Osg 5451100 Square End Mill 1/2 in 4-flute Cobalt Long

Product Description

The OSG 5451100 is a cobalt square end mill designed for milling operations in ferrous and difficult-to-machine materials. Built from M42 cobalt high-speed steel, this tool delivers improved heat and wear resistance compared to standard HSS end mills. It features a 0.5 inch cutting diameter, a 2 inch length of cut, and a 4-inch overall length, placing it in the long series category. The 4-flute, right-hand spiral configuration with a 30-degree helix angle provides efficient chip evacuation and a smooth cutting action on a wide range of workpiece materials. This is a single-end, uncoated tool with a right-hand flute direction.

This end mill is suited for peripheral and slot milling in job shop, tool room, and production environments. The long series configuration makes it appropriate for applications requiring extended reach into deep pockets or stepped features. The 0.5 inch shank diameter matches the cutting diameter, allowing it to seat directly in standard 1/2 inch collet chucks, end mill holders, or Weldon-style tool holders. The Series 545 designation identifies this as part of OSG's long cobalt square end mill line. Machinists and CNC operators working with stainless steel, alloy steel, cast iron, and similar materials will find this tool a practical general-purpose option.

Key Features

• M42 cobalt HSS construction for elevated red hardness and wear resistance
• 4-flute spiral design with 30-degree right-hand helix for efficient chip removal
• Long series with 2 inch length of cut for deep pocket and extended reach applications
• 0.5 inch shank diameter matches cutting diameter for direct chuck mounting
• Uncoated finish suitable for use with cutting fluids and oils
• Non-centercutting design — not intended for direct plunge entry

Compatibility

Designed as an OEM-style fit for standard 1/2 inch end mill holders, collet chucks, and Weldon-style tool holders. Part of the OSG Series 545 long cobalt square end mill line.

Installation Notes

Installation and use should be performed by a qualified machinist or CNC operator. Ensure the spindle is fully stopped and the machine is powered down before changing tooling. Secure the shank to the full recommended engagement depth in the holder to minimize runout and tool pullout risk. This is a non-centercutting tool and should not be used for direct axial plunge cuts without a pre-drilled entry hole or ramping strategy.