Lay out the thickness of Y on the face of X by superposition or otherwise and square the face and edges, not with a knife but with a sharp pencil point.

Gage the required depth on the edges.

Now with the bevel-square as already set, lay out the angle A C D on the edges of X, and across the face at C score a line with knife and try-square.

Cut out grooves in the waste for the saw as in a simple dado, and saw to the proper depth and at the proper angle.
Chisel or rout out the waste and when complete, fit the pieces together.
[Illustration: Fig.250.Laying Out a Dovetail Joint.] _No.29.A gain joint_, Fig.

266, is a dado which runs only partly across one member, X.In order to make the edges of both members flush and to conceal the blind end of the gain, the corner of the other member, Y, is correspondingly notched out.