The drawing of this exercise need only be the isometric projection. Plan and elevation can be made instead, however.

A piece of yellow deal about 11 1/2 ins. long, 1 3/4 in. wide by 1 in. thick, will be required, and should be first planed true on faces and edges, to the dimensions shown.

Mark the line halfway from the end where the wood is to be cut in halves, and then draw cut lines to indicate the shoulders of the 'dovetail' (fig. 187), as the wedge-shaped end is appropriately called. The pencil lines on the end of the wood, for the sloping sides of the dovetail, should be made to incline very slightly towards each other - so little, that no measurement can really be given, but the importance of this slightly diminishing dovetail will be appreciated in making the joint.

On the face and opposite edges of the other half of the wood, square two pencil lines across the thickness, and the width of the face apart, \\ in. Halfway down these lines make gauge lines for the depth of socket.

Saw out the dovetail, commencing by sawing down the gauged line halfway in the thickness in the same way as for a tenon (figs. 170,171,172).

The oblique sides of the dovetail should now be sawn down, in this case holding the saw horizontally, and finally cut the shoulders. Saw the wood in halves, and apply the dovetail to the pencil marks on the face side of the other half. The side of the dovetail which is on the wood is now slightly smaller than the face side, and along the line of contact between the dovetail and the surface of the socket piece, a cut line should be made with the corner of a chisel, as in fig. 189. The shape of the socket is now obtained and can be carefully sawn and pared out. Press the dovetail into the socket and clean the joint off. The advantage of tapering the dovetail will be at once apparent, as the top of the joint when pressed flush with the surface of the other half will probably give a very good close fit.

Fig. 187 shows the setting out.

Fig. 188 shows the dovetail cut and face of the wood reversed.