Osg 5818200 Square End Mill 0.1772 in 4 Flute Cobalt

Product Description

The OSG 5818200 is a cobalt square end mill designed for milling operations requiring consistent performance in ferrous and difficult-to-machine materials. Built to Series 581 specifications, this single-end tool features a 0.1772-inch cutting diameter, a 4-flute geometry, and a 30-degree helix angle that promotes efficient chip evacuation and stable cutting action. The 3/8-inch shank diameter accommodates standard ER and side-lock toolholders commonly found in vertical machining centers and knee mills. Machinists and toolroom technicians install this end mill for profiling, slotting, and peripheral milling where a small-diameter cobalt tool is specified.

This end mill is suited for general-purpose metalworking in job shop and production environments. The 0.5-inch length of cut and 2-3/8-inch overall length make it well-proportioned for shallow-to-moderate depth passes in steel, stainless, and alloy materials. The right-hand cut and right-hand spiral flute configuration are standard for conventional and climb milling on CNC and manual equipment. No chipbreaker geometry means consistent contact along the full cutting edge length, which is appropriate for finish and semi-finish passes.

Key Features

• Cobalt construction (M42 material grade) provides elevated heat resistance compared to standard HSS, extending tool life in harder work materials
• 4-flute spiral design with 30-degree helix angle for balanced chip flow and surface finish quality
• Uncoated finish — compatible with cutting fluid application for temperature management
• Right-hand cut, right-hand flute — standard orientation for the majority of milling setups
• Non-centercutting geometry — suited for peripheral and side milling, not plunge entry
• Series 581 regular-length profile provides rigidity in short-reach applications

Compatibility

Designed as an OEM-specification cobalt square end mill for use in standard 3/8-inch collet, ER, or side-lock toolholding systems on CNC machining centers and manual knee mills.

Installation Notes

Installation is performed by qualified machinists or toolroom personnel. Ensure the machine spindle is fully stopped and the tool is secured with the appropriate torque on the toolholder before operation. Confirm runout with a dial indicator after clamping, as excessive runout accelerates wear on small-diameter end mills. Because this tool is non-centercutting, do not use it for direct plunge entry into solid material.