Osg 4312300 Square End Mill 1-1/4 in 3 Flute Cobalt

Product Description

The OSG 4312300 is a single-end, square-profile end mill designed for general-purpose milling operations in ferrous and non-ferrous metals. Built from cobalt high-speed steel, it delivers improved heat and wear resistance compared to standard M2 HSS tooling. The cutter runs a 3-flute geometry with a 35-degree helix angle and a centercutting configuration, allowing both plunge and peripheral cuts. The 1-1/4 inch diameter cutting head seats on a matching 1-1/4 inch straight shank, making it compatible with standard collet chucks and end mill holders in that bore size. Installed by machinists and tool-room operators in CNC mills and manual knee mills.

The 4312300 is suited for slotting, profiling, and contouring operations where chip evacuation and surface finish matter. The coarse pitch flute spacing and 35-degree helix promote efficient chip flow in deeper cuts. The uncoated cobalt substrate works well in applications where regrinding is part of the shop workflow, as the tool can be resharpened without stripping a coating. Typical install environments include job shops, maintenance shops, and production floors running steel, stainless, and cast iron workpieces.

Key Features

• Cobalt HSS construction for elevated heat resistance versus standard HSS
• 3-flute, 35-degree helix geometry for efficient chip evacuation
• Centercutting design enables direct plunge entry into the workpiece
• Right-hand cut, right-hand flute configuration
• Uncoated finish suitable for shops that regrind tooling
• Coarse pitch spacing reduces chip packing in slotting operations

Compatibility

Designed for use with standard end mill holders and collet chucks sized for a 1-1/4 inch shank bore. Part of the OSG Series 430 square end mill line.

Installation Notes

Installation is performed by a qualified machinist or toolroom technician. Ensure the machine spindle is fully stopped and the tool holder is clean and free of chips before seating the shank. Verify runout with a dial indicator after clamping to confirm concentricity within the tolerance required by the operation. Follow the machine manufacturer and tooling manufacturer recommendations for speeds and feeds based on workpiece material and depth of cut.