Osg 5312500 Square End Mill 7/8 in 3 Flute Cobalt

Product Description

The OSG 5312500 is a cobalt square end mill designed for milling ferrous and difficult-to-machine materials in metalworking and machining applications. Built from M42 cobalt high-speed steel, it offers higher heat and wear resistance than standard HSS, making it well suited for harder steels and stainless alloys. The cutter measures 0.875 inches in diameter with a 1.875-inch length of cut and a 0.625-inch shank diameter. Overall length is 4.0 inches. The 3-flute, 30-degree spiral helix geometry balances chip evacuation with surface finish quality. This end mill ships uncoated and is ready to run in standard machining centers, knee mills, and manual mills.

This end mill is used in job shop, toolroom, and production machining environments for slotting, profiling, and shoulder milling operations. The regular-length geometry and 5/8-inch shank make it compatible with standard ER collets, end mill holders, and Weldon-style holders found in most milling setups. It is a right-hand cut, right-hand flute configuration, which is the standard orientation for conventional and climb milling on vertical and horizontal machining centers.

Key Features

• M42 cobalt construction for improved heat resistance and tool life in harder materials
• 3-flute, 30-degree helix spiral flute for balanced chip evacuation and finish quality
• Centercutting design allows plunge and ramp entry cuts
• Right-hand cut, right-hand flute — standard orientation for most milling setups
• Uncoated finish suitable for use with cutting fluids on a wide range of materials
• Regular length geometry for rigidity in general milling applications

Compatibility

Designed as a direct-fit replacement or standard tooling selection for 5/8-inch end mill holders, ER collet chucks, and Weldon-style holders used in vertical and horizontal milling machines. Part of the OSG Series 531 cobalt end mill line.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Ensure the machine spindle is fully stopped and locked out before changing tooling. Seat the shank fully into the holder to the recommended grip depth and torque set screws or collet nuts per the holder manufacturer specifications. Verify runout with a dial indicator before beginning the cut, as excessive runout accelerates tool wear and reduces surface finish quality.