Iscar 3319990 Carbide Thread Mill Insert 18 Tpi Un

Product Description

The ISCAR 3319990 is a carbide thread mill insert designed for external UN thread milling at 18 threads per inch (TPI). The insert carries the MT-LNHU style designation with a 1403 size code and is manufactured to the IC908 grade, featuring a TiAlN finish applied via PVD coating process. This insert seats into compatible thread mill bodies and is used to produce precise external unified national (UN) thread forms on CNC machining centers. Installation and operation are handled by machinists and CNC programmers working in precision metalworking environments where thread accuracy and insert durability are essential.

This insert is suited for external thread milling operations across a broad range of workpiece materials, including hardened steels, cast irons, stainless and exotic alloys, and general-purpose ferrous materials. The IC908 grade with PVD-applied TiAlN coating supports performance in applications where heat resistance and edge toughness are required. It is typically used in production or job-shop CNC milling setups where thread mill inserts are indexed and replaced as part of routine tooling maintenance. The insert conforms to ISO 13399 standards, making it compatible with tooling data systems used in modern CNC programming workflows.

Key Features

• MT-LNHU insert style with 1403 size code for indexed thread mill toolholders
• IC908 carbide grade with TiAlN coating applied by PVD process for heat and wear resistance
• Designed for external UN thread milling at 18 TPI with a 1.411 mm pitch
• Compatible workpiece material codes: H, K, M, P, and S covering hardened steels, cast irons, stainless, titanium, and general steel
• Conforms to ISO 13399 tooling data standard for CNC integration

Compatibility

Designed as an OEM-style replacement insert for MT-LNHU style thread mill bodies accepting 1403 size inserts used in external UN thread milling applications.

Installation Notes

Thread mill inserts are installed and indexed by machinists or CNC tooling technicians. Shut down and lock out the machine spindle before changing or indexing any insert. Use the correct torque wrench or insert key specified by the toolholder manufacturer to seat the insert properly. Do not operate the insert outside the feed, speed, and depth parameters established for the IC908 grade and the specific workpiece material.