Robbjack STR-401-20-T Square End Mill 5/8 in 4 Flute Carbide

Product Description

The ROBBJACK STR-401-20-T is a solid carbide square end mill designed for precise material removal in milling operations across a wide range of metals and engineered materials. Part of the STR-401 series, this single-end tool features a 5/8 inch cutting diameter, a 7/8 inch length of cut, and a 3-1/2 inch overall length. The 4-flute, fine-pitch geometry with a 30-degree helix angle promotes efficient chip evacuation and a smooth finish in both slotting and peripheral milling. A titanium nitride (TiN) coating adds surface hardness and heat resistance, extending tool life in production environments. This tool is installed and operated by machinists and tooling technicians working with CNC machining centers and manual mills.

The STR-401-20-T is suited for stub-length milling applications where rigidity and reduced deflection are priorities. The 5/8 inch shank diameter matches the cutting diameter, allowing direct mounting in standard ER collet chucks, end mill holders, or shrink-fit tooling. Right-hand cut and right-hand flute orientation make this a standard configuration for conventional and climb milling. Centercutting capability allows plunge entry, adding flexibility for pocket milling operations. Typical applications include face milling, slotting, and contour work on steel, stainless, aluminum, and similar workpiece materials.

Key Features

• Solid carbide construction for rigidity and wear resistance in demanding cuts
• TiN coating increases surface hardness and reduces heat buildup at the cutting edge
• 4-flute, fine-pitch design balances chip clearance with surface finish quality
• 30-degree helix angle promotes smooth cutting action and efficient chip evacuation
• Centercutting geometry enables direct plunge entry without a pilot hole
• Stub-length profile maximizes rigidity and minimizes deflection in short-reach applications

Compatibility

Designed as an OEM-style replacement or direct-use cutting tool for CNC machining centers and manual milling machines accepting a 5/8 inch shank via standard collet or end mill holder tooling systems.

Installation Notes

Installation should be performed by a qualified machinist or tooling technician. Ensure the spindle is fully stopped and locked before inserting or removing the end mill from its holder. Confirm the shank is clean and seated to the recommended engagement depth in the collet or holder before tightening. Verify spindle speed, feed rate, and depth of cut against current tooling data for the workpiece material before starting the cut.