At Fig. 162 is seen the method of securing a tenon by drawbore pinning, employed when it is not convenient to obtain the necessary pressure by using a cramp. The joint is made in the usual manner, and a 3⁄8-in. twist bit is used to bore a hole through piece A. The tenon is driven home and the hole is marked on the side of the tenon (B); the tenon is then withdrawn and the hole bored about 1⁄8 in. nearer to the shoulder than as marked on the separate diagramat C. When the tenon is finally inserted the holes will not register correctly, and if a hardwood pin be driven into the joint it will draw the shoulders of the tenon to a close joint and effectually secure the parts.

Fig. 163 .

Fig. 164 .

Operation of Pegs in Drawbore Pinning.