Accupro 775341 End Mill Holder R8 Taper Shank

Product Description

The ACCUPRO 775341 is an R8 taper shank end mill holder designed for use in milling machines equipped with R8 spindles. It accepts end mills with a 3/16 inch shank diameter and provides a projection of 1.33 inches from the gauge line to the tool-holding face. The holder achieves a Total Indicator Reading (TIR) of 0.0002 inches, supporting accurate tool runout control during milling operations. It does not support through-coolant delivery. The drawbar thread is sized at 7/16-20 UNF, matching the standard drawbar specification common to Bridgeport-style and comparable R8-spindle machines. Licensed machinists and tool room technicians are the primary installers.

This end mill holder suits vertical knee mills, bed mills, and other manual or CNC milling machines with R8 spindle tapers. It is well suited for light to medium milling work in job shops, maintenance departments, and production environments where a secure, repeatable tool seat is required. The 3/16 inch bore accommodates smaller diameter end mills and cutting tools used for fine detail work, slotting, and profile milling on ferrous and non-ferrous materials.

Key Features

• R8 taper shank for direct fit in R8-spindle milling machines
• 3/16 inch bore diameter for small-shank end mills and cutting tools
• 1.33 inch projection from gauge line to tool face
• TIR of 0.0002 inches for controlled tool runout
• 7/16-20 UNF drawbar thread matches standard R8 machine drawbar
• No through-coolant, simplifying setup in dry or flood-coolant environments

Compatibility

Designed as an OEM-style replacement and standard tooling holder for milling machines fitted with R8 taper spindles and a 7/16-20 UNF drawbar thread.

Installation Notes

Installation is performed by a qualified machinist or toolroom technician. Power down and lock out the machine spindle before inserting or removing the holder. Seat the R8 taper fully into the spindle bore and tighten the drawbar to the machine manufacturer's recommended torque specification before initiating any cut. Inspect the taper and bore for chips or contamination prior to each use to maintain TIR performance.