Fastening The Box Bottom. The side and end pieces of a box, when nailed together, may not be exactly rectangular, although each piece has the required length, and the fastening cannot be depended on to retain them with certainty in any given form. But when the bottom piece is added, all parts become fixed. It is, therefore, important that the rest of the box be in proper form when the bottom is nailed.

The bottom piece has been cut the same length as the side pieces, and it has a working-edge with which both ends are square; it is a little wider than is necessary, but this can be made right in finishing the box.

Place the bottom piece with the working-face inside, and the working-edge even with the outside edge of one of the side pieces, as shown by Fig. 174, and drive the nails a. Now since the angles b are right angles, the end pieces of the box, in order to be square with the side, to which the bottom is already nailed, must agree with the ends of the bottom piece. If they do not agree, but slip past, as shown by Fig. 174, slight pressure will spring them to place, after which nails may be driven at the points c.

The nails in the bottom of a box must be so placed as to avoid those which hold the sides to the ends. No nail can be driven at the corners d.