Standard Boring Ring—Match standard rings to your lathe chuck’s diameter for machining the center of your jaws. Line them up with your jaws by sliding the pins along their curved tracks.

Adjustable Boring Ring—Adjustable rings fit a range of lathe chuck diameters. The pins are mounted to straight tracks—slide them in and out of the ring to adjust the diameter. They are also reversible, which allows you to machine both the inside and outside of your jaws. When the pin screws are outside the ring, you can machine the center of your jaws. Flip them around to the center of the ring to machine the outside of your jaws.