Abstract: A workpiece locating unit is receivable in a T-slot formed in a workpiece supporting table member and provides a pin or other locating device cooperable with a locating feature on a workpiece to aid in accurately positioning the workpiece on the work supporting surface of the table member. The unit has four corners each providing an abutment surface for engagement with one or the other of two vertical slot surfaces. Two diagonally opposite ones of the abutment surfaces are rigid and the other two diagonally opposite ones of the abutment surfaces are resilient. The resilient abutment surfaces resiliently engage the two vertical surfaces of the slot and urge the unit about a vertical axis to hold the rigid abutment surfaces engaged with the vertical slot surfaces eliminating lateral looseness between the unit and the table member and providing accurate positioning of the locating device of the unit as the unit is moved from one position to another along the length of the slot.