Value Collection 231-4748 R8 Round Collet 3/4 Inch

Product Description

The VALUE COLLECTION 231-4748 is a 3/4-inch R8 round collet machined from steel for use in milling machines equipped with an R8 spindle taper. It features a 7/16-20 drawbar thread and a total indicator runout (TIR) of 0.0007 inches, making it suitable for precision workholding in production and job-shop environments. The R8 collet style is one of the most widely used standards in vertical milling machines, and this collet accepts round shank tooling at the 3/4-inch nominal diameter. Machinists and tool-and-die technicians install this collet directly into the spindle and secure it via the drawbar.

This collet is intended for use in vertical knee mills and similar machines built around the R8 spindle standard. It is a standard round collet designed to hold straight-shank end mills, drill blanks, and other cylindrical tooling with a 3/4-inch shank diameter. It is commonly found in job shops, maintenance facilities, and educational machine shops where R8-spindle equipment is standard. The low TIR value of 0.0007 inches supports repeatable, accurate tool engagement during cutting operations.

Key Features

• 3/4-inch nominal bore accepts straight-shank round tooling
• R8 taper profile fits R8-spindle milling machines
• 7/16-20 drawbar thread for secure spindle engagement
• 0.0007-inch TIR for precision workholding accuracy
• Steel construction for durability under repeated clamping cycles

Compatibility

Designed as an OEM-style replacement or standard addition for vertical milling machines with an R8 spindle taper accepting 3/4-inch round shank tooling and a 7/16-20 drawbar thread.

Installation Notes

Installation is performed by a machinist or qualified tool-room technician. Before inserting or removing the collet, ensure the machine spindle is fully stopped and the power is locked out per OSHA lockout/tagout procedures. Insert the collet into the R8 spindle bore, engage the drawbar thread, and tighten the drawbar with a wrench while holding the spindle brake — do not over-torque. Inspect the collet bore and spindle taper for chips or debris before each use to maintain runout accuracy.