A surgical power tool includes a hand unit and a tool holder. The tool holder engages a hub of a tool to hold the tool during use. One tool holder includes a substantially planar support surface, a pair of spaced-apart sidewalls protruding from the support surface, each sidewall having at least one tab extending from the sidewall toward the other of the sidewalls. A tool clamp, including a post protrudes from the support surface with an enlarged head at a distal end thereof. A lock button protrudes from the support surface, the lock button being depressible toward the support surface. Another tool holder includes an output shaft having a driven end and a free end, the free end of the output shaft having a slot formed therein. A collet is disposed coaxially with the output shaft and is rotatable relative thereto. The collet has a collet wall extending between the first and second ends of the collet. The collet has a plurality of slots in the first end of the collet, a plurality of grooves in an inner surface of the collet wall, and a plurality of internal ridges protruding from the inner surface of the collet wall.