
and the balance
vv^as
(Incidentally, the spring
tested for poise,
was removed
showing a
slight poise
error with the excess of weight on the lower side of the
balance
when
in the
pendant-up position.)
The balance was
poised and the balance spring replaced and trued.
Further
examination showed a slight vibration of the
between
sprin.sr
:
A PRACTICAL COURSE IN HOROLOGY
164
the regulator pins.
were to
Since the rates in the vertical positions
slow the pins were closed. The watch was regulated
all
mean time and
the results of the second test are
follows
Dial
up
—2 —1
—4
shown as
4
WORK OF ADJUSTING
PRACTICAL The
arc of
165
motion of the balance was examined and
found to be somewhat shorter than
it
should be.
escapement was in excellent condition, the main spring
was
such was the case.
was assumed
that
and an examination showed that
set,
A
it
Since the
new
spring was fitted and the motion
The
was considerably improved.
train
was examined and
a cracked jewel in the pallet bridge was discovered,
al-
was discernible only with a strong glass. A new jewel was fitted and without doing anything else the next test showed a much improved
though the crack was so
slight that
it
rate.
+2 +2 +3 +1
Dial up
Dial
down
Pendant up
— —
Pendant right
—1
Pendant
—7 —6
1
left
(8)
Adjustment 6. Watch 12 size, 17 jewels
— Repairs—cleaned, balance poised, balance spring trued
This example shows that
possible to have a close rate
it is
between the horizontal positions and pendant up, yet the pendant-right and pendant-left positions
may
be far from
satisfactory.
— — —4 — 3+1
Dial up Dial
down
-|-
Pendant up Pendant right Pendant
5
5
left
1
—23 —20 —98 —75
(76)
The watch showed an abnormally slow left position.
It
was observed
rate in the pendant-
that the arc of motion of the
:
A PRACTICAL COURSE IN HOROLOGY
166
balance was shorter than
showed
it
that the drop locks
the drop locks were
made
should be.
Further examination
were too deep, and, accordingly, lighter.
The escapement was
re-
banked to the drop and the necessary corrections made, yet after the balance was replaced the arc of motion was still too short.
what
The mainspring was removed and found set
and a
of watch.
little
weaker than should be used
some-
in this grade
After replacing the mainspring with one of the
proper strength, the next ing results
to be
test in position
showed the follow-
Dial up
A PRACTICAL COURSE IN HOROLOGY
168
Noting also that the dial-up position was
formed.
lower pivot was rounded the second test
After timing the watch,
slightly.
showed the following
rate.
Dial
up
Pendant right
Dial
down
Pendant
— —
left
Pendant down
Pendant up
terminals.
formed
collets
The above watch when
8
is
3
(10)
best rates
and theoretical inner
carried by the
at a rate within ten seconds a
5
given to show
The very
the natural error can be reduced.
can be attained only with poised
— —
5
—18 —10
This example with the Lossier inner curve
how
fast the
owner pef-
month.
Practical Problem in Isochronal Adjusting In the chronometer altering the
it
possible to attain isochronism
is
form of the terminal curves or by
certain relation of the pinnings between collet ever,
any attempt made
ods in watches adjustment. it
is
As
may
and
to effect isochronism
stud.
How-
seriously interfere with the position
the position adjustment
satisfied.
selecting a
by these meth-
is
more important,
desirable to sacrifice the isochronal rating
cannot be
If the spring
is
when both
pinned correctly for
position adjustment, the best pinning for isochronism
may
or the
by
may
not exist, depending on the length of the spring and
design
of
the
As stated in Chapter Three, best we can do to attain practical
watch.
Isochronal Adjusting, the
isochronism in watches
lies in
the correct formation of the
terminal curves.
Balance springs supplied by the manufacturer. fitting
When
a spring supplied by the manufacturer for a certain
model of watch the proper length need not be considered.
4
:
WORK OF ADJUSTING
PRACTICAL
for that factor has already been taken care of
169
by the maker.
