Fig. 110.
Carpenters in working on large timbers lay the steel-square diagonally across so that there are twenty-four divisions from arris to arris. They then mark off the timber at seven and seventeen inches. [Fig. 110]. These numbers, while not mathematically correct, are near enough for practical purposes. In planing the arrises off, the piece may be held in the vise or placed against the bench-stop. [Fig. 111]. Care must be taken not to plane over the lines, for not only is the one side enlarged, but the adjacent side is lessened, thus exaggerating the error. (3) Judging with the eye the amount to take off, plane the eight arrises until there are sixteen equal sides.
Fig. 111.
Again plane the arrises, making the piece thirty-two sided. On a small piece this will be sufficient; if the piece is large, the process may be continued until the piece is practically a cylinder. (4) To finish a small cylinder wrap a piece of sandpaper around it, rub lengthwise until the surface of the wood is smooth and the piece feels like a cylinder when revolved in the hand.
59. The Spokeshave.
—[Fig. 112]. The spokeshave is used principally to smooth curved surfaces. It may be drawn toward or pushed away from the worker, whichever is more convenient. By means of screws, the blade may be adjusted to take light or heavy shavings. The spokeshave is practically a short plane with handles at the sides, and in using it the aim should be, as with the plane, to secure silky shavings of as great length as the nature of the work will allow.
Fig. 112.