Osg 5320400 Square End Mill 5/16 in 3 Flute Cobalt

Product Description

The OSG 5320400 is a cobalt square end mill designed for metal cutting in milling operations across manufacturing and machining environments. Built from M42 cobalt high-speed steel, this double-end tool delivers heat and wear resistance suited to difficult-to-machine steels and alloys. The 5/16-inch cutting diameter is paired with a 3/4-inch length of cut and a 30-degree helix angle that promotes smooth chip evacuation and reduced cutting forces. With three flutes and a spiral flute geometry, it balances material removal rate with surface finish quality. This tool is installed and used by machinists and tool-and-die professionals in CNC and manual milling applications.

The OSG 5320400 fits standard milling setups where a 3/8-inch shank diameter is required. Its 3-1/2-inch overall length suits typical knee mill, vertical machining center, and bridgeport-style machine tool holders. The centercutting design allows plunge cuts as well as conventional side milling and slot milling. The right-hand cut, right-hand flute configuration is the standard orientation for most vertical milling operations. The double-end design extends tool life by providing a second usable cutting end.

Key Features

• M42 cobalt HSS construction for heat resistance in ferrous and difficult-to-machine materials
• Double-end design provides two usable cutting ends per tool
• Centercutting capability allows plunge milling without a pre-drilled entry hole
• 30-degree helix angle promotes efficient chip evacuation and smooth cutting action
• Three-flute geometry balances chip load and surface finish in slotting and profiling
• Uncoated finish — suitable for regrinding and application-specific coating if required

Compatibility

Designed for use in milling machines accepting a 3/8-inch shank diameter. Part of the OSG Series 532 double-end cobalt square end mill line.

Installation Notes

Install this end mill in a collet chuck or end mill holder rated for the 3/8-inch shank diameter, ensuring the holder is clean and free of debris before seating the tool. Power down the machine spindle completely before changing tooling, and verify runout with a dial indicator after installation to confirm proper seating. Follow the machine manufacturer and OSG cutting data recommendations for speed and feed parameters based on workpiece material. Secure the workpiece firmly before beginning any cut.