Osg 5220405 Square End Mill 5/16 in 2 Flute Cobalt

Product Description

The OSG 5220405 is a cobalt square end mill designed for general-purpose milling in ferrous and hard materials where high-speed steel alone falls short. Built to Series 522 standards, this double-end tool features a 5/16-inch cutting diameter, a 9/16-inch length of cut, and a 3/8-inch shank diameter with an overall length of 3-1/8 inches. The 30-degree spiral flute geometry promotes efficient chip evacuation while the titanium nitride (TiN) finish increases surface hardness and reduces friction at the cutting edge. Two right-hand flutes with right-hand cut geometry make this tool suitable for standard milling center applications. Centercutting capability allows direct plunge entry without a pre-drilled pilot hole.

This end mill is used in manual mills, CNC machining centers, and knee mills for slotting, profiling, and plunging operations. The cobalt M42 substrate handles elevated cutting temperatures better than standard M2 HSS, making it a practical choice when machining alloy steels, stainless steels, and tough work materials at moderate speeds. The double-end configuration extends tool life by providing a second usable cutting end before the tool is retired. Typical applications include job shops, maintenance machining, and production environments where tool cost per edge is a consideration.

Key Features

• 5/16-inch cutting diameter with 9/16-inch length of cut for precise slot and profile work
• Cobalt M42 material grade for improved heat and wear resistance over standard HSS
• TiN coating reduces friction and extends cutting edge life
• 30-degree helix angle with spiral flute for effective chip evacuation
• Centercutting design enables direct plunge milling without a pilot hole
• Double-end construction provides two usable cutting ends per tool

Compatibility

Designed as an OSG Series 522 replacement or direct-use end mill compatible with standard 3/8-inch collet or end mill holder setups on vertical milling machines and CNC machining centers.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Secure the 3/8-inch shank in a clean, properly sized collet or end mill holder and torque to the machine tool manufacturer's specification. Inspect the collet and holder for runout before use, as excessive runout accelerates edge wear on small-diameter tooling. Always power down and lock out the spindle before changing tooling.