Value Collection 231-4728 R8 Collet 7/16 Inch Steel

Product Description

The VALUE COLLECTION 231-4728 is a 7/16 inch R8 collet machined from steel for use in Bridgeport-style vertical milling machines and compatible spindles. It accepts a 7/16-20 drawbar thread and holds tooling at a 7/16 inch shank diameter. The collet is rated at 0.0007 inch total indicator runout (TIR), providing the concentricity control required for accurate milling operations. This type of collet is installed and serviced by machinists and tool-room professionals working on knee mills, bed mills, and similar manual or CNC-compatible R8-spindle equipment.

R8 collets are the standard toolholding interface for Bridgeport and Bridgeport-style knee mills widely used in job shops, maintenance facilities, and vocational training environments. This collet is suited for holding 7/16 inch shank end mills, drill bits, reamers, and other straight-shank cutting tools. It is appropriate for both roughing and finishing passes where consistent tool runout matters. Each package contains one collet.

Key Features

• 7/16 inch bore diameter for straight-shank tooling
• R8 taper profile fits Bridgeport-style spindles
• 7/16-20 drawbar thread for secure spindle engagement
• 0.0007 inch TIR for reliable concentricity in milling applications
• Steel construction for durability under milling loads

Compatibility

Designed as an OEM-style replacement R8 collet for Bridgeport-style vertical knee mills and other manual or CNC milling machines equipped with an R8 spindle taper and a 7/16-20 drawbar thread.

Installation Notes

R8 collets are installed and removed by a qualified machinist. Power down and lock out the machine spindle before changing collets. Clean the spindle bore and collet taper of chips and oil before seating the collet to maintain TIR accuracy. Tighten the drawbar to the mill manufacturer's recommended procedure using an appropriate wrench — do not overtighten, as this can damage the collet or spindle bore.