There are occasions, however, when the spring in the watch has been considerably shortened by some workman who was not acquainted with the laws of isochronism as governed by
In such cases the spring must be
the length of the spring.
replaced with a
isochronism
is
set,
rate
is
of the proper length,
if practical
to be expected.
Method used and
new one
in testing isochronism. After being
the watch
is
wound
run for 6 hours, after which time the
The watch is then run for 24 hours from was wound and set, when rate is again recorded.
recorded.
the time
it
The watch
run 6 hours longer without winding and the
is
recorded for the third time.
rate
is
and
last
period of 6 hours
The
rate for the first
separately computed for a
is
period of 24 hours. In this manner the variation of the rate
is
shown for the long and short arcs.
A practical problem. adjusting
it is
been stated.
In showing an example of isochronal
possible only to prove that
The following example,
which has already
therefore,
shows how
the correction of the eccentric motion of the balance spring
improves the isochronism. The spring had an eccentric motion in the direction opposite the regulator pins
showed the following
P.M. 8:00 P.M.
set
Rate in 24 hours '2 :00 P.M. next day Short arcs
The
first test
first test
results
[2 :00
Long arcs
and the
8 :00 P.M. Rate in 24 hours
showed a
—1
—
—3 —7 —16
(12)
loss of 12 seconds in the short arcs.
:
A PRACTICAL COURSE IN HOROLOGY
170
After correcting the overcoil so that the vibrations of the spring were concentric to the center of the balance, the next test
showed a much improved
rate
A.M. 3:00 P.M.
'9 :(X)
Long arcs
set
Rate in 24 hours '9 :00
Short arcs
Practical
Of is
all
A.M. next day
+1^
P.M. Rate in 24 hours 3 :00
Problem
in
+1
â&#x20AC;&#x201D;2
(2)
Temperature Adjusting
the adjustments of watches temperature adjustment
the best understood, no doubt because of the fact that
it
has been the principal error to be eradicated in the chronometer
and therefore studied more than the
One example correction in
all
other.
of temperature adjusting will suffice, as the cases consists merely of
pairs of balance screws
from one position
The example shown below had
moving opposite
to another.
a rate of 20 seconds fast in
heat:
Coldâ&#x20AC;&#x201D; 5 To show The
+15
the location of the screws and the position to
which they are moved, holes.
Heat
it
is
holes nearest the
the next 3,
etc.,
the highest
customary to number the screw
arms are numbered
number
1,
the next 2,
indicating the last holes
near the loose ends of the rims. Since this example showed a gain in heat, the correction consisted of
moving the screws
toward the balance arm.
number 9 were moved
at the free ends of the rims
Accordingly, the screws in holes
to holes
number
5,
and the screws
in
WORK OF ADJUSTING
PRACTICAL
171
number 11 were moved to holes number 9. The next showed a variation of 10 seconds slow in heat.
holes test
Cold
+10
Heat
This shows that the correction was overdone. Therefore the screws in holes
The next
test as
number 9 were moved
to holes
number
11.
recorded below shows a very satisfactory
rate.
+6
Cold
Heat
+5
Final Timing and Regulating
Timing screws and washers.
After a watch has been
cleaned and repaired, the variation in time should not be corrected by moving the regulator, but rather by turning in
or out the timing screws as the watch
may
require.
Some
watches do not have timing screws and the correction must necessarily
consist in
adding timing washers. in
undercutting the balance screws or
H the watch runs within
30 seconds
24 hours the regulator may be used.
The middle temperature
error.
It
was
stated in Chapter
Four of Part I that the middle temperature error causes a variation of from 2 to 6 seconds, being faster than the rates between the extremes of heat and to regulate the watches
cold.
It is better,
therefore,
on the rack to run a few seconds
fast
rather than just on time, for the watches on the rack are
running
in the
ture errort
is
normal temperature and the middle temperain
effect.
When
carried in the pocket the
higher temperature would cause the watch to run slow.
