Osg 5420400 Square End Mill 5/16 in 4 Flute Cobalt

Product Description

The OSG 5420400 is a cobalt square end mill designed for milling, slotting, and profiling operations on ferrous and non-ferrous materials. Built from M42 cobalt high-speed steel, it delivers heat resistance and edge retention in demanding cutting conditions. The tool features a 5/16 inch cutting diameter, a 3/4 inch length of cut, and a 30-degree right-hand spiral flute geometry that promotes efficient chip evacuation. With four flutes and a right-hand cut, it is suited for finish and semi-finish passes on steel, stainless steel, and cast iron. Machinists and tool-and-die professionals install this end mill in conventional milling machines, CNC machining centers, and knee mills.

This end mill is configured as a double-end tool, meaning both ends are usable cutting edges, extending tool life and reducing per-cut cost. The 3/8 inch shank diameter fits standard ER collets and end mill holders common across most vertical machining setups. It falls within OSG Series 542, a regular-length cobalt end mill line intended for general-purpose shop use. The uncoated finish makes it appropriate for applications where coating compatibility or regrinding is a consideration. Typical applications include shoulder milling, slot milling, and peripheral profiling on workpieces requiring moderate tolerances.

Key Features

• M42 cobalt construction for elevated heat resistance compared to standard M2 HSS
• 30-degree helix angle promotes smooth chip flow and reduced cutting forces
• Four-flute configuration balances feed rate capacity with surface finish quality
• Double-end design provides two usable cutting ends per tool
• Uncoated finish supports easy regrinding and broad material compatibility
• Right-hand cut and right-hand flute geometry for standard spindle rotation

Compatibility

Designed as an OEM-style replacement or direct fitment end mill for standard 3/8 inch end mill holders and ER collet chucks used in vertical mills and CNC machining centers. Part of the OSG Series 542 regular-length cobalt end mill line.

Installation Notes

Installation should be performed by a qualified machinist following shop-standard tool-change procedures. Ensure the spindle is fully stopped and the machine is in an e-stop or locked-out state before changing tooling. Seat the shank fully in the collet or holder and torque the retention nut to the tool holder manufacturer's specification. Verify runout with a dial indicator before beginning a cut, particularly when tight tolerances are required.