warping, as shown in Fig. I (the under side of a battened drawing board) and in the enlarged detail, Fig. 2; and the working edge (left-hand end) inlaid with an ebony slip to prevent wear of the softer pine.
A cheaper kind is the clamped board. Figs. 3 and 4. These are not so reliable as the above, for the shrinkage of the panel causes the ends of the clamps to project, and if the square is used from that, edge a faulty line is produced. They will, however, answer the purpose of beginners for some time, if they are trued up occasionally, and they are much cheaper than the battened variety.
A very reliable form of board, which the author designed for his own use some years ago, is shown in Fig. 5. It is easy to make, and has the advantage that both sides of the board may be used, and there is no possibility of the panel splitting. The board is glued up and cleaned off to the required size, then the ends are grooved exactly one third of the thickness. Two clamps of hard-wood, straight-grained mahogany for preference, about the same thickness as the board, are prepared with a similar groove to that in the board, when these are fitted on as shown, just" hand tight," they will allow the board to swell or shrink, but prevent it casting. Of course they must be fitted with dry joints—• that is, not glued. The depth of the working edge must be a trifle more than the thickness of the stock of the T- square used.
A useful attachment to the board, which the joiner student can make for himself, is the " copy " holder shown in Figs. 6 and 7. These may be two thin strips of mahogany, one attached directly to the back edge of the board by means of a round headed screw, the other pivoted similarly to a short block or fillet, equal in thickness to the opposite slip, and fixed to the board so that the first slip folds down within it, whilst the second folds over the first. They should work stiffly, and the edge of the hoard and the fillet should be bevelled to throw the holders backwards when open. A tilting bar (see Fig. f>), about 18 in. x 2 in. x 2 in. is
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