Robbjack NR-404-02.5 Square End Mill 5/64 in 4 Flute

Product Description

The ROBBJACK NR-404-02.5 is a solid carbide square end mill designed for precision milling operations in metalworking and machining applications. With a 5/64 inch (0.0781 inch) mill diameter and a 1/4 inch length of cut, this tool handles slotting, profiling, and peripheral milling in tight geometries. The 4-flute, right-hand spiral configuration with a 30-degree helix angle promotes efficient chip evacuation and smooth cutting action. It is uncoated and manufactured from C2-grade solid carbide, offering rigidity and wear resistance in a compact form factor. Licensed machinists and CNC operators working in tool rooms or production environments are the primary users of this end mill.

This end mill is suited for milling ferrous and non-ferrous materials in applications where small-diameter tooling is required. The 1/8 inch straight-cylindrical shank fits standard collet chucks and end mill holders commonly found on CNC machining centers, vertical mills, and manual knee mills. Its regular-length, centercutting design allows plunge entry and full slot milling in a single tool. The NR-404 series is built for applications demanding close tolerances and consistent performance at small diameters.

Key Features

• 5/64 inch mill diameter (0.0781 inch) with a mill diameter tolerance of +0.001 / -0.000 inches
• 4-flute, right-hand cut and right-hand spiral flute design with 30-degree helix angle
• Centercutting geometry allows direct plunge entry without pre-drilling
• C2-grade solid carbide construction for rigidity and extended tool life
• 1/8 inch straight-cylindrical shank with a shank diameter tolerance of -0.0001 / -0.0002 inches
• Uncoated finish suitable for applications where coating is not required or where regrinding is anticipated

Compatibility

Designed as an OEM-style replacement or direct-use tooling option for standard 1/8 inch collet chucks and end mill holders on CNC machining centers, vertical mills, and manual milling machines requiring small-diameter square end mills.

Installation Notes

Installation should be performed by a qualified machinist or CNC operator. Ensure the machine spindle is fully stopped and locked out before changing tooling. Seat the shank fully into the collet or tool holder to the recommended grip length before tightening to the tool holder manufacturer's specification. Confirm runout with a dial indicator after installation, as small-diameter end mills are sensitive to collet condition and holder concentricity.