The Shrinka$e of Lumber

The volume of wood is greatest when the cell walls are saturated with water. This point is usually somewhere near 30 per cent rnoisture cohtent. The filling of the cell cavities does not increase the volume. The point at which the cell walls are completely saturated and the cell cavities are still empty is called the fiber saturation point.

As soon as the moisture is taken from the cell walls the cell starts to shrink. This shrinkage is proportional to the amount of water removed. Wood shrinks differently in various directions-greater tangentially (with the rings- and least in a lengthwise direction. The tangential shrinkage (like the shrinkage of a flat grained board) is between one and one-half to two times as much as the radial shrinkage in yigth of a vertical grained piece.) The shrinkage tangentially for our western softwoods varies from about five to eight per cent, and the radial shrinkage varies from two and one-half per cent to five per cent. The shrinkage in length is only about one-tenth to one-third of one pir cent, so it may be considered negligible.

This variation in shrinkage plays an important part in the final shape of a given piece of wbod. For example a piece of strictly vertical grained 4 x 4 of. Douglas fir will sfirink about TJ|O of. an inch in the vertical grain direction and about V10 of ah inch in the flat graindd direction. Thus, the final shape is no longer a squari but a rectangle. Again, tf_we take a.square piece which has a grain at in angle of 45 degrees, the resulting dry piece will n-o longer be a Jquare but a diamond which witt -nive its shorter d"iagonal ii the direction of the annual_ rings, due to the greatlr shrinkage of the wood tangentially. -Aiso, if we haie a board whiih is. partly flat gr-ain in the center and. vertical grain on the edge, it, when dry, will cup. The edges will iirp up when

Coast Counties Lumbermen Meet

The third meeting of the Coast Counties Lumbermen's Association was held at the Hotel San Carlos, Montcrey, on the evening of June 12. Monterey, pacific Grove arid Carmel dealers were hosts, J. O. Handley acting as chairman of the arrangements committee.

Dinner was served at 7 p.m., and R. p. Davison was chairman of the evening.

Elmer Ellis, Ellis Bros. Lumber Co., Palo Alto, addressed the m_eeting.on the.subject of the great progress made by the State Association.

A. C. Horner, Western Manager of the National Lumbcr Manufacturers' Association, talked on the Trade Extension Program of the association and also discussed the trade and grade-marking program.

Jim Farley, The Pacific Lumber Company, San Francisco, showed a motion picture film depictirig the manufacture of Redwood from the tree to the car, living at the same time an interesting talk on this subject.

The office of M. D. Bishop, secretary-manager of the association is located at 1038 Main Street, Watsonville.

the board is placed with its heart side down. This is also due to the greater shrinkage of the few tangential rings in the center of the piece. The effect of the shrinkage of the vertical grained part was only io make the piece thinner. Warping of this kind is permanent as long as the piece is kept dry.

Now let us take a piece of wdod which has the pith enclosed (boxed heart.) H'ere the greater tangential=shrinkage of the rings cannot be very well accommodated by a change in shape. The lesser shrinkage in a radial direction opposes the greater tangential shrinkage and strains are set up. The result is inevitable. The piece is going to split radially-it '1checks." This checking cannot be pleven[ed, due to the unequal shrinkage of the wood in the various directions. Thus, a boxed heart timber will always check when it dries.

As a general rule a heav5r, dense wood will shrink more than a lighter and less dense one. For example, a piece of Douglas Fir having one-half summerwood (making the piece one-fifth dense) will shrink more than a piece having only one-fifth summerwood. Therefore we may draw these conclusions from the above facts: lst, that the denser the wood the greater the shrinkage;2nd,, that shrinkage does not begin to take place until the,moisture content is below the fiber saturation point; 3rd, shrinkage is almost twice as great tangentially as it is radially, and lengthwise shrinkage is negligible; 4th, vertical grain lumber will shrink less in width than flat grain lumber; Sth, the unequal shrinkage tangentially and radially may cause warping and checking, depending upon the manner in which the lumber is cut; 6th, that the shape of any piece is altered to some extent by shrinkage.

-(Spruce Splinters)

Westwood Club Initiate Thirty Kittens

t/- tnitty Kittens were initiated at the concatenation staged - by the Westwood Hoo Hoo Club at Fall River, Shasta County, California, on June 15 and 16. Vicegerent Snark J. D. Lowe was in charge of the ritual work. Chas. G. Bird, Stockton, Supreme Custocatian, attended the concatenation and also assisted in the initiation work.

Many members of the Order assembled at Fall River on Friday evening, June 14, and were the guests of the ladies of the town who served an excellent turley dinner. A big dance was held that evening in the auditorium.

Fletcher L. Walker, Red River Lumber Co., was general chairman o[ the committee on arrangements and rias assisted by llerbert Smith, Charles Baptie, Archie Allan and vicegerent snark J. D. Lowe.

JOHNSON-ANAWALT BUYS SUNLAND YARD

, The Johnson-Anawalt Lumber Company, Tujunga, Cal., have purchased the stock and buildings of the Sunland Lumber Company, Sunland, and will close this yard because of the proximity of the two yards.