Abstract: A punch press having a bed, a reciprocable press ram carrying a die member, means for reciprocating the ram between raised and lowered positions, and a sliding bolster plate carrying another die member mounted for movement between a withdrawn load position and a retracted work position. The press includes a drive assembly for harmonically reciprocating the bolster plate, positioning sensors for disconnecting the drive assembly when the bolster plate reaches its load position or its work position, a positioning control mechanism for locking the bolster plate at its work position and triggering reciprocation of the press ram and an electrical operating and interlock circuit for controlling and ensuring proper operation of the press.