Fig. 34 represents the tenon, sash, carcase, and clove-tail saws, which may be spoken of collectively as back-saws. The tenon saw is the largest, and the dove-tail the smallest of the group. These saws derive their distinctive titles from the description of the work for which they are employed.

The sawing-block is much used for guiding the back-saws when cutting the extremities of mouldings, or the separate parts of light frames to a mitre joint. The block is formed like a trough, with open ends. The sides must be quite parallel, both inside and out, and three saw-kerfs are very carefully cut in them with the back-saw. The kerfs near the right-hand extremity of the block are exactly opposite each other, consequently the saw will move in them at right angles to the sides, and cut the ends of the work square. The other kerfs are made at angles of 45 degrees, and slope in opposite directions for cutting mitres at the ends of pieces which are to be united at right angles. If the kerfs be not exactly vertical, they are worse than useless, as the saw is constrained to follow their inaccuracies, which are imparted to the work.

To use the sawing-block, it is only necessary to place the work inside, holding it firmly against the further side, with the pencil-mark indicating the line of division exactly opposite the kerf. The saw must be used with care, to avoid widening the kerfs in the block.

When several pieces of equal length are to be cut off, a small block of wood, called a stop, is temporarily attached to the sawing-block, which thus saves the labour of measuring and marking out, at the same time ensuring greater accuracy. The "shooting-boards," represented on pages 48 and 49, are sometimes used in lieu of the sawing-block.

The kerfs for the guidance of the saw are made in the "strip" and the work is supported on the "bed." This arrangement is very convenient when it is necessary to saw the ends of the work immediately after "shooting its edges."

The spokeshave (fig. 48) is somewhat similar in its action to the plane; but owing to the absence of the guide principle which exists in the "sole" of a plane, it cannot be employed for working flat surfaces, as it descends into all the inequalities, instead of removing them. This tool may be compared to a knife held at a very low inclination, and indeed the pitch is lower than that of any of the surfacing planes, being only about 25 or 30 degrees. The spokeshave works well in the direction of the grain, but it is only applicable to small rounded or curved works which cannot be wrought by the plane. The blade is usually secured to the stock or handle by two spikes or tangs which fit tightly into the wood. Set screws, s, s (fig. 48) are sometimes employed to facilitate the adjustment of the blade, which must be regulated as carefully as an ordinary plane-iron. The extremities of the stock are rounded into convenient handles, which are grasped in right and left hands respectively. The operator applies the tool to the work with the edge of the cutter towards him, and removes shavings by drawing the instrument forward.

Fig. 48.

While speaking of the various tools used in carpentry and joinery, we may observe that the firmer chisel (fig. 4) varies in width from about 1 /16 inch to 2 1/2 inches, and is generally used for finishing portions of the work which may have been left rough or ill-defined from the saw, etc.

Fig. 49.

If the work be light, it is held down on the bench by the left hand, and the chisel is applied by the right. The flat side of the chisel is placed next the work, with which it must form a slight angle, to enable the edge to penetrate the wood. When the work is large or heavy, it must be fixed either by the "hold-fast" (n h, fig. 1, page 7), or in the screw-chops (C). If increased power be required, the tool is pressed forward by the workman's shoulder, and when this fails to make the instrument advance, the mallet (fig. 49) must be employed to drive it into the material.

Fig. 50.

The mortise-chisel (fig. 50) is employed, as its name implies, for making the hole or mortise for the reception of the tenon. This tool is nearly square in section, but unlike the firmer chisel, its cutting edge is formed on a narrow instead of a wide side, to enable it to cut a contracted hole, and yet retain sufficient strength to withstand the blows of the mallet.

The gouge (fig. 51) acts in a similar manner to the ordinary chisels, but owing to its semicylindrical shape, it is especially qualified for hollowing out deep cavities. It may, like the chisel, be driven forward by the hand when the resistance is not great. These tools are only suitable for light works, and must not be forcibly struck by the mallet; otherwise the handles maybe split, as the shoulder at the root of the tang causes the wood of the handle to spread, and will eventually split it. The chisels used by carpenters are formed with sockets instead of the tangs and shoulders. The handle is fitted tightly into the socket, which effectually preserves it from splitting, notwithstanding the violent blows which must be struck to drive the instrument into the wood when cutting the large mortises, etc, frequently required in heavy carpentry operations.

Fig. 51.

Fig. 52.

The bevil (fig. 52) is somewhat similar to the square (fig. 16), and differs from it only in not having a permanently fixed blade. The square, as we have before stated, can only be used for testing the truth of right-angled surfaces, which, to be correct, must form an angle of 90 degrees.