Harvey Tool 987144-C3 Thread Mill 1/4-20 Internal 3 Flute Carbide

Product Description

The HARVEY TOOL 987144-C3 is a helical flute thread mill designed for cutting internal 1/4-20 threads in a CNC milling environment. Built from solid carbide and coated with AlTiN (aluminum titanium nitride), this tool delivers consistent thread form and extended tool life in ferrous and hardened materials. It runs a 0.1950-inch cutting diameter with a 0.7500-inch length of cut, and the 1/4-inch shank fits standard collet chucks and end mill holders. Three helical flutes promote chip evacuation and reduce cutting forces during the threading pass. CNC machinists and toolroom operators use this tool in production and precision machining applications.

This thread mill is suited for internal 1/4-20 UNC thread production in materials including steel, stainless steel, cast iron, and similar alloys where AlTiN coating provides thermal resistance and wear protection. At 2.5 inches overall length with a 1/4-inch shank diameter, it fits VMCs and HMCs with standard toolholding. It is used in job shops, aerospace machining cells, and production environments where thread milling is preferred over tapping for accuracy control, thread depth flexibility, or difficult-to-machine materials. Coolant-through is not supported on this tool.

Key Features

• Cuts internal 1/4-20 UNC threads at 20 teeth per inch
• Solid carbide construction for rigidity and dimensional stability
• AlTiN coating extends tool life in high-heat and abrasive cutting conditions
• Three helical flutes support chip flow and reduce cutting load
• 0.1950-inch cutting diameter with 0.7500-inch length of cut
• No coolant-through — external coolant or air blast applies

Compatibility

Designed for use in CNC milling machines with standard 1/4-inch collet or end mill toolholding; suitable for internal 1/4-20 UNC thread milling applications where the minimum nominal bore diameter is 1/4 inch.

Installation Notes

Installation and operation of this tool should be performed by a qualified CNC machinist or toolroom professional. Secure the 1/4-inch shank in a properly sized, clean collet or end mill holder and verify runout before cutting. Program helical interpolation at the correct thread pitch; do not use this tool as a standard end mill or tap. Follow machine tool builder guidelines and applicable shop safety procedures when setting speeds and feeds for solid carbide tooling.