Self-Locking Pin Chuck
This lathe chuck features an ingenious self-locking mechanism that allows quick and easy mounting and dismounting. It works equally well in both forward and reverse rotation. The chuck is ideal for projects with predrilled, centered holes, such as candlesticks, bud vases, wooden flutes and the like. You simply mount the hole over the end of the chuck to turn the profile.
To make the chuck, start with a length of mild steel bar. Turn a Morse taper on the tail of the chuck to fit your headstock. Then turn the head of the chuck to fit a predrilled hole in your turning blank 3/4 in. for example. Now file a flat spot on the head, as shown in the sketch. The depth of the flat should be just a bit greater than the diameter of the locking pin. The locking pin is nothing more than a piece of nail almost as long as the flat.
To use the chuck, first drill a hole the same size and depth as the head of the chuck in your workpiece. With the locking pin centered in the flat, slip the workpiece on the chuck and rotate the work until the pin wedges and locks the workpiece in place. The chuck will lock in either direction be sure you lock the work opposite the way your lathe will be turning. If you don’t, tool pressure will unlock the chuck while you work.
John G. Martin, Cumberland, Maine
Fine Woodworking Magazine, August 1986 No. 59