Drill Archimedean

A hand tool which gives reciprocating motion to a drill. It consists of a rod with a spiral 'quick' thread, having a handle pivoted at one end and a drill holder or chuck at the other. A sliding nut on the threaded rod imparts motion to the drill. Some drills of this type have the nut formed in the base of the handle, the rod passing into the handle as pressure is applied and returning by means of a spring when pressure is released, thus giving reciprocating drill action. Another type of drill often referred to as archimedean is the drill with cords and inertia wheel. This is also called a 'bob' drill or 'upright' drill, the weighted bob causing the cords to wrap around the stock on the overrun, motion being imparted as the handle is pressed down. This type is normally used only by jewellers and casemakers.