Hertel E299921163 Square End Mill 21/64 in 4 Flute Cobalt

Product Description

The HERTEL E299921163 is a single-end, square-profile cobalt end mill designed for milling operations in ferrous and tough alloy materials. Built from M42 cobalt high-speed steel, it delivers heat and wear resistance that standard HSS tooling cannot match. The cutter measures 21/64 inches (0.3281 inches) in diameter with a 3/4 inch length of cut and a 30-degree right-hand spiral helix. It runs four flutes in a right-hand cutting direction, producing efficient chip evacuation on profile milling, slotting, and peripheral cuts. This tool ships in a bright, uncoated finish. It is installed and used by machinists and tool-and-die professionals on manual mills and CNC machining centers.

This end mill is suited for shops working with alloy steels, stainless steels, and other materials that generate significant cutting heat. The 3/8 inch shank diameter fits standard collet chucks and end mill holders common to both knee mills and CNC vertical machining centers. With a 2-1/2 inch overall length and no extended-reach geometry, it is a compact, rigid setup appropriate for general-purpose cavity work, step milling, and contour passes in a production or toolroom environment.

Key Features

• M42 cobalt HSS construction for elevated heat resistance and tool life in tough alloys
• 4-flute, right-hand spiral configuration for efficient chip removal and surface finish
• 30-degree helix angle balances cutting force and chip flow across a range of feed rates
• Center-cutting geometry allows direct plunge entry without a pre-drilled pilot hole
• Bright/uncoated finish for compatibility with a wide range of cutting fluids and materials
• Single-end design with 3/8 inch shank for rigid clamping in standard toolholders

Compatibility

Designed as an OEM-style replacement or standard toolroom end mill fitting any machine spindle that accepts a 3/8 inch shank via collet, set-screw holder, or shrink-fit toolholder.

Installation Notes

Installation is performed by machinists following standard toolroom practice. Ensure the machine spindle is fully stopped and locked before inserting or removing the cutter from the toolholder. Verify runout with a dial indicator after clamping and before cutting. Follow your machine tool manufacturer and shop safety guidelines for speeds, feeds, and coolant application when working with cobalt HSS tooling.