Abstract: Mounted upon the lower jaws of a gripping and manipulating tool is an obtuse-angled adapter plate to which is secured an adjustable work positioner including a stationary work-positioning V-block and a relatively movable work-positioning block provided with a work-holding recess consisting of a notch shaped to fit the edge of the workpiece to be contour ground. The stationary V-block contains a right-angled recess which is shaped to fit and become coaxially centered with respect to a centering portion of rectangular cross-section coaxial with the work-holding spindle of the contour work-turning machine such as a contour grinder. A fastener is provided for clamping the adjustable block to the stationary block and passes through a vertical slot in the adjustable block into a threaded bore in the stationary block.