Troubleshooting Application problems with new taps
Thread produced is too large
Possible causes
Solution
incorrect tap, tap geometry not suitable
apply correct tap for the material
tapping size hole too small
observe tapping size hole table in the
alignment error of tapping
- check for correct tool clamping
machine spindle axially restricted
- use mechanical feed
cold welding at the flank
- apply new tap
lead of tap unsatisfactory due
- tap with forced feed
cutting speed too high
- reduce cutting speed
lubrication or coolant supply
ensure sufficient and suitable
tolerance specification on tap does
apply correct tap for required
spiral-fluted taps,
with spiral-fluted taps only light pressure
initial tapping pressure too
taps with spiral point or left hand spiral
tolerance specification on tap does not
apply correct tap for required
incorrect tap
apply correct tap for the material to be
tap does not cut accurately
avoid strong axial forces during the
machine spindle is axially too rigid
apply tension/compression chuck
for the application
size hole or position
of the tap
to insufficient thread depth
insufficient
not correspond to specifications on drawing and/or thread gauge
Thread axially miscut
corresponding to our design, are applied with too much pressure for initial tapping
low for taps with spiral point corresponding to our form “B”
Thread produced is too small
correspond to specifications on drawing and/or thread gauge
(thread plug gauge)
to be machined
technical section. Note different tapping size hole diameters for fluteless taps.
- apply floating tap holder - check core drill
- apply tension/compression tap chuck
- apply coated tap - optimise lubrication
- apply tap with modified lead
- improve lubrication
coolant supply and check concentration
tolerances
required for initial tapping. The tap should immediately be applied within the tension/compression range
require higher axial pressure. Ensure tap operates within the tension/ compression range
tolerance
Threading tools
Problem
machined
cutting process
1641
Troubleshooting Application problems with new taps Problem Thread surface not according to requirements
Possible causes
Solution
cutting edge geometry not suitable for
apply “correct” tap for the material
cutting speed too high
- reduce cutting speed
insufficient coolant
ensure suitable coolant and sufficient
chip congestion
apply suitable tap type
tapping size hole too small
observe tapping size hole diameter specifications
with tough, hard materials loading on tool
apply hand tap sets
built-up edge
apply coated tap
cold welding
improve coolant supply
surface hardening of tappinge size hole
- check drill (cutting edge) for wear
reasons listed under: “thread surface
reasons listed under: thread surface
chip congestion
apply correct tap
tapping size hole too small
observe tapping size hole dia. acc.
teeth of chamfer lead overloaded
- longer chamfer lead (blind or
tap hits bottom of tapping
- check hole depth
- lack of or incorrect
- correct chamfer angle of
- tool hardness not suitable
apply suitable tap for the individual
the application
(concentration and supply)
too much or pitch too steep
Tool life insufficient
not according to requirements“
Tool breakage during advance or return
size hole
chamfer of tapping size hole - postional or angle error of tapping size hole
Threading tools
for the application - cutting edge geometry not suitable for the application
1642
to be machined
- optimise lubrication
volume
to DIN 336 or respective standards. Observe table for fluteless taps
- heat or surface treatment following thread production
“not according to requirements“
to DIN 336 or respective standards
through hole) - increase no. of teeth of chamfer lead by increasing no. of flutes - apply tap sets
- apply tension/compression tap chuck
tapping size hole - ensure correct tool clamping - apply floating tap holder - check core drill
application
Troubleshooting Errors and difficulties with reground taps Possible causes
Solution
Thread produced is too large
burrs
remove burrs
cutting edge geometry
- observe technical specifications
Thread produced is too small
worn section has not been
- regrind again or apply new tool.
tap too small due to no. of
- max. regrinding limit reached.
burrs
remove burrs
cutting edge geometry
- observe technical specifications
peak-to-valley height of the
- regrind again or apply new tool.
cold welding at the flanks
remove cold welding marks
cutting edge geometry
- regrind again or apply new tool.
loss of tap hardness due to heat
- check quality of grinding wheel
loss of coating
- recoat
(chamfer lead, rake-, chamfer-, spiral point angle) not retained
reground correctly
regrinds
Thread produced not according to requirements
(chamfer lead, rake-, chamfer-, spiral point angle) not retained
reground tap too large
Tool life insufficient
(chamfer lead, rake-, chamfer-, spiral point angle) not retained
development during the regrinding process
when regrinding. - observe regrinding instruction
- observe max. regrinding limits.
- apply new tap
when regrinding. - observe regrinding instruction
- observe max. regrinding limits.
- observe max. regrinding limits.
- check coolant supply
- check coating of the material to be machined
Threading tools
Problem
1643
Troubleshooting Application problems with new fluteless taps Problem
Possible causes
Solution
Insufficient tool clamping
Apply synchro chuck
Fluteless tap with short cutting portion
Apply fluteless tap with long cutting portion
Thread produced is too small
Tapping size hole diameter too large
Select correct tapping size hole diameter according to table
Thread overformed
Tapping size hole diameter too small
Select correct tapping size hole diameter according to table
Thread surface not according to requirements
Cold welding on the tool
Increase oil content in lubricant or apply neat oil
Lubricant with too little oil content
Increase oil content in lubricant or apply neat oil
Tool life insufficient
Lubricant with too little oil content
Increase oil content in lubricant or apply neat oil
Tapping size hole diameter too small
Select correct tapping size hole diameter according to table
Cutting speed too high
Adjust cutting speed
Lubricant soiled
Check filtration
Thread produced is too large
Threading tools
1648
Troubleshooting Application problems with new fluteless taps
Tool breakage
Possible causes
Solution
Lubricant with too little oil content
Increase oil content in lubricant or apply neat oil
Tapping size hole diameter too small
Select correct tapping size hole diameter according to table
Incorrect tool clamping
Check tool clamping
Threading tools
Problem
1649
Troubleshooting Application problems with new thread milling cutters Possible causes
Solution
Thread produced is too large or too small
Incorrect radius in CNC program and therefore milling of incorrect circle
Correct milling radius until thread is dimensionally correct
Thread not cylindrical
Feed rate too high
Reduce feed rate
Synchronous milling path with long threads
Modify milling direction to opposite direction
Thread surface not according to requirements, chatter marks
Cutting speed too high
Adjust cutting speed
Insufficient tool or workpiece clamping
Check tool and workpiece clamping
Tool breakage
CNC program error
Check CNC program
Cutting rates too high
Adjust cutting rates
Cutting rates too high
Adjust cutting rates
Tool applied uncoated
Apply coated tool
Insufficient lubrication and chip evacuation
Improve lubrication, coolant delivery via the spindle
Chip problems when drilling
Apply tool with IC
Feed rates too high when drilling
Incorporate pecking cycles
Tool life insufficient
Tool breakage with drill/ milling cutter
Threading tools
Problem
1661
Troubleshooting Application problems with new dies Possible causes
Solution
Incorrect clamping of die in die holder
Check clamping of die
Incorrect tolerance selected
Apply die with correct tolerance
Chips jamming
Apply dies with spiral entry
Thread overloaded due to excessive cutting rates
Increase chamfer lead
Surface in die too rough
Apply lapped die
Lubrication not optimal
Improve lubrication
Cold welding in the flanks
Check and clean flanks of thread
Tool life insufficient
Die not suitable for application
Apply HSS-E die
Thread miscut
Die jams
Thread produced is too large or too small
Thread breakage
Thread surface not according to requirements
Apply coated tool
Apply split die
Threading tools
Problem
1663