Abstract: A fastener forming apparatus comprises a positive stop that prevents workpieces from overshooting the end of a forming stroke. A workpiece transfer mechanism transfers one unformed workpiece at a time into a workpiece gripper and drives completed workpieces out of the workpiece gripper and onto an exit path. A compound hydro-pneumatic cylinder moves the gripper and one workpiece at a time downward into contact with a rotating forming tool. A knurled ring is adjustably supported on a threaded portion of a lower piston of the hydro-pneumatic cylinder in a position to contact a stationary stop surface when the workpiece gripper and tool reach the end of the forming stroke, halting the downward motion of the workpiece. The ring also actuates a lower limit switch at the stationary stop surface which causes the reciprocator to reverse direction. The forming tool includes a tool adapter head that holds various forming implements such as cutting blades or drill bits.