The backsaw (Fig. 42) is used upon fine work; it is filed like a cutting-off saw, but the teeth have rather more hook, and it often has as many as fifteen teeth to the inch, though a twelve-tooth saw is as fine as is generally used. The thick back is to stiffen the blade of the saw, and if the latter becomes sprung, a light blow upon the back, as though to drive it upon the blade, will usually straighten it.
(B.) In buying a saw, select one which is thicker upon the cutting edge than upon the back; this allows the saw to be used upon very fine work with little or no setting. See that the handle fits the hand, and that the saw hangs to suit, or “feels right.” This is a matter concerning the balance and the weight of the tool, which cannot be described, but which any one accustomed to using tools will miss if a tool not possessing this quality is placed in his hand.
A saw blade, unless very short and thick, should bend so that the point may be put through the handle, and upon being released, instantly resume its shape. It should bend evenly in proportion to the width and the gauge of the saw, and should be as thin as the stiffness of the blade will permit, as a saw of this sort cuts less wood, and therefore runs with less resistance. A compass saw, being softer, is not expected to stand the above test.
A 26” or a 28” blade is best for a heavy rip or cutting-off saw to be used upon coarse work; but for fine work, a 22” blade, commonly known as a “panel saw,” is a convenient size, though a 20” or a 24” blade is preferred by many workmen.
Fig. 43.—Use of the Saw.
Showing the method of using a try-square to insure accuracy.
(C.) A hard saw is best for fine work, but for general work most workmen prefer a saw of medium hardness, as the teeth of a hard saw are apt to break in setting, and its edge, if it comes in contact with metal, requires filing just about as quickly as that of a soft saw, and is much more difficult to sharpen. If always filed by an expert filer, a hard saw is superior in every way to any other.
Fig. 44.—Reset Saw
Handle.