Value Collection 231-4716 R8 Round Collet 1/4 Inch

Product Description

The VALUE COLLECTION 231-4716 is a 1/4-inch R8 round collet machined from steel for use in Bridgeport-style vertical milling machines and other mills equipped with an R8 spindle taper. The collet accepts a 1/4-inch tool shank and uses a standard 7/16-20 drawbar thread for secure engagement with the machine spindle. A total indicated runout (TIR) rating of 0.0007 inches supports accurate, repeatable cuts across a range of milling operations. The part is suited for use by machinists, tool-and-die makers, and general machine shop personnel.

This collet is designed for standard vertical knee mills and similar machine tools fitted with an R8 spindle. It is appropriate for holding 1/4-inch shank end mills, drill bits, reamers, and other cutting tools of the same shank diameter. The 7/16-20 drawbar thread matches the standard R8 drawbar specification found on most domestic and imported R8-spindle machines. Typical applications include production milling, prototype work, and maintenance machining in both job shop and manufacturing environments.

Key Features

• 1/4-inch bore accepts standard 1/4-inch shank cutting tools
• R8 taper profile fits Bridgeport-style and compatible vertical milling machine spindles
• 7/16-20 drawbar thread matches standard R8 drawbar specification
• 0.0007-inch TIR for consistent tool concentricity and cut accuracy
• Steel construction for durability under repeated clamping cycles

Compatibility

Designed as a direct-fit replacement or supplemental collet for vertical milling machines equipped with an R8 spindle taper and a 7/16-20 drawbar thread.

Installation Notes

Installation is performed by a qualified machinist or machine tool operator. Power down and de-energize the machine before changing collets. Insert the collet into the spindle bore and thread the drawbar by hand before snugging with a wrench — do not overtighten the drawbar, as this can damage the collet or spindle. Inspect the collet bore and spindle taper for chips or debris before each use to maintain TIR performance.