Sherline 3217 Gear Tooth Cutter Holder
The gear tooth cutter is included with the purchase of the indexing attachment and can also be purchased separately. It looks much like a small fly cutter and includes a 1/4″ high-speed steel tool blank that you can custom grind to the particular gear tooth shape you need. The cutter can be used in conjunction with both the indexing attachment and rotary table. The #1 Morse taper on the shaft is held in the spindle with a drawbolt and special washer.
This is an economical alternative to round commercial involute gear cutters. Also, grinding your own cutter shape, while somewhat time-consuming, offers unlimited possibilities for matching existing gear tooth shapes when making replacements for gears with broken teeth. Simply use your existing gear as a pattern when grinding the cutter shape. With a little practice and skill, goodcutters can be ground on a regular bench grinder.