Harvey Tool 987146-C3 Thread Mill 1/4-28 Internal Carbide Altin

Product Description

The HARVEY TOOL 987146-C3 is a solid carbide helical flute thread mill designed for cutting internal 1/4-28 UNF threads in a single helical pass. With 3 flutes and an AlTiN coating, it handles the heat and wear demands of ferrous and hardened workpiece materials common in precision machining environments. The cutting diameter is 0.1950 inches, the shank diameter is 0.2500 inches, and the overall length is 2.5 inches. Machinists and CNC operators use this tool when thread milling is preferred over tapping, particularly where blind holes, hard materials, or thread quality requirements make tap breakage a real risk.

This thread mill is suited for CNC machining centers performing internal thread milling operations on ferrous alloys, stainless steels, hardened steels, and similar materials where AlTiN coating provides thermal and wear resistance. The 3-flute geometry and 28 TPI configuration are matched to 1/4-28 UNF internal thread production. It is appropriate for both job shop and production environments where consistent thread quality and tool life in demanding cuts are required. Coolant-through capability is not available on this tool, so external coolant or air blast strategies should be planned accordingly.

Key Features

• Solid carbide construction for rigidity and wear resistance in precision thread milling
• AlTiN coating provides high-temperature resistance and extended tool life in ferrous materials
• 3-flute helical design for efficient chip evacuation during internal thread milling
• Cuts 1/4-28 UNF internal threads at 28 TPI with a 0.1950-inch cutting diameter
• 0.7500-inch length of cut accommodates typical thread depth requirements for this thread size
• No coolant-through — compatible with external coolant or air blast setups

Compatibility

Designed for CNC machining centers capable of helical interpolation, used to produce 1/4-28 UNF internal threads with a minimum nominal bore diameter of 0.2500 inches.

Installation Notes

Thread milling with this tool requires a CNC machining center programmed for helical interpolation — it is not a hand or tap-wrench tool. Ensure the spindle, toolholder, and workpiece fixturing are rigid before running thread milling cycles, as deflection directly affects thread quality. Power down the machine and follow lockout/tagout procedures when changing or inspecting tooling. Do not use this cutter in conventional tapping cycles or hand-tapping applications.