Abstract: A workpiece holding system includes a connector for mounting a workpiece-holding pallet or upper plate to a workstation with the high degree of accuracy that is necessary for workpiece machining operations. The upper plate connects to the workstation via a pair oppositely directed, extendable/retractable connectors aligned along an axis of connection, with a total of four connectors and two spaced axes of connection, though three such connectors may also be used. At least one of the connectors includes a pin, an actuating knob and a wrap spring, thereby to permit extension and retraction along the respective axis by rotation of the actuating knob. The wrap spring interconnects the actuating knob to the pin in a slippable manner. The wrap spring acts as a torque limiting device during rotation of the knob to extend the pin into engagement with the upper plate, and it acts as a clutch during rotation of the knob to retract the pin from engagement with the pallet.

Abstract: A versatile set up assembly for holding a workpiece during a machining operation includes upper and lower plates that can be selectively hingedly connected and/or disconnected along spaced parallel axes of connection, thereby permitting either end of the upper plate to be hingedly raised with respect to the lower plate, or the upper plate removed entirely. Two rolls are rotatably mounted to one of the plates along two spaced, parallel axes. The other plate has two pairs of connectors, each pair axially aligned with and adapted to precisely engage the outer ends of one off the rolls along an axis of connection. When the aligned connectors are moved into engagement with the respective ends of a roll, precisely machined surfaces of the connectors and the outer ends coact to ensure the forming of an accurate and repeatable hingable connection between the plates along the axis of connection.