An apparatus for producing perforated pounce patterns from sheet material has a work-engaging surface for moving and supporting the sheet material. A tool carriage is supported adjacent, and movable relative to the work-engaging surface, and a tool mount is supported on the tool carriage and movable between elevated and lowered positions relative to the work-engaging surface. A pouncing tool is supported in the tool mount and has a tool shaft and a pouncing wheel rotatably suspended from the tool shaft. The pouncing wheel has a plurality of radially extending pins for forming a perforated path in the shape of a pounce pattern when engaged with the sheet material on the work-engaging surface. A keying member is engaged with the tool mount, and the tool shaft has a longitudinally extending keyway engageable with the keying member for fixing the orientation of the pouncing tool relative to the tool mount. A controller during movement of the pouncing tool relative to the sheet material along a line to be perforated rotates the tool mount so that the pouncing wheel axis of rotation is maintained at an oblique angle to the line of tangency between the wheel and the perforated line thereby producing improved perforations in the sheet material that do not tend to close after being formed.