for flooring are 6 in. by 2 in., 6 in. by 2½ in., 6½ in. by 2½ in., 7 in. by 2½ in., and 7 in. by 3 in. When 3-in. by ⅞-in. flooring is being cut and wrought, the most suitable sized batten is 7 in. by 3 in., which gives six pieces, three saw cuts being sufficient—namely, two deep and one flat. This is when wrought single with the flooring machine. When run double with the machine two saw cuts through the depth are sufficient. The flat cutting in this instance is done with the flooring machine. The double working of flooring and lining with machinery, though much the quicker way, is not so satisfactory as the single method, for each alternate board has to be reversed, besides the further disadvantage, if the battens are waney, of the groove being always on the waney edge. Similar sized flooring (⅞ in.) can also be cut from 7-in. by 2½-in. battens. Two boards may be cut ⅞- in. in thickness and one ½ in., thereby utilising the whole batten; 5½ in. by ⅞-in. boards are taken from 6-in. by 2-in. material; 3-in. by 1⅛-in. from 7-in. by 2⅛-in., 3-in. by 1⅛-in. from 7-in. by 3-in.
Fig. 365.—Ordinary Direction of Grain in Floor-Boards.
Operation of Floor-Board Planing Machine.—The fixed cutters or face irons of a flooring machine produce the best and smoothest work. These tools operate on the under side of the boards; therefore the freshly sawn side should be placed downwards to receive the finishing, which the face irons accomplish. The revolving top scutching-block is not so much used for dressing as for bringing the boards to an exact thickness. So long as one side of the board is well dressed and of accurate thickness, it is not important to have the other side so well done. Some machines have fixed planers on the upper side, but such cannot bring the stuff to an accurate thickness like the revolving scutch-block. It is heavy work for fixed cutters to reduce boards 118 in.; the scutching-block, however, can easily take ¼ in. off. With evenly sawn wood heavy cutting has seldom to be resorted to. The leading advantage of the scutching-block compared with fixed cutters is that the block makes an irregular surface parallel, whereas fixed cutters follow the uneven nature of the board, and do not alter any irregularity which it may have. There are many cutter heads for the formation of the tongue and groove. The face-iron side of the groove and tongue should project a little more than the scutched side; by this means the faced side of the flooring, when driven home and placed in position, has a better joint than it otherwise would have. The "Shimer" patent heads make the finest work; with a feed speed of 60 ft. or 80 ft. per minute undue chipping is very rare with the "Shimer" patent. A good machine can run from 9,000 to 11,000 sup. ft. of 6-in. or 6½-in. by 1⅛-in. flooring per day, or 4,000 sup. ft. of narrow flooring. All 1⅛-in. material is taken from 2½-in. battens, whether broad or narrow. Flooring above 1½ in. thick is sometimes run with two grooves instead of one, and slip feathers are employed in place of the solid formed tongue. This plan saves ½ in. on the breadth of each board.
Fig. 366.—Direction of Grain for Least Shrinkage of Floor-Boards.
Stacking Floor-Boards.—Finished flooring, no matter how well it may be stacked and pinned, is always liable to become twisted whilst being seasoned. To obviate this, the material should be sawn, pinned, and stacked in the rough. Let it season for six or eight weeks; then finish it with machinery. Work done in this way can be stored in bulk under cover without being pinned or ventilated. Flooring wrought on this principle does not twist, cast, or shrink like material finished and stacked at one operation; it is, moreover, much more easily laid. This rule applies also to lining. Red deal flooring is not so generally wrought for stock as white, for
