Harvey Tool 987156-C3 Thread Mill 5/16-24 Solid Carbide

Product Description

The HARVEY TOOL 987156-C3 is a solid carbide helical flute thread mill designed for cutting internal 5/16-24 UNF threads. With 3 flutes and an AlTiN coating, it delivers precise thread forms in hardened and abrasive materials. The cutting diameter measures 0.2450 inches with a length of cut of 0.9580 inches, making it well suited for threading shallow-to-moderate depth bores. Machinists and toolroom operators use this tool on CNC machining centers where helical interpolation produces accurate threads in a single tool path. The AlTiN coating improves heat resistance and extends tool life in dry or semi-dry cutting conditions.

This thread mill is intended for internal threading operations on ferrous and non-ferrous workpieces requiring a 5/16-24 thread form. It is commonly used in precision machining environments including aerospace, automotive, and general metalworking shops. The 0.3125 inch shank diameter fits standard ER collet chucks and shrink-fit holders used on vertical and horizontal machining centers. At 3.0 inches overall length, it provides adequate reach for most standard through-hole and blind-hole threading applications where helical interpolation is programmed at the control.

Key Features

• Cuts 5/16-24 UNF internal threads with 24 teeth per inch
• Solid carbide construction for rigidity and dimensional stability
• AlTiN coating resists heat and reduces built-up edge in abrasive materials
• 3-flute geometry balances chip evacuation with cutting edge strength
• 0.2450 inch cutting diameter with 0.9580 inch length of cut
• No coolant-through design — suitable for external coolant or mist applications

Compatibility

Designed for use in CNC machining centers capable of helical interpolation, with a 0.3125 inch shank compatible with standard collet and shrink-fit toolholding systems requiring a 5/16-24 internal thread mill.

Installation Notes

Installation and operation should be performed by a qualified machinist or CNC programmer familiar with thread milling cycles. Confirm toolholder runout is within acceptable tolerance before use, as excess runout directly affects thread quality. Program the helical interpolation path to match the 5/16-24 thread pitch and verify the bore diameter provides sufficient clearance for the 0.2450 inch cutting diameter. Power down and lock out the spindle before changing or inspecting the tool.