Carmex 21E12UNMT7 Carbide Thread Mill Insert Un 12 Tpi

Product Description

The CARMEX 21E12UNMT7 is a carbide thread mill insert engineered for external UN threading operations at 12 teeth per inch. Built from submicron carbide in the MT7 manufacturer grade, this insert carries a TiAlN finish that supports higher cutting speeds and extended tool life in demanding machining environments. The insert style is 21E, designed for use in thread milling applications where precise UN-standard thread profiles are required. Machinists and CNC programmers in production shops, job shops, and tool rooms rely on this class of insert for consistent thread geometry on external features.

This insert is suited for external thread milling on materials where a TiAlN coating provides a thermal and wear advantage. It conforms to ANSI B1.1-1989, making it appropriate for UN unified thread form applications across a range of diameters where 12 TPI is the required pitch. Typical use cases include threading on steel, stainless, and cast iron where tool life and thread accuracy are priorities in CNC milling operations.

Key Features

• Submicron carbide substrate for improved toughness and wear resistance
• MT7 grade with TiAlN finish rated for higher-speed external threading
• External UN thread form conforming to ANSI B1.1-1989
• 12 teeth per inch for consistent pitch control on UN threaded features
• Non-conical insert profile in 21E style for straightforward seating in compatible holders
• Thickness of 0.185 inches for dimensional consistency across replacements

Compatibility

Designed for use in thread milling tool holders that accept the 21E insert style. Specific holder compatibility should be verified against CARMEX tooling catalogs for the 21E insert size code.

Installation Notes

Thread mill inserts are installed and replaced by qualified machinists or CNC tooling technicians. Power down and lock out the machine spindle before seating or removing inserts. Use the correct torque driver and insert screw specified by the holder manufacturer - do not over-tighten, as carbide inserts are brittle and can crack under excessive clamp force. Confirm insert seating and runout before cutting to maintain thread quality and avoid tool damage.