Accupro 771028 CAT40 End Mill Holder 1/2 Inch Bore

Product Description

The ACCUPRO 771028 is a CAT40 dual contact taper shank end mill holder designed for use in CNC machining centers requiring high-speed, high-precision toolholding. The dual contact interface engages both the taper and the spindle face simultaneously, improving rigidity and reducing runout compared to standard single-contact holders. The holder accepts a 1/2 inch bore end mill, features a 4 inch projection, and is balanced to 30,000 RPM. Through-coolant capability supports both through-spindle and DIN flange coolant delivery. Runout (TIR) is held to 0.0002 inches, making this holder suitable for finish milling and tight-tolerance work. A licensed machinist or CNC toolroom technician is the typical installer.

This holder is suited for horizontal and vertical CNC machining centers equipped with a CAT40 spindle. The 4 inch projection provides clearance for deep-cavity or obstructed workpiece features. The 1-3/8 inch nose diameter and 1-1/2 inch clamping depth accommodate standard end mill shank lengths. Through-coolant support makes this holder a practical choice for high-feed operations, hardened materials, or applications where chip evacuation and tool life are critical factors. The 5/8-11 retention knob thread is standard for CAT40 tooling systems.

Key Features

• CAT40 dual contact taper shank for increased spindle rigidity and face contact
• 1/2 inch bore with 1-1/2 inch clamping depth for secure end mill retention
• 4 inch projection for clearance on deep-cavity or complex workpieces
• Balanced to 30,000 RPM for high-speed machining applications
• Through-coolant compatible via through-spindle and DIN flange delivery
• TIR of 0.0002 inches for tight-tolerance and finish milling work

Compatibility

Designed as an OEM-style replacement or direct-fit toolholder for CAT40 spindle machining centers using a 5/8-11 retention knob thread.

Installation Notes

Installation should be performed by a qualified CNC toolroom technician or machinist. Power down and lock out the machining center spindle before installing or removing the holder. Use a calibrated torque wrench and the appropriate pull stud when seating the retention knob. Verify runout with a dial test indicator after tool assembly and before running the spindle at speed.