A surgical instrument (10) including a tool (14), a handpiece (12), and a locking member (70a). The handpiece includes both a coupling member (130) configured to cooperate with the tool, and a driver (102) for rotating the tool. The locking member is movable from an unlocked position to a locked position in response to centrifugal force generated during rotation of the locking member. The locking member is configured to secure the tool to the handpiece when in the locked position. The locking member can include flexible expansion tabs, f. ex. first and second (86a, 88a) flexible expansion tabs, or first, second and third (86b, 88b, 94b) flexible expansion tabs. The locking member can include a slot (90a) extending along the entire length of the locking member for snap-fit coupling to the tool.
