Osg 5574100 Square End Mill 7/8 in 4 Flute Cobalt Extra Long

Product Description

The OSG 5574100 is a cobalt square end mill designed for heavy-duty milling applications in ferrous and high-strength materials. Built to Series 557 standards, this single-end tool features a 7/8 inch cutting diameter, a 5 inch length of cut, and a 7-1/4 inch overall length, placing it in the extra-long category. The 30-degree spiral helix promotes efficient chip evacuation during deep-pocket and side-milling operations. Four flutes provide a balance of chip clearance and surface contact. The uncoated cobalt construction, rated to material grade M42, offers improved heat resistance and edge retention compared to standard HSS, making it well-suited for interrupted cuts and tough alloys.

This end mill is used in vertical and horizontal machining centers, knee mills, and manual milling machines where extended reach into deep cavities or long-wall features is required. The extra-long length of cut makes it appropriate for moldmaking, die work, and structural component machining where standard-length tooling cannot reach. Right-hand cut and right-hand flute geometry match conventional machine spindle rotation. The shank diameter matches the cutter diameter at 7/8 inch, simplifying collet or end mill holder selection. This tool does not feature a chipbreaker, center-cutting capability, variable helix, or variable index geometry.

Key Features

• 7/8 inch cutting diameter with matching 7/8 inch shank for secure, concentric clamping
• 5 inch length of cut for deep-pocket and extended-reach milling operations
• Cobalt M42 material grade for improved heat resistance and edge retention over standard HSS
• 30-degree spiral helix promotes smooth chip flow and reduces cutting forces
• 4-flute configuration balances material removal rate with chip clearance
• Right-hand cut, right-hand flute geometry compatible with standard machine spindle rotation
• Uncoated finish — suitable for use with or without cutting fluid

Compatibility

Designed as an OEM-style replacement or direct-fit tooling option for standard 7/8 inch collets, end mill holders, and milling chucks used in vertical machining centers, knee mills, and manual milling machines.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Ensure the machine spindle is fully stopped and locked out before installing or removing the end mill. Seat the shank fully into the holder and torque set screws or collet nuts to the tool holder manufacturer's specifications. Verify runout with a dial indicator before beginning any cut, as excessive runout accelerates tool wear and reduces surface finish quality.