Autolock collets require cutters with threaded shank ends to screw into the collet itself. Unlike most other machine collet systems, 5C collets were developed primarily for work holding. Watch collets also include taper adapters and wax or cement chucks. They are also used for machining arbors, cams, chucks, and collets. Watchmakers lathes all take collets which are sized by their external thread. Suitable collets may also be used to mount square or hexagonal workpieces. R8 collets were developed by Bridgeport Machines, Inc. for use in milling machines. These, like "Straight" rod holding collets close onn the outer taper. Reusable separation collets and a pneumatic pusher system separate the stages. Reusable separation collets and a pneumatic pusher system separates the stages. Stage separation occurs via reusable separation collets and a pneumatic pusher system. Separation collets and a pneumatic pusher system separate the stages. The original fittings had brass collets and zinc or brass bodies. The penalty is that most collets can only accommodate a single size of workpiece. These collets can be obtained in steel, brass, or nylon.