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Clamping System with Quick-Change Collets

RÖHM Products of America has introduced its modular CAPTIS workpiece clamping system with quick change collets. The system provides a wide range of workholding options for turning, milling and drilling applications through different combinations of modular components, while shortening set-up times through fast and easy operation.

CAPTIS features an innovative quick-change capability that permits conversion from external to internal clamping in less than a minute. The system produces strong clamping forces without deformation of delicate workpieces while offering high repeatability and minimal run out. CAPTIS is compatible with the industry standard BZI collet interface.

Different configurations of the CAPTIS system deliver a variety of workholding functions, including:

  • The power-operated, rotating CAPTIS collet chuck is designed for use in turning machines. Its compact size facilitates full use of a machine's work envelope.
  • CAPTIS-D is equipped with axial tightening for machining bar stock and can be easily converted to the CAPTIS-A, which is ideal for flange-type workpieces and includes workpiece stop and hold-down features.
  • CAPTIS-AF, with an axially fixed (dead-length) collet and optional workpiece stop, is ideally suited for delicate workpieces, short clamping surfaces and use in counter spindles.
  • The stationary CAPTIS-MS collet chuck is intended for use in drilling, milling and machining centers and for manual machining. Operated manually with hydraulic power intensification, the chuck can be optionally equipped with a front or internal stop.

To further enhance productivity, the CAPTIS system uses ROHM's line of quick-change collet chucks that enables collet changes to be made in 15 seconds. Each collet consists of three segments separated by rubber joints. Holes in the collet align with pins on a pistol-grip changing fixture.

Users squeeze the fixture's trigger, and the action compresses the rubber joints and enables the collet to fit quickly and easily into the collet chuck to reduce set-up times. When the fixture releases the collet, it expands to lock securely into the chuck. "Unlike traditional spring grip collets, the quick change collets provide grip along their entire length and ultra-precision accuracy of 0.0002 in. TIR or better," said a company spokesperson.

RÖHM provides the industry standard collets in smooth and serrated bore styles, in versions to accommodate inch sizes from 0.218" to 1.625" (in 0.062" increments) and 0.250" to 2.562" (in 0.062" increments). Metric, hex and square sizes are quoted upon request. RÖHM collets are available at

For more information contact:

RÖHM Products of America

2500 Northlake Drive

Suwanee, GA 30024


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