When
Delivering the watch.
customer
tell
him
that
it
is
delivering a watch to the
preferable to wind the watch in
A PRACTICAL COURSE IN HOROLOGY
172
There
the morning.
is
a good reason for so doing. The best
part of the mainspring is used during the day
watch
is carried.
in
a vertical position,
to take advantage of the extra
by winding flat
on a
in the
power
morning. Because a watch
table or dresser at night
it is
practice of winding the
watch
is
it
is
better
would be avalable
that
is
usually laid
at once evident that a
more nearly uniform balance arc takes place
The
the
Since the balance has a sHghtly shorter arc
when running
of motion
when
adhered
if
the above
to.
horologist should take time to explain to the customer
that there will probably be a variation of several seconds
during the
first
party to come correct time
few weeks of carrying the watch and ask the
in, in
a week or two, for comparison with the
and for further regulation
the customer that
it
a watch and that he
if
necessary.
Tell
takes several weeks to properly regulate
may come in as often as he finds it convenient. In this manner much of the dissatisfaction of the repair department is eliminated besides making many friends for the store.
GLOSSARY OF TERMS Addendum.
The
beyond the pitch
portion of a tooth of a wheel or pinion circle.
Arbor. Axis of the balance wheel or mainspring
The
Balance.
barrel.
vibrating wheel of a watch, which, in con-
junction with the balance spring, regulates the progress of the hands.
Balance
arc.
A part of the vibration of a balance.
Balance cock. The support for the upper pivot of the ance
bal-
staff.
A
Balance spring.
long fine spring that regulates the vibra-
tion of the balance.
Balance
staff.
Banking
pins.
The
axis of the balance.
Two
pins that limit the angular motion of
the lever.
Banking
to the drop.
An
adjustment of the banking pins
permitting the escape wheel teeth to drop off the pallets.
Barrel.
A
circular
box for the reception of the mainspring.
Barrel arbor. The axis of the barrel, round which the mainspring
Beat.
coils.
One
Beryllium
vibration of the balance alloy.
An
alloy
and
spriiig.
of iron, nickel, and a small
percentage of beryllium, used for balance and balance spring. 173
A PRACTICAL COURSE IN HOROLOGY
174
A
Breguet spring. raised above
is
and carried over the body of the spring.
Upper
Bridge.
balance spring in which the outer coil
plates in a
watch for the support of the
wheels.
Two
Butting.
when
wheels touching on the points of the teeth
entering into action with each other.
Cannon
The pinion with a long
pinion.
minute hand
is
fixed.
Center of gravity. That point
mass
is
pipe to which the
in a
body around which the
evenly balanced.
Center wheel.
The wheel
in a
watch the axis of which
usually carries the minute hand.
Chronograph.
A
watch that has a center-seconds hand
driven from the fourth wheel which can be started, stopped,
and caused to
fly
back to zero by pressing on a knob or
lever.
Chronometer.
A
boxed timepiece for use on ships
Chronometer escapement. in chronometers. Invented
Circular escapement. the central portion
An
at sea.
A spring detent escapement used by Pierre LeRoy about 1765. escapement so constructed that
of each pallet stone's impulse
face
stands at an equal distance from the pallet center.
many
spaces
That type of wheel which has a
lifting
Circular pitch. The pitch circle divided into as as there are teeth on the wheel or pinion.
Club-tooth wheel.
face off the end of the teeth.
Clutch pinion. stem.
The
pinion surrounding the square of the
Serves alternately to wind and set the watch.
GLOSSARY OF TERMS
A
Collet.
175
small, circular piece fitting friction-tight to the
balance staff and which
is
pierced to receive the inner coil
of the balance spring.
Compensating balance. A balance the rim of which is made of brass and steel. The diameter is caused to increase or decrease in different temperatures, so as to compensate for
changes in temperature on both balance and spring.
Corner safety
A
test.
of safety lock
when
test to
show the presence or absence
the slot corner
is
brought in contact
with the roller jewel.
A
Crescent.
circular notch in the edge of the roller table
for the reception of the guard pin or finger.
A
Crown.
grooved circular piece fastened to the stem for
winding the watch.
Crown Curb
A wheel that drives the ratchet wheel.
wheel.
pins. Regulator pins.
