Paring away the waste material with a chisel is the next step, and this is shown at [Fig. 68]. The work may be chiselled either in a vertical or a horizontal position. The horizontal position is the easiest for the amateur who has a vice or handscrew, because he may hold the work securely with a mechanical device and so avoid the unnecessary risk to his fingers.
Take the chisel and cut away A, [Fig. 68]; now turn the chisel and cut away B; after which keep the chisel horizontal and cut off "the top of the hill," as it were, C. Repeat the three operations until you gradually pare the wood away exactly to the gauge line. When chiselling, if you find a tendency for the work to chip or crumble at the back edge owing to the forward pressure of the chisel, turn your wood round and begin to cut from the other edge, allowing the chisel to finish paring at the centre.
Joints Other than a Right Angle.—If the halving joint is at an angle similar to the sketch shown at [Fig. 69], great care will have to be exercised in the use of the chisel, owing to the change in the direction of the grain of the wood. The arrow marks in this sketch distinctly indicate the direction in which the chiselling must be done so as to give a smooth result. This change of direction for cutting also applies to the bottom of the halving joint.
Cutting Joint at End of Timber ([Fig. 70]).—Should the halving joint be used at the end of a piece of wood, as at [Fig. 30], the waste material may be roughly sawn away and the flat surface trimmed up with a chisel.
To saw out this type of halving joint, proceed to work the shoulder line as already described; then place the piece of wood obliquely in the vice as shown ([Fig. 70]) and proceed to saw down the vertical line, carefully watching the gauge line to see that you saw on the waste side of the lines. Then turn the piece of timber with its opposite edge towards you, and again use the saw as illustrated. You will this time only have to watch the gauge mark on the edge of the wood, because the saw will readily follow in the saw kerf already made. Now place the wood vertically in the vice, and keeping the saw in a horizontal position, saw down to the shoulder line.
Halving joints properly made and fitted should knock together with the weight of the clenched fist; the use of a heavy mallet or hammer will deface the work.
Fig. 71.—Joints used in the erection of a Queen Post Roof Truss.