Scientific Cutting Tools TMLR234-18ELA Thread Mill 5/16-18

Product Description

The SCIENTIFIC CUTTING TOOLS TMLR234-18ELA is a solid carbide helical flute thread mill designed for cutting internal 5/16-18 UNC threads in CNC machining operations. The tool features a 0.234-inch cutting diameter, a 0.85-inch length of cut, and a 2.5-inch overall length, making it suited for long-reach threading applications where standard-length tools cannot reach. The AlTiN+ coating provides elevated heat resistance and extended tool life in ferrous and hard materials. Machinists and CNC programmers working in production, job-shop, or maintenance environments install this tool in machining centers equipped with helical interpolation capability.

This thread mill is used for producing internal 5/16-18 UNC threads in a single helical pass, allowing one tool to cut a range of thread depths without requiring a dedicated tap per hole depth. The long-reach design accommodates recessed bores and deep-cavity threading scenarios. The 3-flute, right-hand flute geometry balances chip evacuation with cutting stability. A 1/4-inch shank diameter makes it compatible with standard ER collets and other precision tool holders commonly used on vertical and horizontal machining centers.

Key Features

• Solid carbide submicron-grade substrate for rigidity and wear resistance in demanding cuts
• AlTiN+ coating for high-temperature performance and extended tool life in ferrous materials
• Long-reach thread mill type allows access to recessed or deep-cavity internal threads
• 3-flute right-hand helical geometry balances chip flow and cutting force
• No coolant-through design; suitable for flood or mist coolant applied externally
• Single tool handles variable thread depths, reducing tooling inventory compared to tap sets

Compatibility

Designed for cutting internal 5/16-18 UNC threads with a 0.3125-inch minimum nominal diameter. Intended for use in CNC machining centers with helical interpolation and a standard 1/4-inch tool holder or collet system.

Installation Notes

Install in a precision collet chuck or end mill holder to minimize runout, which directly affects thread quality and tool life. Program the tool path using the machining center control's helical interpolation cycle and confirm the correct thread direction before cutting. Secure workholding is essential, as vibration at depth degrades thread form and accelerates tool wear. Always verify spindle direction and tool projection length before engaging the cut.