Curve
A
test.
used to discover
test
if
the curves of the
lever horns are correctly related to the roller jewel.
Cylinder escapement.
Thomas Tompion
Dedendum.
The
A
frictional
escapement patented by
1695.
portion of the tooth of either wheel or
pinion inside of the pitch circle.
trol
A
two wheels and two pinions that conthe progress of the minute hand and the hour hand.
Dial train.
train of
Diametrical pitch. into as
many
Discharging wheel tooth
The diameter
of the pitch circle divided
spaces as there are teeth on a wheel or pinion.
pallet. slides
the pallet stones.
The
pallet
stone which
an escape-
over in order to emerge from between
A PRACTICAL COURSE IN HOROLOGY
176
The
Distance of centers.
distance on a straight line
from
center to center, as between balance center and pallet center.
A
Double-roller escapement.
which a separate
A
Draw.
roller is
form of
lever escapement in
used for the safety action.
force that keeps the lever against the banking pins,
created by the slant of the pallet stones.
Driven. The mobile that Driver.
The mobile
is
being forced along by the driver.
that forces the other along.
Drop. The free motion of the escape wheel after impulse
to
the pallets has been given.
Drop
lock.
The
extent of the lock on the pallets after an
escapement has been banked to the drop.
A
Duplex escapement.
watch escapement
escape wheel has two sets of teeth.
by pressing on the balance pulse to the balance.
staff.
The balance
A
which the
One set locks The other set
the wheel gives im-
receives impulse at every
other vibration. Accredited to Pierre
Epicycloid.
in
LeRoy about
1750.
curve generated by a point in the circum-
ference of a circle as
it
rolls
upon another
circle.
It
forms
the kind of tooth used in watch wheels.
Equidistant escapement.
An
escapement so constructed
that the locking faces of the pallet stones stand at
distance
Elinvar.
from the
A
iron, nickel,
for balance
an equal
pallet center.
nonrusting,
nonmagnetizing alloy containing
chromium, tungsten,
silicon
and balance spring.
Fork. The horns and
slot
of the lever.
and carbon. Used
GLOSSARY OF TERMS Fourth wheel. The wheel of a watch
177
that drives the escape
pinion.
Guard pin or
A pin or finger
finger.
working
in
and out of
the crescent to preserve the safety action.
Guard safety
test.
of safety lock
A
when
test to
show
the presence or absence
the guard pin or finger
is
brought in
contact with the edge of roller.
Heel
Letting-oif corner of a tooth of the escape
of tooth.
wheel.
Horns. The
circular sides of the fork leading into the slot.
Hour wheel. The wheel
A
H3rpocycloid.
Used
when
it is
rolled within another circle.
pin. Roller jewel.
A
Invar.
hour hand.
curve generated by a point in the circum-
ference of a circle
Impulse
that carries the
steel
in the
alloy containing about
36 per cent
nickel.
making of balance wheels.
Isochronism. The property of a balance spring that allows it
to
perform the long and short arcs
Letting-off comer. tooth lets
Lever.
A
Corner of a
in equal time.
pallet stone
from which a
off.
metal piece attached to the pallets that carries
impulse to the balance.
Lever escapement.
A
watch escapement that delivers im-
pulse to the balance by lever.
The extremity
acts directly
on a
means of two
The
and a
of the lever has a forked slot that
roller jewel
balance. Invented about 1750 by Lift.
pallet stones
which
is
attached to the
Thomas Mudge.
pitch or slant of a tooth or pallet stone.
A PRACTICAL COURSE IN HOROLOGY
178
Line of centers.
A
line
drawn from center
to center, as of
any wheel or pinion. Locking. The overlapping of a tooth on a
The
Lossier curves.
pallet stone.
and inner terminals
theoretical outer
as designed by L, Lossier.
Main
The toothed wheels
train.
in a
watch that connect the
barrel with the escapement.
Middle-temperature error. The temperature error between the extremes of heat and cold characteristic of a com-
pensating balance and
Minute
Out
steel
The wheel
v^^heel.
balance spring.
driven by the cannon pinion.
of angle. Unequal angular motion of the lever from the
line of centers
A
Overbanked.
ment
when an escapement
The
Overcoil.
to the drop.
term used to indicate that the lever escape-
last coil of the
up and over the body of the
The metal body
The term Pallet staff.
