Value Collection 231-4812 R8 Round Collet 12mm

Product Description

The VALUE COLLECTION 231-4812 is a 12mm R8 round collet machined from steel for use in milling machines and manual machining centers equipped with an R8 spindle taper. The collet accepts a 7/16-20 drawbar thread and holds a 12mm diameter cutting tool or workholding shank. Total indicator runout (TIR) is rated at 0.0007 inches, providing the concentricity required for accurate milling, drilling, and light boring operations. Installation requires a standard drawbar wrench and proper torque to seat the taper. This collet is suited for tool rooms, job shops, and maintenance machining environments.

R8 collets are the standard spindle tooling interface on Bridgeport-style vertical knee mills and many import-style benchtop and floor-standing milling machines. The 12mm bore size accommodates metric-shank end mills, drill blanks, and similar round-shank tooling. This collet is installed and serviced by machinists, tool-and-die technicians, and maintenance mechanics performing metal removal operations in both production and repair environments.

Key Features

• 12mm collet bore for metric-shank tooling
• R8 taper profile for compatibility with R8 spindle milling machines
• 0.0007 inch TIR rating for consistent concentricity
• 7/16-20 drawbar thread for secure spindle engagement
• Steel construction for durability under repeated clamping cycles

Compatibility

Designed as an OEM-style replacement or addition for milling machines equipped with an R8 spindle taper and a 7/16-20 drawbar thread.

Installation Notes

Installation and removal is performed by a qualified machinist or maintenance technician. Power down and lock out the milling machine before inserting or removing the collet. Use the correct drawbar wrench to tighten the 7/16-20 drawbar to proper engagement — do not over-tighten, as this can gall the taper or damage the spindle bore. Inspect the collet bore and spindle taper for chips or debris before seating.