Accupro C911-31218 Thread Mill 5/16-18 Internal Solid Carbide

Product Description

The ACCUPRO C911-31218 is a helical flute thread mill designed for cutting internal 5/16-18 UNC threads in a CNC machining environment. Built from micrograin solid carbide and coated with TiAlN, it delivers the hardness and heat resistance required for threading steel, stainless, aluminum, and other common workpiece materials. The tool features 3 right-hand flutes, a 0.235-inch cutting diameter, and a 0.625-inch length of cut. With 18 teeth per inch and a 0.25-inch shank diameter, it is suited for production threading on machining centers where a single tool handles multiple thread sizes by adjusting the helical interpolation path.

This thread mill is used in job shops, production facilities, and toolrooms for generating precise internal threads in a single helical pass. It is appropriate for through-holes and blind holes where conventional tapping presents tool-breakage risk or where climb-milling thread geometry is preferred. The 0.3125-inch minimum nominal diameter and 0.625-inch length of cut make it a practical choice for shallow-to-moderate thread depth applications in ferrous and non-ferrous materials. No coolant-through capability means external coolant or mist is the standard setup for chip evacuation.

Key Features

• Micrograin solid carbide substrate for rigidity and edge retention
• TiAlN coating improves heat resistance and tool life in ferrous materials
• 3 right-hand helical flutes for efficient chip evacuation on internal threads
• Cuts 5/16-18 UNC internal threads with 0.235-inch cutting diameter
• 0.625-inch length of cut accommodates typical thread engagement depths
• 0.25-inch shank diameter fits standard collet and end mill holder tooling

Compatibility

Designed for use in CNC machining centers capable of helical interpolation for internal thread milling of 5/16-18 UNC threads. Compatible with 0.25-inch collet chucks, ER collets, and end mill holders with a 0.25-inch bore.

Installation Notes

Thread mills require a CNC control capable of helical interpolation — confirm G-code support before setup. Secure the shank fully in the holder to minimize runout, as excessive runout directly impacts thread quality and tool life. Power down the spindle and follow lockout/tagout procedures when changing tooling. Do not use this tool for hand tapping or in manual milling applications.