Breguet spring that
Pallet stones.
contains the pallet stones.
arms and
pallet stones.
axis of the pallets.
Jewels or stones inserted in the pallet arms.
spring.
formed on
bent
attached to or a part of the lever.
includes the pallet
The
is
spring.
The metal body which
Pallet arms.
Phillips*
banked
out of action.
is
Pallets.
is
lines
A
balance spring with terminal curves
laid
down by M.
Phillips.
The term
"Phillips' curve" is rarely used.
Pinion. The smaller wheel with teeth called leaves, working in connection with a larger wheel.
GLOSSARY OF TERMS Pitch
A
circle.
circle concentric
a toothed wheel and cutting
from
179
with the circumference of teeth at such a distance
its
their points as to touch the corresponding circle of
a pinion working with
common
and having with that
it
circle
a
velocity, as in a rolling contact.
Pitch diameter. The diameter of the pitch
circle.
Pivot.
The end
Plate.
Discs of brass or nickel which form the foundation
of a rotating arbor.
The lower
of a movement.
plate lies next to the dial.
The
upper pieces supporting one, two, or three wheels are In the full-plate watch
generally referred to as bridges.
the upper piece
A
Potence.
called the top plate.
is
hang-down bracket used for supporting the
lower pivot of the balance
staff in full-plate
Quarter screws. Four screws used Ratchet wheel.
A wheel that is
in timing.
fastened to the barrel arbor.
The name given
Ratchet tooth wheel.
watches.
to the English type
escape wheel which has pointed teeth.
Receiving
The
pallet.
pallet stone
over which a tooth of
the escape wheel slides in order to enter between the pallet stones.
Remaining
lock.
The
lock remaining
More
corner tests are tried.
Repeater.
A
two gongs. anism
watch that
A
lever
into action.
A
Is
the guard and
often called "safety lock."
strikes,
having two hammers and
provided to set the striking mech-
quarter repeater strikes the hour and
the last quarter hour. strikes the
when
A
minute repeater,
number of minutes
in addition,
since the last quarter.
;
A PRACTICAL COURSE IN HOROLOGY
180
An
Right-angled escapement.
escapement in which the Hne
of centers of the escape wheel and pallets are at right angles
and balance.
to pallets
A
Roller jewel.
long, thin jewel inserted in the roller table
sometimes called impulse
A
Roller table. in
Run
which
pins
circular disc attached to the balance staff
is fitted
of lever.
when
pin.
the roller jewel.
The motion
of the lever toward the banking
Run
slide is present.
always equals
slide.
Safety lock. The lock remaining when the guard and corner tests are tried.
Semitangental escapement.
An
ing face of the receiving pallet
escapement where the lockis
planted 31 degrees from
the line of centers and the discharging pallet 29 degrees
from the
line of centers.
The
receiving pallet locks only on
the tangent.
The space
Shake. pallet
from the
separating the letting-off
heel of a tooth
when
locked at the lowest locking corner.
comer of
the
the opposite pallet
Shake
is
always
is
less
than drop.
Single roller escapement. roller
and safety
actions.
The opening
form of
lever escapement in
performs the functions of both impulse
which one
Slide.
A
of the banking pins beyond that of drop
lock.
Steady pins.
two
Pins used to secure the perfect alignment of
pieces of metal.
Stem. The winding arbor of a watch.
GLOSSARY OF TERMS
A
Stop work.
181
mechanical device for preventing the over-
winding of a mainspring. Straight line escapement.
An
escapement in which the
centers of the escape wheel, pallets,
and balance are planted
in a straight line.
Stud.
A small piece of metal pierced to receive the outer coil
of the balance spring.
Third wheel. The wheel of a watch
that drives the fourth
pinion.
Timing screws.
Screws used to bring a watch to time,
sometimes called the mean-time screws.
