EXERCISE NUMBER 7.DOVETAILING.
One of the most important methods employed by the joiner is that termed dovetailing, which is of three kinds, namely, common, lap, and miter. Common dovetailing (see Fig. 97) shows the form of the pins or projecting parts, as well as the excavations made to receive them. Lapdovetailing is similar to this, but in that system the ends of the dovetails of theside A, Fig. 98, are shortened, and the recesses which are to receive them in B are not cut through when joined together; only the ledge is visible on the return side.
Fig. 97.
Fig. 97.
Fig. 98.
Fig. 98.
Fig. 99.Fig. 100.
Fig. 99.
Fig. 100.
Miter dovetailing (sometimes also called secret dovetailing) conceals the dovetails, and shows only the miter at the edges. The manner in which this joint is made will be understood fromFig. 99, in which the two parts A and B are given, each part being lettered to correspond with the position it is to occupy when the sides are joined. Concealed dovetailing is particularly useful where the faces of the boards are intended to form a salient angle; that is, one which is on the outside of any piece of work; but when the faces form a re-entrant angle, that is, a joint to be seen from the inside, common dovetailing will answer best; for, first, it is stronger, because the dovetails pass entirely instead of only partly through; secondly, it is cheaper, for the dovetails which go through the whole wood take up much less time inworking than where a miter has to be left; and further, if well executed, the dovetails are, by the very nature of the work, concealed internally.
Fig. 100shows a variation of the common dovetail, used in attaching the fronts of drawers to the sides, and for similar purposes.
Fig. 101.
Fig. 101.
InFig. 101is given the working drawing of the common dovetail, andFig. 102, A-Bshows the details of each piece.
The stock can be prepared in one piece (having it long enough so that if a poor joining is made, the dovetails can be cut off and new ones cut on this piece). After planing, cut in two, square one end of each piece (the ends to be joined). To lay out the work, it is advisable to lay out the piece with the pins or tenons first. From the squared end measure in the thickness of the side; then mark on both sides, using the knife to draw the lines.
Fig. 102.
Fig. 102.
On the face side (which is the side that would be toward the inside of a box) lay off the lines shown for the pins in the detail marked A,Fig. 102. These lines can be drawn from the working edge with a gauge, or, if the ends are perfectly square, the square can be used (the lines being parallel with the edge). From these lines will be drawn the oblique lines across the end with the bevel set at a taper of 1 inch to 4 inches. The bevel can be set by the steel framing square, by the methods already given.
After drawing the lines saw down the required depth on the outside of the line, and remove the pieces between the pins or tenons by firstboring a hole through the piece to be removed, then cutting from both sides with the chisel.
Fig. 103.Fig. 104.
Fig. 103.
Fig. 104.
(The boring is done with the brace,Fig. 103, and the bit,Fig. 104. Bits are of different forms;Fig. 105shows a number of different styles).
It will be necessary only to draw the lines across the end of the piece markedB, Fig. 102, as the marking of this piece for the recesses will be made by holding in position the piece already cut, and scribing or marking the pins or tenons, then squaring the lines across the end.
Great care must be taken in sawing the mortises if a perfect fit is desired. This can be done only by sawing on the inside of the line, cutting the lines in two. The pieces should go together by light driving, and should be perfectly square on the inside. If the joint is satisfactory take apart and glue together. After the glue is dry thejoint can be smoothed and the ends of the pieces cut off and squared to the proper dimensions given inFig. 101.
Fig. 105.
Fig. 105.