Robbjack S1-301-08 Square End Mill 1/4 in 3 Flute Carbide

Product Description

The ROBBJACK S1-301-08 is a solid carbide square end mill designed for precision milling operations in metal cutting and general machining applications. The tool features a 0.2500-inch cutting diameter with a 0.5000-inch length of cut and a 2-inch overall length in a stub-length configuration. Three spiral flutes with a 30-degree helix angle promote efficient chip evacuation and smooth cutting action. The right-hand cut, right-hand flute geometry and centercutting capability allow for both peripheral milling and plunge cutting. Manufactured from C2-grade solid carbide and supplied uncoated, this end mill is suited for use on CNC machining centers and manual mills by machinists and toolroom technicians.

The S1-301-08 is appropriate for a wide range of machining tasks including slotting, profiling, and face milling on ferrous and non-ferrous materials. The stub-length body provides increased rigidity compared to standard or long-reach variants, making it a reliable choice when minimizing deflection is critical. The straight cylindrical shank fits standard ER collet chucks and end mill holders sized for 1/4-inch shank tooling. This tool is part of the ROBBJACK S1-301 series, which targets general-purpose solid carbide milling at consistent dimensional tolerances.

Key Features

• 0.2500-inch cutting diameter with a tolerance of +0.000 / -0.002 inches for controlled fit and finish
• Three spiral flutes at a 30-degree helix angle for efficient chip flow and reduced cutting forces
• Centercutting design enables direct plunge entry without pre-drilling
• Solid C2-grade carbide construction provides hardness and wear resistance in demanding cuts
• Stub-length body maximizes rigidity and minimizes tool deflection in tight setups
• Uncoated finish suitable for use with cutting fluid in a broad range of base materials

Compatibility

Designed as an OEM-style replacement or direct-use tool for applications requiring a 1/4-inch shank, 1/4-inch diameter, 3-flute solid carbide square end mill in the ROBBJACK S1-301 series.

Installation Notes

Installation is performed by machinists or CNC operators using a properly sized collet chuck or end mill holder rated for 1/4-inch straight cylindrical shanks. Ensure the spindle and machine are fully powered down and locked out before changing tooling. Confirm shank seating depth meets the tool holder manufacturer's minimum engagement specification before tightening. Always verify runout with a dial indicator after installation to maintain dimensional accuracy and tool life.