Harvey Tool 70016-C3 Thread Mill 4-40 3 Flute 1/8 Shank Carbide

Product Description

The HARVEY TOOL 70016-C3 is a solid carbide helical flute thread mill designed to cut 4-40 UN threads in both internal and external applications. Built from micrograin carbide and coated with AlTiN, this tool delivers consistent thread form and wear resistance in demanding materials. The 3-flute design provides a stable cutting action, with a 0.0850-inch cutting diameter and a 0.1750-inch length of cut suited to shallow-depth threading operations. The 2-inch overall length and 1/8-inch shank diameter make it compatible with standard collet holders found on CNC machining centers. Machinists and tool-and-die professionals working with fine-pitch threads rely on this geometry for precise, repeatable results.

This thread mill is intended for use on CNC milling machines and machining centers running helical interpolation routines. The 4-40 UN thread form is common in small fastener applications across electronics, instrument manufacturing, and precision assemblies. Both internal (nut-side) and external (bolt-side) threading operations are supported with a single tool, reducing the need for separate taps or dies. The compact cutting diameter and short length of cut make this tool well-suited to threading blind holes and close-tolerance features where rigid tool control is essential.

Key Features

• Cuts 4-40 UN threads in both internal and external configurations
• Solid micrograin carbide construction for rigidity and extended tool life
• AlTiN coating improves heat resistance and wear performance in ferrous and hard materials
• 3-flute helical geometry provides stable, chatter-resistant cutting action
• 0.0850-inch cutting diameter with 0.1750-inch length of cut for fine-pitch shallow threading
• No coolant-through design; suitable for flood or mist coolant delivery externally

Compatibility

Designed for use in CNC machining centers capable of helical interpolation, with a 1/8-inch round shank compatible with standard ER or precision collet toolholding systems. Intended for 4-40 UN thread form applications in internal and external configurations.

Installation Notes

Installation and operation of this thread mill should be performed by a qualified machinist familiar with CNC helical interpolation programming. Secure the 1/8-inch shank in a precision collet holder, ensuring adequate runout control to maintain thread accuracy. Verify spindle speed, feed rate, and helix pitch in the CAM program before cutting, as these values are determined by the specific material and machine setup. Do not use this tool in manual milling operations or with non-interpolating machine controls.