Toe
of tooth. Locking corner of a tooth of the escape wheel.
Total lock. Drop lock with Train.
A
slide
added.
combination of two or more wheels and pinions,
geared together and transmitting power from one part of a mechanism to another.
Tripping.
A
tooth of the escape wheel running past the
locking face of a pallet stone at a time
when
safety lock
should be present.
Wheel. Any
circular piece of metal on the periphery of
which teeth may be cut of various forms and numbers.
Winding
pinions.
drives the
A
pinion surrounding the stem that
crown wheel.
WATCHES Borer and Bowman,
Modern Watch Repairing and Adjusting DeCarle, Donald,
With
the
Garrard, F.
Watchmaker at
the
Bench
J.,
Watch Repairing, Cleaning and
Adjtesting
Gribi, Theo.,
Practical Course in Adjusting
Grossman, Jules and Herman, Lessons in Horology
Hood, Grant,
Modern Methods in Horology Kleinlein,
Walter J.,
Rules and Practice in Adjusting Watches Practical Balance and Hairspring Thisell,
Work
A. G.,
Watch Repairing Simplified Wilkinson, T.
J.,
The Escapement
a7id Train of 182
American Watches
BIBLIOGRAPHY
WATCHES AND CLOCKS Britten, F.
J.,
Watch and Clock Makers* Handbook Haswell, Eric,
Horology Saunier, Claudius,
Modem Horology
Treatise on
CLOCKS Garrard, F.
J.,
Clock Making and Repairing
Gordon, G. F.
C.,
Clock Making, Past and Present
Langman and Electrical
Ball,
Horology
Philpott, Stuart F.,
Modern
Electric Clocks
Robinson, T. R.,
Modern
Clocks, Their Repair
and Adjustment
HISTORY Britten, F.
J.,
Old Watches and Clocks and Their Makers Chamberlin, Paul M.,
If s About Time Gould, Rupert T.,
The Marine Chronometer,
Its
History and Developinent
183
184
A PRACTICAL COURSE IN HOROLOGY
Hering, D. W.,
The Lure of
the Clock
Nutting, Wallace,
The Clock Book
ALLIED SUBJECTS Bennett, Charles A.,
Beginning Problems in Mechanical Drawing
Eaton and Free,
Machine Shop Science and Mathematics Feirer and Williams,
Basic Electricity
McMackin and
Shaver,
Mathematics of the Shop Roberts, William E.,
Beginning Mechanical Drawing
INDEX
A
B PAGE
Action fork and roller
47, 110
47
four-to-one roller
of
flat
152
spring
47
three-to-one roller
45, 110
safety in
unlocking and impulse. pallet
47
44, 100
on wheel
wheel and pallet_44, 100, 106
Addenda
33
Adjusting
escapement
Balance
14, 52-53
84
axis
counterpoising
145
motion
132
pivots
129
poise of
134, 136
Balance spring action of
and
its
flat
poise error
128-172
Breguet type
100-113
eccentric motion of
isochronism
fitting of
128, 150-155, 168, 169
position practical
PAGE
work
14, 53,
58
152
140
144
97 88,
89 58
flat
128, 140-149
isochronal condition of _ 150
159
length of, on ischronism 151
of
regulator pins
146, 147
temperature
on position error truing of
128, 156-158, 170
Altering drop locks
102
73-84
Banking pins
41-101
to drop
Barrel
102,119,120,121
97
staff
Balance
Banking
Angle, escapement, out of
144
101
14,24
Angular motion of lever_ liO
Beat
14
Arc of motion
Bell-metal laps
7S
of balance. 133 185
A PRACTICAL COURSE IN HOROLOGY
186
PAGE Bezel-type jeweling
Boxwood
68,
laps
PAGE
70
Circular pitch
79
Cleaning watches
Breguet balance spring
33,
Burnisher
69
Butting
63
Butting error, example of 121
104
Close outside
104, 120
Club-tooth escapement 45, 107, 108
Qub-tooth escape wheeL Collet
c new
23
train
beats
18,88
length of mainspring
26
length of overcoil
91
number of hours watch will
teeth
run
24
and leaves of miss-
ing mobiles
fast trains- 19,
53
Cone
80
pivot
Controlling mechanism _52-60
Converting
flat
spring into
Breguet
94,95
Corner freedom
117, 120
Comer
110, 112
safety test
Counterpoising
20-22, 30
41,
Curve
turns of pinion
15
Dedenda, dedendum
Cast-iron laps
78
Cement chucks Center of gravity
82, 85
59-141
Center wheel and pinion.
