Abstract: Operator access to the zone at which workpieces are struck in a drop hammer is temporarily but reliably blocked by a sturdy mechanical guard throughout every period when the hammer may commence and complete its fall; a unique physical linkage, between the guard and a safety-dog lever which must be manually turned in order to release the hammer, insures that the safety guard must have been shifted from an out-of-the-way position into a protective orientation before the hammer can drop.