Robbjack NR-303-10 Square End Mill 5/16 Inch 3 Flute

Product Description

The ROBBJACK NR-303-10 is a solid carbide square end mill designed for precise milling operations in metalworking and machining applications. Part of the NR-303 series, this tool features a 5/16-inch diameter, a 13/16-inch length of cut, and a 2-1/2-inch overall length. The 3-flute, right-hand spiral geometry with a 30-degree helix angle promotes efficient chip evacuation and smooth cutting action. The uncoated solid carbide construction in material grade C2 delivers the rigidity and edge retention needed for accurate interpolation, slotting, and profiling cuts.

This end mill is suited for general-purpose milling in job shop, tool room, and production machining environments. Its centercutting capability allows plunge entry directly into the workpiece, making it versatile for both full-slot and peripheral milling operations. The straight-cylindrical shank is compatible with standard ER collet chucks, end mill holders, and shrink-fit toolholders sized for 5/16-inch shank diameter. Typical materials include aluminum alloys, mild steels, cast iron, and similar machinable metals at appropriate feeds and speeds for uncoated carbide.

Key Features

• Solid carbide construction for rigidity and long tool life
• 3-flute spiral design with 30-degree helix angle for efficient chip evacuation
• Centercutting geometry allows direct plunge entry into the workpiece
• Right-hand cut and right-hand flute orientation - compatible with standard spindle rotation
• Straight-cylindrical shank fits standard collet and end mill holder systems
• Regular length profile for general-purpose milling tasks

Compatibility

Designed as a general-purpose replacement or new-installation end mill for any machine tool spindle accepting a 5/16-inch straight-cylindrical shank via collet chuck, end mill holder, or shrink-fit toolholder.

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 to the full recommended engagement depth in the toolholder and torque the retention mechanism per the toolholder specification. Verify runout with a dial indicator before beginning a production cut, as excessive runout accelerates tool wear and reduces surface finish quality.