Furniture 22
Dovetails.
34
.
softwood are customarily wider than in hardwood construction. For hardwood a good rule to follow is that the thickness on the (widest) face of the pins shall be approximately three fourths of the thickness of the wood. It is also good practice to insure that the distance from center to center of the pins is more than twice and less than three times their width. In laying out muliple through dovetails, the two outer or end pins are usually scaled down to half size, plus }i in. for necessary strength. Both pins and sockets can be of equal width if desired, although, as previously stated, many craftsmen prefer the thinner pins- approximately one third of the width of the sockets at their wide ends. Pin widths are seldom cut less than in. wide, however.
For the purpose of laying out a series of sockets, let us assume a drawer front % in. thick and 7% in. wide, with the mating side in. thick. The first thing to do is to check to see that both ends are accurately squared. Since it is the side member that is to be cut into sockets or tails, it is first necessary to estimate the number of pins to be cut in the front. On the basis of a J4 in. thick drawer front, pins }i of this thickness in width would average about Y% in. on their faces. For the distance between centers, if the mean of 2У2. times the width of the pins is selected, the resulting measurement will be i%o НЦ which when divided into the 72in. width of the drawer goes approximately 5 times, that is, 5 centered spaces or sockets.
However, there is to be a half pin at either end of the joint; therefore there will be but 4 full pins in all.
Since a pin of half thickness is usually too thin for safe cutting, it is customary to add an extra % in. at each end to strengthen these half pins. Accordingly, two lines are drawn }i in. in from each edge of the side member to represent the centers of the end sockets, as in Figure 1.34. The depth of the pins is, of course, equal to the thickness of the drawer front, or % in., and this distance is squared off along all four sides of the side member. Many craftsmen prefer to add %c> in. to both pins and tails to form projections that can be dressed flush after final assembling and gluing. In order to divide the space between these two outer center lines, a ruler is laid diagonally across the space until it is readily divisible by 4. By means of a try square at the joint or outer end of the piece, parallel lines are brought down to intersect the outer edge of the member, marking the centers of the four pins Because the width of a pin at its narrowest or deepest point is rarelv less than
Fig. 1.34. Laying out a dovetail.
be edge of the board (Figure
the depth o:
CABINETMAKING
the socket the maximum thickness of % in. is next centered and connecting li scribed between the joint edge and the back line to form the complete pin. alternate method is to mark only the width of the pin along the board's edge; th by setting and clamping a bevel to register a slope of i to 6, the parallel sides of pins are projected across the depth line.