Abstract: An apparatus for punching holes in thin sheet stock includes an improved clamping arrangement which holds the sheet stock firmly during the punching operation in the regions surrounding the hole to be cut as well as in the slug region which is to be cut from the sheet.

Abstract: A metal plate shears for cutting large sheets of metal includes a fixed blade, and a movable blade cooperable therewith. The movable blade is mounted on a plate having a plurality of circular apertures therein. Discs are mounted in these apertures, the discs being eccentrically supported, the axes of the eccentrics being in the same angular relation to and the same angular relation from, the centers of the discs. Arms are secured to the discs, and hydraulic means are provided for rotating the discs about their eccentric axes. Rotation of the discs lowers the plate bearing the movable cutting knife past the fixed knife, shearing off a sheet inserted between the blades.