Osg 5426800 Square End Mill 25/64 in 4 Flute Cobalt

Product Description

The OSG 5426800 is a cobalt square end mill designed for precision milling operations in ferrous and tough alloy materials. Built from M42 cobalt high-speed steel, this double-end tool provides two usable cutting ends, extending tool life and reducing replacement frequency. It features a 25/64 inch (0.3906 inch) cutting diameter, a 1 inch length of cut, and a 4-flute spiral geometry with a 30-degree helix angle optimized for chip evacuation and surface finish. Machinists and tool-and-die professionals install this type of cutter in manual mills and CNC machining centers for slotting, profiling, and peripheral milling applications.

This end mill suits general-purpose milling in job shop and production environments where cobalt tooling is preferred over carbide for its toughness and resistance to chipping. The 1/2 inch shank diameter fits standard ER and straight-bore toolholders common across knee mills and vertical machining centers. With a 4-1/8 inch overall length and a regular-length classification, it is well suited for typical workpiece reach requirements without sacrificing rigidity. Right-hand cut and right-hand flute orientation are standard for conventional and climb milling setups.

Key Features

• M42 cobalt HSS construction for toughness in difficult-to-machine alloys
• Double-end design provides two cutting ends per tool
• 4-flute spiral geometry with 30-degree helix for efficient chip removal
• Uncoated finish suitable for use with cutting fluids on a wide range of materials
• Right-hand cut, right-hand flute for standard milling setups
• Non-centercutting — not intended for direct plunge operations

Compatibility

Designed as an OEM-style replacement or standard tooling selection for 1/2 inch straight-bore and collet-style toolholders used in vertical milling machines and CNC machining centers requiring a 25/64 inch square end mill.

Installation Notes

Installation should be performed by a qualified machinist following the machine tool manufacturer guidelines for toolholder torque and runout specifications. Ensure the spindle is fully stopped and locked before changing or inspecting end mills. Secure the shank to the full recommended insertion depth in the toolholder to prevent pullout under cutting loads. This tool is not centercutting — use a drilled or pre-milled entry point for pocket operations requiring plunge entry.