Osg 5427400 Square End Mill 21/32 in 4 Flute Cobalt

Product Description

The OSG 5427400 is a cobalt square end mill designed for milling operations in ferrous and hard materials where high-speed steel falls short. Built to Series 542 specifications, this double-end tool features a 21/32 inch (0.6563 inch) cutting diameter, a 1-5/8 inch length of cut, and a 3/4 inch shank diameter with an overall length of 5-5/8 inches. The 4-flute spiral geometry with a 30-degree helix angle promotes efficient chip evacuation and surface finish quality. Material grade M42 cobalt provides elevated hot hardness, making this end mill well suited for stainless steels, alloy steels, and similar tough workpiece materials. It is uncoated and arrives ready for use in conventional machining setups.

This end mill is used in vertical machining centers, knee mills, and manual milling machines across job shops, tool rooms, and production environments. It is suited for side milling, slotting, and peripheral profiling in ferrous alloys, stainless steels, and similar materials. The regular-length configuration fits standard toolholders and collet chucks accepting a 3/4 inch shank. Right-hand cut and right-hand flute orientation is standard for conventional spindle rotation. The double-end design allows the second end to be placed into service after the first end wears, extending usable tool life per unit.

Key Features

• M42 cobalt construction for elevated hot hardness in tough and abrasive workpiece materials
• Double-end design — both ends are usable cutting edges, extending tool life
• 4-flute spiral geometry with 30-degree helix angle for balanced chip evacuation and surface finish
• Right-hand cut, right-hand flute — compatible with standard CNC and manual mill spindle rotation
• Uncoated finish — no coating buildup concerns; suitable for re-sharpening
• Non-centercutting — intended for peripheral and side milling, not plunge entry

Compatibility

Designed as an OEM-style replacement or direct-use cutting tool for milling applications requiring a 3/4 inch shank square end mill with a 21/32 inch cutting diameter, compatible with standard collet chucks, end mill holders, and Weldon-style toolholders accepting a 3/4 inch shank.

Installation Notes

This tool is installed by machinists and tool room operators using standard toolholding equipment rated for the 3/4 inch shank diameter. Ensure the spindle and machine are at a full stop and power is locked out before changing tooling. Confirm holder runout is within acceptable limits before beginning a cut, as excessive runout accelerates edge wear and reduces surface finish quality. Because this end mill is non-centercutting, do not attempt direct plunge milling — use a ramp or helical entry strategy instead.