Northfield Precision Instrument Corp. introduces its internal grip collet chuck. This collet chuck was custom-designed for a customer to clamp the ID of valve balls. The collet is a dead-length collet with a removable split part stop (part stop is made into two pieces and is hinged) to locate the back of the workpiece and is removed after clamping the workpiece and prior to grinding of the workpiece.

This chuck is used in a valve ball grinder. The ball is approximately 6" in diameter. The customer needed to locate and stop the ball axially on the chuck. So Northfield provided a removable spacer (locator/stop) behind the ball (between the ball and chuck) for axial location. The Locator needed to be removable to allow the grinding wheel (cup) access around the top and bottom of the ball.