A power tool includes an outer housing having a drive unit support portion and a handle portion, an inner housing positioned at least partially within the outer housing, and a drive unit positioned in the drive unit support portion, the drive unit including an output member. The power tool also includes a power screw mechanism with a nut fixed relative to the outer housing and a screw coupled for co-rotation with the output member and axially movable relative to the output member. The screw is in threaded engagement with the nut such that the screw moves axially in response to rotation of the screw relative to the nut. The power tool also includes a working assembly coupled to the inner housing for movement in response to axial movement of the screw.