A hand tool comprises: a body; a handle extending from the body; a hand-operable lever pivotally connected to the body and pivotable from a resting position towards the handle to a working position; a shaft extending through the body along a longitundal axis, and movable between forward and reverse directions along the axis relative to the body; a shaft drive mechanism mounted to the body and operatively connected to the shaft and lever such that pivoting of the lever to the working position causes the shaft drive mechanism to incrementally advance the shaft only in the forward direction; and a shaft release mechanism mounted to the body and comprising a shaft locking member operatively connected to the shaft and lever, wherein the shaft locking member is movable by the lever between a locking position and an unlocking position, and wherein movement of the lever from the resting position away from the working position moves the shaft locking member to the unlocking position and enables the shaft to be moved in the reverse direction.