297, D, if they are to be used.

Lay out and cut the tenons and mortises for the end rails and back rail.
The proper form of the tenon is one with a wide shoulder above it so that the top of the leg above the mortise will not shear out.

The rails should be set near the outside of the leg so that the tenon may be as long as possible and the portion of the leg inside it as strong as possible.

A haunched mortise-and-tenon joint, Fig.

267, No.