Robbjack ACH-08 End Mill Holder 5/8 in Weldon Flat

Product Description

The ROBBJACK ACH-08 is a Weldon flat straight shank end mill holder designed for secure tool retention in CNC machining centers and manual milling machines. It accepts a 1/4 inch bore and features a 5/8 inch shank diameter with a through-coolant channel that delivers cutting fluid directly to the tool tip. With an overall length of 4.25 inches, this holder provides the reach and rigidity needed for general-purpose milling operations. Machinists and CNC setup technicians install this holder when running end mills that require high clamping force and precise concentricity.

This end mill holder suits production and job-shop environments where through-coolant capability is required for extended tool life and chip evacuation. The Weldon flat drive design provides positive engagement between the set screw and the tool shank, reducing pull-out risk under aggressive cutting conditions. Typical applications include ferrous and non-ferrous milling in vertical machining centers. Weighing 0.25 pounds, it is a compact, lightweight holder suited to smaller-diameter tooling setups.

Key Features

• Through-coolant channel directs fluid to the cutting zone for improved tool life and chip removal
• Weldon flat straight shank design provides positive set-screw engagement to resist tool pull-out
• 5/8 inch shank diameter for use in standard milling machine spindles accepting that bore size
• 1/4 inch tool bore accommodates standard 1/4 inch shank end mills
• 4.25 inch overall length offers reach for a range of workpiece configurations
• Lightweight at 0.25 pounds, minimizing added spindle load

Compatibility

Designed as an OEM-style end mill holder for milling machines and CNC machining centers that accept a 5/8 inch straight shank tool holder with Weldon flat drive and a 1/4 inch tool bore.

Installation Notes

Installation should be performed by a qualified machinist or CNC setup technician with the spindle fully powered down and locked out per the machine tool manufacturer's lockout/tagout procedure. Insert the end mill shank fully into the bore before tightening the set screw against the Weldon flat. Verify through-coolant port alignment with the machine spindle coolant passage before final assembly. Inspect the bore and shank for burrs or contamination prior to assembly to maintain concentricity.