Harvey Tool 70066-C3 Thread Mill 3/8-24 4 Flute Solid Carbide

Product Description

The HARVEY TOOL 70066-C3 is a solid carbide helical flute thread mill designed for cutting 3/8-24 UNF threads in both internal and external applications. With 4 flutes and an AlTiN coating, it handles the thermal and abrasive demands of threading in ferrous and hard materials. The cutting diameter is 0.2850 inches with a 5/16-inch (0.3125-inch) shank diameter, making it compatible with standard collet chucks and end mill holders. Length of cut is 0.750 inches and overall length is 3.0 inches. This tool is installed and operated by machinists and CNC programmers in production and job shop environments.

This thread mill is suited for machining centers and CNC milling machines capable of helical interpolation. It produces 3/8-24 UNF threads in a single helical pass, eliminating the need for a dedicated tap and allowing thread size adjustment via the toolpath offset. Typical applications include aerospace, automotive, and general metalworking where thread quality and tool life in tough materials are critical. The AlTiN coating extends cutting life in hardened steels, stainless steels, and high-temperature alloys. Coolant-through is not supported on this tool.

Key Features

• Cuts 3/8-24 UNF threads internally and externally in a single helical interpolation pass
• Solid carbide construction for rigidity and dimensional stability in demanding materials
• AlTiN coating provides high heat resistance for dry or minimal-lubrication cutting in ferrous and hardened materials
• 4-flute geometry balances chip evacuation and surface finish on thread forms
• 0.750-inch length of cut accommodates typical thread depth requirements for 3/8-24 fastener applications
• 3.0-inch overall length provides clearance for most standard workholding setups

Compatibility

Designed for use in CNC machining centers capable of helical interpolation; accepts standard 5/16-inch collet chucks and end mill holders. Suitable for cutting 3/8-24 UNF threads with a minimum nominal diameter of 0.375 inches.

Installation Notes

This tool is intended for use by qualified machinists and CNC programmers. Verify spindle speed, feed rate, and helical pitch settings in the CAM program or G-code before running. Secure the shank fully in a collet or end mill holder to the manufacturer-recommended engagement depth before starting the spindle. Do not use this tool in a manual mill or drill press; helical interpolation requires coordinated 3-axis CNC motion.