Abstract: A tool for folding sheet metal edges includes the following. A pneumatic hammer has a stepped barrel with an externally cylindrical proximal portion and a reduced-down distal portion externally formed with inverse spring thread. A plunger has a shank with a work-striking head, a spaced away butt end that loads into the hammer barrel, and an intermediate axial-stop enlargement disposed therebetween. A spring for retention of the plunger and has a main body formed on a major diameter, a shank-latching portion formed on a minor diameter, and a transition section therebetween. The main body has a series of closed regular coils which partly thread onto the inverse spring thread of hammer barrel and in other part which, with inclusion of the transition section, generally project so that the shank-latching portion latches across the shank of the plunger just forward of the axial stop. That way, axial extensions of the spring normally retract the plunger back into the hammer barrel.

Abstract: A guide for removable attachment to a conventional pneumatic hammer adapts the hammer for use as a Pittsburgh lock hammer. The guide includes a hollow, open-ended tubular element which defines a fragmentary cylindrical wall, and an adjustable fastener is attached to the exterior surface of the wall for removably attaching the element to the pneumatic hammer.