The mitre shoot is for the same purpose, only instead of being for square corners it is adapted to those at 450, or half a right angle. In case the novice does not know what a mitre is, he may be referred to an ordinary picture-frame, not one of the Oxford pattern. At the corners he will notice that the joint is a diagonal one, so that all the members of the mouldings meet uniformly. To ensure them doing so, the joint must be cut at exactly half a right angle, i.e., for a square-cornered frame; and pieces whether of moulding or anything else joined thus are said to be mitred. Of course, if the frame or work is octagonal or other shape, the angle of the mitre varies accordingly, but it must be half of the whole angle. Thus for a mitred joint of 6o°, each piece would be cut at an angle of 300. The mitre, however, is more commonly required with square corners than with any other, so the ordinary mitre block is made accordingly.
The lower boards are as before, the only difference being in the shape and position of the stop. After what has been said, it seems almost unnecessary to say that it must lie across the board at an angle of 45°, and as one guiding edge is obviously useless, the block is double, so that the end of a moulding can be shot either way. This necessitates the stop block being placed near the centre, as in Fig. 53. A simpler form of mitre-shoot, corresponding to the second shooting-board named, may be made from a piece of board with parallel edges, and a piece the edges of which are also parallel, placed across it as shown in Fig. 54. The mitre-shoot, it must be understood, is only to be used for truing up mitres after they have been cut. To guide the saw while this is being done, a mitre-block or a mitre-box is required. The former is the simpler of the two, and consists of two pieces of wood, on one of which, or rather in the angle formed by the two, the wood to be mitred is placed, while the saw is guided in one or other of the vertical cuts, which, of course, are at the proper angle across. The centre cut observable in the illustration (Fig. 55) is straight, and is for sawing square ends on small pieces of wood. A useful size for the block is about I ft. 6 ins. long, the lower piece being about 6 ins. wide, and the upper one 3 ins. This latter should be of a good thickness, say not less than 11/2 ins., for the wider it is the better the guidance of the saw. The novice will please note that the cuts must be perfectly perpendicular to the bed of the block.
Fig - 53 - Mitre Shoot.
Fig. 54 - Simple Mitre Shoot.
Fig- 55 - Mitre Block.