16
33, 34, 175
D Degrees of angular motion
1
Degrees of
110
lift
Delivering the watch
10
171
Demagnetizing a watch__ 138
Centers distance of
32
Depthing too deep
line of
33
Depthing
42
Depthing too shallow
Circular pallets
50
113
test
16-18
28
145
Crescent
25
Cannon pinion
20
Compensating balance
thickness of mainspring
turns of train
39
77, 80, 84, 143
Comments on
Calculating a
124-126
Close inside
58,90,144,152
37
62,
64 35
tool
62,
64
INDEX
187
PAGE Dial train
Diameter,
15,
28-31 32,
full
pitch
Diametrical pitch
32
Escapement
33
adjusting
roller
45, 103,
Drawing
lever escapement
83 14, 39-51,
100-123
114
43
50
single-roller
49
104 1
drawing
semitangental
14
Driver
33 46, 104
tests
116
theoretically correct
114
Escape wheel
number of
16,
weight of
131
101
close outside
120
F
101, 102
Fast pendant-up
deep
118,119,121
light
119
161
Fast trains
19
Final timing and regulat-
ing
E ance spring of
171
Finishing end of balance
Eccentric motion of bal-
Effect
39 43
teeth of
banking to the
lock
50
32
33
Drop
100-123
44
Driven
Drop
staff
lever
14,40
41,
Draw
in
double-roller
Distance of centers
Double
common
making
161-164
Discharging pallet
Errors
36
Dimensioning, three and five position
PAGE
97
manipulating
regulator pins
Elinvar
57,
83
pivots
Fitting balance springs
88-99
Five positions, adjustment
146
to
156
Flat spring
163
Epicycloid
33
on isochronism
152
Equidistant pallets
41
on position error
144
Flat springs, fitting
89
Equipment
for
tempera-
ture ad j usting
157
Fork and
roller action
47-1 10
A PRACTICAL COURSE IN HOROLOGY
188
PAGE
PAGE
Fork
40,
slot
47
Hub, turning and rough-
Four-to-one roller action.
47
ing
81
Fourth wheel and pinion_
16
Hypocycloid
34
Friction jeweling
70, 71
I
Impulse
G
130
Impulse and unlocking ac32-38, 62
Gearing Gravers for setting jewels
68,
69
for turning staff
73,
74
Grinding
and
polishing
79
Grinding materials
Guard freedom 117
none
119 121
110
117-119
40
Influence of
the
escape-
ment on the adjust130
Invar
57,
Heel of tooth
168 154
Isochronal error
Isochronism 150-155
adjustment to
length of balance spring
on
of cleaning
watches
156
Isochronal adjustment,
151
169
testing to
H Hand method
Impulse face
example of
excessive
Guard pin jams Guard safety test Guard tripping error
47
ments 80
cone pivot
tion
J 124
Jeweling
:
68-72
40
Jewel pin or roller jeweL40, 41
148
L
Horizontal positions, ad-
justment to
Horns of fork
40
Laps
Hours of running
24
Length of balance spring- 151
Hour wheel
28
Letting-ofÂĽ corner
78,79
40
INDEX
189
PAGE 40
Lever
Middle-temperature error
110
angular motion of
escapement
39-51,114,116,130
45,105,107,110
Lift
PAGE
33
Line of centers
54, 171
Minute pinion
28
Minute wheel
28
Motion of balance
133
Motion of balance spring.
