Northfield Precision Instrument Corp. designs and manufactures of precision workholding chucks. When a good customer required a chuck to hold parts to be mounted to a Studer grinder for contour grinding into special cutting tools, it turned to Northfield for help. Northfield's engineers customized the Model 650 chuck to use only one jaw for clamping.

A special face mounted "V" block jaw was bolted to the chuck face and picks up the "V" locating surfaces of the special cutting tools. The bolt on the "V" is made of hardened tool steel, and is wire cut to finish size. Only one of the chuck's three jaws is used for clamping by driving the work piece into the fixed "V" locator. To insure the flat on the moving
jaw aligned perfectly with the flats of the tool, an insert was used that allowed the flat to rotate into position, insuring full contact.