US Patent 7131473 Programmable coping bit

A coping bit capable of being easily modified to cut profiles having tenons of varying lengths is provided. The coping bit includes an axially extending primary drive shaft and a first cutting member fixed on the primary drive shaft. An axially extending secondary drive shaft having an upper and a lower portion is removably mounted on the primary drive shaft for rotation therewith, and a second cutting member is mounted on the secondary drive shaft in spaced relation to the first cutting member when the secondary drive shaft is mounted to the primary drive shaft.