97
Lock drop safety,
N
tests
14,101,110-113 114
total
Locking
44
Locking face
40
Natural error
Narrow roller jewel Number of teeth of escape
59, 60, 91,
43
Machine method of cleaning watches
Magnetized
15,
129
120
space in barrel
58,93,94
Overcoil
P
allowance
and
Pallet
and wheel action
45
tooth, width of
44
27
Pallet impulse face
40
25
Pallet letting-off corner
40
24, 132
Pallet locking face
40
in
Pallets
26,
Mainsprings
Pallet
Pallet fork
thickness of
160
positions
for
102-120
of angle
26
length of
staff
Outside drop, close
137
Mainspring
Measuring
124
138
tools
train
Maximum
Oiling watches
Out 125
Magnetism
Main
o
95
M
49
wheel
Lossier inner and outer terminals
142, 144
balance
adjusting of circular
75
discharging
40,41, 131
14,40, 131
100 42,
46 40
A PRACTICAL COURSE IN HOROLOGY
190
PAGE equidistant lift
41,
on
46
105
40
receiving
45, 110
safety action
semitangental Pallet stone
work of
ing
159
Principles of gearing
Problems
33
in adjusting
117
40
isochronism
168
position
161
temperature
170
62,
64
depthing too shallow
62,
64
R
28
too large
62,
63
too small
62,
64
13,32,62,65,85
Ratchet tooth escape
wheel
39
Receiving pallet
40
Regulating and timing
Pinning of balance spring 143
at the collet
adjust-
escapement
depthing too deep
Pinions
Practical
42
Pinion
minute
PAGE
Regulator
pins,
171
adjust-
ment of
Pitch circle
32
Remaining lock
37
Resistance to unlocking
circular
33,
diameter
32, 35
33
diametrical
146 111
19, 42,
Roller, single
103
and double
77
41,49,50
Pivoting
85-87
Roller and fork action_47, 100
Pivot polisher
77,
Pivot, conical, turning a
Pivots,
79
making and turn-
Poise error, analysis of
40,41,49
Roller jewel
74,77
ing
82,83
Roller axis
135
Poise of the balance
134-136
Polishing cone pivot
80
Position adjusting 140-150, 159
40
Roller table
Rounding-up
tool
66
s Safety lock tests
110
Screws, timing
171
INDEX
191
PAGE (^
Setting jewels Setting
staff
cement
in
82
chuck
42, 110
Semitangental pallets
Shake
105, 120
117
Short fork
102,113
Slide
40
Slot, fork
PAGE droplock
101
lift
105
safety locks
110
shake
105
Theoretically
correct
es-
capement
114
59
Theoretical terminals
Theory of demagnetiza-
Springs
137
tion
balance
52,
88-99
Breguet, fitting
90
flat, fitting
89
Staff, balance
Third wheel and pinion
Three
positions,
ment
16
adjust-
161
to
7?>
Three-to-one roller action Staff, in
cement chuck
Staff making,
common
82
83
measuring for
Staff,
turning
Timing and regulating
171
Timing screws
171
Timing washers
171
er-
rors in Staff,
75
Toe
39
of tooth
76, 83
35-46
Tooth, width of Staking tool
65
Steel, preparation of
76
Torsion
152, 154
Train
T
dial
Teeth in escape wheel
43
156-158,170
Temperature error
_ 52-54,
Terminals, theoretical
157
59
draw
104
drop
104
15,
28-31
19 15,
129
problems
62-67
repairing
65
slow
18
wheel
Testing escapement
13
fast
main
Temperature, adjustment to
47
wheel, stretching
Tripping error
129 6 117-119
192
A PRACTICAL COURSE IN HOROLOGY
^ Unlocking and impulse
PAGE
PAGE Watch-cleaning machine
47
tions
Wheel and
44,100 42
alysis of
146
adjusting
Wheel and pinion prob-
Vibrating a balance spring
89
Vibrations
88
89,90
Wheel reducing
66
stretching
65
Wheels and pinions
Wheel work Width
w Washers, timing
62
lems
of regulator pins in
Vibrator
125
pallet action
Unlocking resistance, an-
Use
_
ac-
171
of crescent
13 13-31
50
Width of
pallet
45
Width of
tooth
35,46