Carmex B0250C0420UN Thread Mill 1/4-20 Internal 3 Flute Carbide

Product Description

The CARMEX B0250C0420UN is a helical flute thread mill designed for cutting internal 1/4-20 UNC threads in a CNC machining environment. The tool is manufactured from solid carbide in material grade MT7 and carries a TiAlN coating for heat resistance and extended tool life at elevated cutting speeds. With 3 right-hand flutes and a cutting diameter of 0.185 inches, it produces clean thread forms in a single helical interpolation pass. Coolant-through capability supports chip evacuation in blind holes and deep-thread applications. The 1/4-inch shank diameter fits standard collet and end mill holders.

This thread mill is suited for job shops, production machining cells, and toolroom operations where CNC milling centers handle threaded-hole features. The 1/4-20 UNC thread form is common in general mechanical assembly, fixturing, and light structural applications. At 2.5 inches overall length with a 0.48-inch length of cut and a 2.02-inch shank length, the tool reaches threads in moderately deep bores without excessive overhang. It is installed by machinists and CNC programmers running helical interpolation cycles on 3-axis or 5-axis machining centers.

Key Features

• Solid carbide MT7 grade construction for rigidity and wear resistance in ferrous and non-ferrous materials
• TiAlN coating provides thermal barrier and extends tool life at high cutting speeds
• 3 right-hand helical flutes for smooth cutting action and efficient chip flow
• Coolant-through design supports chip evacuation in blind holes and high-feed operations
• Cuts 1/4-20 UNC internal threads in a single helical interpolation pass, reducing cycle time versus tapping
• 1/4-inch shank diameter fits standard ER collets and side-lock end mill holders

Compatibility

Designed for use on CNC machining centers capable of helical interpolation, producing 1/4-20 UNC internal threads. Compatible with standard 1/4-inch collet chucks and end mill holders.

Installation Notes

This tool is installed and operated by machinists and CNC programmers. Confirm the machining center spindle and control support helical interpolation before use. Secure the shank fully in a balanced collet or shrink-fit holder and verify runout before cutting. Follow the tooling manufacturer and machine builder guidelines for feed rate, spindle speed, and coolant pressure when programming the helical interpolation cycle.