Setting Out And Marking
It is a safe rule, when setting out a bridle joint, to divide the thickness of the timber into three equal parts. This will leave the timber on each side of the tongue equal to the thickness of the tongue, thus giving uniform strength to the joint. The bridle joint is chiefly used for connecting the internal parts of wooden frames. It is stronger than the halving joint, and, owing to its peculiar construction, requires little in the way of pegs, screws or nails to secure it in position. illustrates the joint, both open and closed.
To understand the method of setting out and marking, glance at the sketch, . It is not necessary that the bridle piece A be the same width as the cross piece B; but it must be remembered when setting out the joint with the marking knife or pencil that the width marked W on piece B must be equal to the width W on the piece A. The timber should be fairly accurately sawn or planed to the same thickness, and all edges should be square and true.
The wood is placed upon the bench, and the joint marked out by using a marking knife or penknife blade and the try square. A knife blade is much better than a pencil, as the sharp edge severs the fibres of the wood and gives a finer line than the pencil. It is not always necessary to exactly square and trim the end of piece A; it may with advantage in many 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 , 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.
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