Accupro 771220 Shell Mill Holder CAT50 1 Inch Pilot

Product Description

The ACCUPRO 771220 is a CAT50 dual contact taper shank shell mill holder designed for secure, high-precision face milling operations on CNC machining centers. The dual contact interface engages both the taper and the spindle face simultaneously, increasing rigidity and reducing runout compared to standard taper-only holders. Total indicator runout (TIR) is rated at 0.0002 inches. The holder features a 1-inch pilot diameter, a 2.75-inch nose diameter, and a flange-to-nose projection of 6 inches, with an overall length of 10 inches. Through-spindle and DIN flange coolant delivery are both supported. This holder is installed by CNC machinists and tooling specialists in production shop environments.

The 771220 is suited for face milling and shell milling applications on vertical and horizontal CNC machining centers equipped with CAT50 spindles. It accepts shell mill cutters in the 2.25-inch to 2.75-inch cutting diameter range. The through-coolant capability supports flood and directed coolant strategies used in steel, cast iron, and aluminum milling. The lock screw thread size is 1/2-20. Balanced to 10,000 RPM, this holder is appropriate for both roughing and finishing operations where spindle stability and minimal runout are critical.

Key Features

• Dual contact taper shank engages both taper and spindle face for increased rigidity
• TIR rated at 0.0002 inches for high-precision fitment
• Through-spindle and DIN flange coolant delivery supported
• Balanced to 10,000 RPM for stable high-speed milling
• Accepts shell mill cutters from 2.25 inches to 2.75 inches cutting diameter
• Lock screw thread size 1/2-20 for secure cutter retention

Compatibility

Designed for use with CAT50 spindle machining centers accepting dual contact taper shank toolholders. Compatible with shell mill cutters in the 2.25-inch to 2.75-inch cutting diameter range.

Installation Notes

Installation should be performed by a qualified CNC machinist or tooling technician with the machine powered down and the spindle locked before mounting or removing the holder. Ensure the spindle taper and holder shank are clean and free of chips, burrs, or coolant residue before seating to achieve proper dual contact engagement. Verify draw bar torque per the machine tool manufacturer specification before resuming operation. Coolant port connections should be confirmed leak-free before running through-spindle coolant.