5C step chuck collet closers from Lexair Inc. (www.LexairInc.com) are made with threaded noses and designed to accept standard 5C collets up to 0.6875-in. diameter, 5C step chucks up to 6-in. diameter and expanding 5C collets for I.D. holding.
The closers operate at up to 150 psi air pressure or 750 psi hydraulic pressure, and have a drawtube force of 7.5 times line pressure. This produces a theoretical clamping force of 1, 688 lb. on air and 8,438 lb. on hydraulic at maximum drawtube force.