Figure 3-77. Procedure for making a lock corner joint on 3/4" stock. Accuracy is critical. (A) Cut a 1/8" x 1/8" dado, 5/8" from the edge. (B) Cut a 1/8" x 1/8" rabbet. (C) Cut a 1/8" x 1/2" rabbet to form the 1/8" x 1/8" tongue. (D) Form a slot 3/8" x 3/4". (E) Cut off one side of the slot and cut a 1/8" x 1/8" dado.
Joints of this type are a challenge to do, but they hold together beau-tifully. Figure 3-77 shows the typical procedure on 3/4" stock. Accuracy is critical.