Accupro C911-00440 Thread Mill 4-40 Internal 2 Flute Tialn

Product Description

The ACCUPRO C911-00440 is a helical flute thread mill designed for cutting internal 4-40 UNC threads in a single helical pass. Built from micrograin solid carbide and coated with TiAlN, it delivers consistent thread form and extended tool life in ferrous and non-ferrous materials. The 2-flute geometry supports chip evacuation in tight bores, while the 0.085 inch cutting diameter suits small-bore thread milling applications where taps may not be practical. At 40 teeth per inch and a 0.219 inch length of cut, this tool is well matched to standard 4-40 thread depth requirements. Machinists and tooling professionals in precision machining, mold and die, and aerospace component shops are the primary users.

This thread mill is suited for CNC machining centers running internal thread milling cycles on small-diameter holes. The 1/8 inch shank diameter makes it compatible with standard ER collet systems and small-bore tool holders common in precision shops. It is appropriate for use on steel, stainless, aluminum, and other machinable alloys where a 4-40 UNC internal thread is required. Because the cutting diameter is smaller than the thread minor diameter, the tool can be used for thread milling in through-holes and blind holes without requiring a separate tap or thread-forming step.

Key Features

• Micrograin solid carbide construction for rigidity and wear resistance in small-diameter thread milling
• TiAlN coating provides thermal protection and extends tool life in dry or semi-dry cutting conditions
• 2-flute helical design promotes chip evacuation in confined internal bores
• 0.085 inch cutting diameter sized for 4-40 UNC internal thread profiles
• 0.219 inch length of cut accommodates standard 4-40 thread engagement depths
• No coolant-through design — suited for external coolant or dry machining setups

Compatibility

Designed for CNC machining centers using helical interpolation thread milling cycles to produce 4-40 UNC internal threads. Fits standard 1/8 inch ER collet chucks and compatible small-bore tool holders.

Installation Notes

Thread mills of this type are installed by licensed machinists or CNC tooling technicians using a calibrated collet or tool holder with proper runout tolerance. Ensure the spindle is fully stopped and the machine is in a safe state before changing or measuring the tool. Program helical interpolation per the control manufacturer and tool manufacturer specifications — do not use single-pass tapping cycles with this tool. Verify cutting parameters against the workpiece material before production runs.