Accupro 771257 CAT40 Milling Chuck 1-1/4 Inch Hole

Product Description

The ACCUPRO 771257 is a CAT40 milling chuck designed for use in CNC machining centers requiring secure, high-precision tool holding. It features a dual contact taper shank that engages both the spindle taper and the spindle face simultaneously, improving rigidity and reducing runout compared to standard single-contact toolholders. The chuck accepts a 1.25-inch hole diameter and delivers a TIR of 0.0002 inches, making it suitable for milling applications where concentricity and repeatability are critical. Through-spindle coolant capability directs cutting fluid directly to the tool tip for improved chip evacuation and thermal management in demanding cutting conditions. This toolholder is installed by CNC machinists and toolroom technicians in production and job shop environments.

This chuck is suited for use in CAT40-spindle vertical and horizontal machining centers running face mills, shell mills, and other large-diameter milling cutters with a 1.25-inch arbor bore. The 3.54-inch projection and 6.22-inch overall length accommodate standard setups where moderate gage length is required. The 2.88-inch nose diameter provides a stable clamping platform for heavy interrupted cuts and high-feed milling operations. It is a practical choice for production environments running steel, aluminum, and cast iron where consistent tool positioning and coolant delivery are required across repeated setups.

Key Features

• Dual contact taper shank engages spindle taper and face for increased rigidity and reduced vibration
• TIR of 0.0002 inches supports precision milling with tight tolerances
• Through-spindle coolant delivers cutting fluid directly to the cutting zone
• 1.25-inch hole diameter accommodates standard large-bore milling arbors
• 3.54-inch projection and 6.22-inch overall length suit standard machining center setups
• CAT40 taper is one of the most widely used toolholder standards in North American CNC machining

Compatibility

Designed for use in CAT40-spindle CNC machining centers equipped with through-spindle coolant and dual contact spindle interface. Compatible with milling arbors and shell mill adapters with a 1.25-inch bore.

Installation Notes

Installation should be performed by a qualified CNC machinist or toolroom technician. Always power down and lock out the machining center spindle before mounting or removing toolholders. Clean the spindle taper and toolholder shank thoroughly before seating to ensure full dual contact engagement and accurate TIR. Follow the machine tool builder torque specifications for the retention knob and drawbar; use only the correct pull stud style specified for the machine spindle.