Woodwork Joints | Page 9

cases be left at least 1/4 in. longer than necessary and levelled off with the saw, plane and chisel after the joint is put together. (See Method of Cutting in Fig. 92, page 47.)
When the piece A has to have a bridle joint fitted at each end, it is customary to cut the timber about 3/8 in. longer than necessary, and mark the shoulder lines C to the exact length, after which the joints are cut. This leaves the ends standing over the horizontal rails, and, after fixing the complete frame together, the small projecting ends are levelled off flush with the cross rails.
GAUGING.--After squaring all the shoulder lines round the timber with the knife and try square, the mortise gauge should be set so as to strike the two gauge lines marked G, Figs. 83 and 84, at one operation. If the worker does not possess a mortise gauge the lines may be marked at two distinct operations with the aid of the marking gauge (Fig. 82). The gauge should be adjusted so as to mark the wood into thirds, and the stock of the gauge (the portion of the gauge containing the thumb screw in Fig. 82) must be used from the face side of the timber when gauging up the whole of the pieces forming a frame. The face mark on the work is indicated by a glorified comma, and the edge mark is shown by X, as in the various illustrations. Fig. 82 shows the method of holding the gauge in the right hand whilst gauging the lines on the work.
[Illustration: Fig. 81.--Bridle Joint, open and closed.]
[Illustration: Fig. 82.--Gauging the Timber.]
The joint, when marked out, will appear as at Figs. 83 and 84, and the portions which are to be cut away may be shaded with a pencil as indicated; this will prevent mistakes arising whilst cutting the work, especially by one who is not thoroughly familiar with the joint.
The distance A B, in Fig. 84, must not be less than the distance A B in Fig. 83.
[Illustration: Fig. 83., Fig. 84. The Two Parts of the Joint Marked.]
BORING AWAY WASTE.--Examine Fig. 84; the shaded portion in the centre has to be cut away, and it will greatly facilitate the removal of this waste piece by boring a hole with a twist bit at the position shown. The twist bit should be about 1/8 in. less in diameter than the width between the gauge lines G. The easiest method of boring out this hole is shown at Fig. 85, which gives the correct position of the worker.
[Illustration: Fig. 85.--Vertical Boring previous to Chiselling.]
SAWING.--The wood should be put in the vice as Fig. 86. Taking up a saw, with the index finger on the side of the handle, commence sawing, and proceed until you come to the position indicated by the dotted hand and saw A; this will leave a saw kerf or cut running diagonally from the shoulder line to corner of the wood. Release the vice and refix the wood so that it leans in exactly the opposite direction to Fig. 86; then reverse your own position and repeat the sawing, so as to cut another diagonal saw cut from the shoulder line to the corner. Fix the wood upright, as shown at Fig. 87, and saw as shown, when you will find that the saw has no tendency to run out of the guide cuts already formed by the method used at Fig. 86. Remember, when commencing to saw at Fig. 86, that it is necessary to saw inside the gauge line; otherwise the joint will be too slack, owing to the amount of sawdust removed by the thickness of the saw blade. The index finger on the side of the saw, pointing in the direction of the saw cut, will greatly help the worker to saw in a straight line, as it is natural to point with this finger to any object that is to be aimed at.
[Illustration: Fig. 86.--How the Saw is held for the first Cut.]
Cut down the other line in a similar manner, and then with a chisel of suitable width carefully chop away the waste material. The wood may be placed edge way upon the bench, or in the vice, and the chisel should be held vertically. The hole which has been bored with the twist bit will allow the chips which are cut away to offer little or no resistance to the chisel blade. The chiselling should not all be done from one side, or a chipped under-edge will be the result; it is better to chisel the work until half-way through and then turn the other edge of the wood uppermost and again begin to chisel from the top. This method will finish the cutting in the