The chisel enters so largely into the work of the pattern maker in paring and shaping patterns that the quality of the tool should be of the best. While carpenters' chisels are made in several styles, they may be divided into two general classes, socket-handled chisels, and firmer or paring chisels. The former are illustrated in Fig. 42, and are used for framing, and for very heavy work of all kinds in which the use of a mallet is necessary. The common firmer or paring chisels, two styles of which are shown in Fig. 43, an- the best all-round chisels for pattern work. Being lighter and thinner than the others, they are better adapted to the light work on which they are used; moreover, when used with care, they will answer every desired purpose, even for heavy work or with a mallet.
The beveled-edge chisel shown at a, Fig. 43, is greatly to be preferred. It is lighter than the other kind illustrated, and the square angle being removed, the workman is enabled to reach into angles and under projections difficult to reach with a square-edged tool. A set varying in width from 1/8 inch to 5/8 inch by eighths, and from ¾ inch to 1½ inches by quarters, nine chisels in all, will be found useful.
The paring gouges used in pattern making are ground or beveled on the inside, as shown in Fig. 44. These gouges are made in regular, middle, and flat sweeps. They are indispensable for working out core boxes and other curves.
In selecting a set of paring gouges, they should be not only of assorted sizes, but of different sweeps, so as to work out semicircles and curves of different radii.
The common firmer gouge, illustrated in Fig. 45, is a useful tool for rough or heavy work, but in general its use can be dispensed with in pattern making.
The manner in which the chisel is used is so obvious and simple that any instruction in that direction would seem unnecessary. We shall only say in a general way that in using a chisel on a flat surface or in a recess it should always be held with the flat or bock of the chisel against the work; and, whenever possible, it should not be pushed straight forward or straight through an opening, especially when paring across the grain of the wood, but should be moved laterally at the same time that it is pushed forward, as indicated by the dotted lines in Fig. 46. This insures a shearing cut, which, with care, even when the material is cross-grained, will produce a smooth and even surface.
As an exercise for acquiring the free use of the paring chisel, there is nothing better for the beginner than the simple half-lap joint shown in Fig. 47.
The shoulders or the ends of the openings must be cut with a back saw. The opening is then cat oat and the shoulders smoothed with a wide chisel, and a perfect fit obtained by continued trials.
The two dove-tail joints shown in Fig. 48 may be attempted, after having succeeded with the half-lap; and these exercises should be continued by the student until such control of the chisel is attained that this and similar work can be done with ease and certainty. For laying out work of this kind the blade of a pocketknife or bench knife should always be used. This gives a clean, sharp-cut angle for the meeting sides of the joints, which cannot be obtained if a scratch-awl is used. The awl tears and breaks the fibres of the wood, producing a rough, ragged angle, which, on fitting, cannot produce a smooth and close piece of work. A pencil is equally objectionable because of the indefinite dimensions given by its use.
An assortment of four to nine carver's gouges, front bent as shown in Fig. 49, will be found necessary for working out short, deep curves, and in places where a straight gouge cannot be used, as in the core boxes for a globe valve, shown in Figs. 222, 223, 227, 228, and similar work.
The full set consists of nine tools, the curves of which are numbered from 24 to 32. The two extremes, Nos. 24 and 32, are shown in Fig. 49, and also the shapes of the curves of the seven intermediates, Nos. 25 to 31 inclusive.
If desired, to save expense, each alternate tool might be omitted from the set, only the odd numbers 25, 27,29 and 31 being selected. For ordinary work these will be found sufficient.