A chuck assembly for a rotary power tool includes a body rotatable about a central axis, the body including a plurality of openings and a first set of threads, a plurality of jaws received within the plurality of openings in the body; a collar surrounding the body, the collar including a stepped portion configured to engage the plurality of jaws to limit radial movement of the plurality of jaws, a second set of threads coupled for co-rotation with the collar and engageable with the first set of threads on the body such that rotation of the collar relative to the body causes the collar to move axially along the body, and a spring biasing the collar such that the stepped portion is biased into engagement with the plurality of jaws.