266, is made by cutting only two sides of the tenon beam.

It was formerly used for lower ends of studding or other upright pieces to prevent lateral motion.
_No.31.A thru mortise-and-tenon_, Fig.

266, is made by cutting the mortise clear thru one member and by cutting the depth of the tenon equal to or more than the thickness of the mortised member.

The cheeks of the tenon may be cut on two or four sides.

It is used in window sashes.
A thru mortise-and-tenon joint is made in the same way as a blind mortise-and-tenon (see below), except that the mortise is laid out on the two opposite surfaces, and the boring and cutting are done from both, cutting first from one side and then from the other.
_No.32.A blind mortise-and-tenon_, Fig.