Osg 5205400 Square End Mill 1-3/8 in 2 Flute Cobalt

Product Description

The OSG 5205400 is a cobalt square end mill designed for milling operations requiring durability and heat resistance beyond standard high-speed steel tooling. Built to Series 520 specifications, it features a 1.375-inch cutting diameter, a 1.625-inch length of cut, and a 2-flute spiral configuration with a 30-degree helix angle. The cobalt construction — material grade M42 — provides elevated red hardness, making it suitable for cutting tougher ferrous and non-ferrous materials. This is a single-end, centercutting tool with a right-hand cut and right-hand flute direction, intended for use by machinists and tool-and-die professionals on CNC machining centers and manual mills.

This end mill is suited for face milling, slotting, and peripheral milling in production and job-shop environments. The 2-flute design promotes chip evacuation in deeper cuts and softer materials where chip load per tooth needs to stay manageable. The 1-inch shank diameter and 4.125-inch overall length place it in the regular-length category, appropriate for standard reach applications where extended reach tooling is not required. It is an uncoated tool, which keeps regrinding straightforward and makes it compatible with grinding operations that would otherwise require coating removal.

Key Features

• M42 cobalt construction for elevated heat resistance and tool life on harder work materials
• Centercutting geometry allows direct plunge entry into the workpiece
• 30-degree helix angle balances cutting efficiency with lateral cutting force
• Spiral flute design promotes consistent chip flow and surface finish
• 2-flute configuration supports higher chip loads per tooth and better chip clearance in soft or gummy materials
• Uncoated finish simplifies regrinding and reconditioning

Compatibility

Designed as an OEM-style solid carbide-class replacement-style end mill for use in standard R8, CAT, BT, or direct-shank toolholders accepting a 1-inch shank diameter.

Installation Notes

Installation should be performed by a qualified machinist following shop safety protocols. Secure the 1-inch shank in a collet or end mill holder rated for the intended spindle speed and torque. Confirm runout with a dial indicator before beginning a cut, as excessive runout accelerates tool wear and degrades surface finish. Always power down and lock out the spindle before changing or adjusting tooling.