It is used in boxes and gives plenty of surface for gluing.
_No.27.A dado, tongue and rabbet_, Fig.

266, is a compound joint, made by cutting a rabbet on one member, Y, and then a dado in this rabbet, into which fits a tongue of the other member, X.It is used in machine-made drawers.
_No.28.A dovetail dado or gain_, Fig.

266, is made by cutting one or both of the sides of the infitting member, Y, on an angle so that it has to be slid into place and cannot be pulled out sidewise.

It is used in book-cases and similar work, in which the shelves are fixed.
To make this joint, first lay out the dovetail on the member to be inserted, called Y, thus: Across one end square a line (A B, No.
28), at the depth to which this member is to be dadoed in.

Set the bevel-square at the proper angle for a dovetail, Fig.250.Score this angle on the edges of the member, as at C D.Cut a groove with a knife on the waste side of A B.Saw to the depth A C, and chisel out the interior angle A C D.
Then lay out the other member, X, thus: mark with the knife the proper place for the flat side of Y, square this line across the face and on the edges as for a simple dado.