Value Collection 231-4742 R8 Collet 21/32 Inch Steel

Product Description

The VALUE COLLECTION 231-4742 is a steel R8 collet designed for use in milling machines and machining centers equipped with an R8 spindle taper. This collet accepts a 21/32 inch tool shank and uses a 7/16-20 drawbar thread for secure retention during operation. It holds a total indicated runout (TIR) of 0.0007 inches, supporting accurate, repeatable tool positioning across a range of machining tasks. The steel construction provides durability under the cutting forces and vibration common in production and job-shop environments. Machinists, tool-and-die makers, and CNC operators are the typical end users.

This R8 collet is suited for manual Bridgeport-style knee mills and similar vertical milling machines that use the R8 spindle standard. It is used when mounting end mills, drill bits, reamers, or other round-shank cutting tools with a 21/32 inch diameter. The application spans general metalworking, toolroom work, and light production machining in both shop and industrial settings.

Key Features

• 21/32 inch bore accommodates standard round-shank cutting tools
• R8 taper profile for direct spindle fit on compatible milling machines
• 7/16-20 drawbar thread for secure axial clamping
• 0.0007 inch TIR for accurate tool centerline positioning
• Steel construction for strength and wear resistance under machining loads

Compatibility

Designed as an OEM-style replacement or direct-fit collet for milling machines using the R8 spindle taper standard with a 7/16-20 drawbar thread.

Installation Notes

R8 collets are installed and removed by a qualified machinist with the machine powered down and the spindle at rest. The collet is inserted into the spindle taper and secured by threading the drawbar down through the spindle head by hand, then snugging with a wrench — do not overtighten the drawbar, as this can damage the collet or spindle. Always clean the spindle bore and collet taper surfaces before installation to prevent runout caused by debris. Follow the machine manufacturer's drawbar torque guidelines when specified.