Harvey Tool 70204 Helical Flute Thread Mill 1/4 in Shank

Product Description

The HARVEY TOOL 70204 is a solid carbide helical flute thread mill designed to cut both internal and external threads in a single helical interpolation pass. It handles two common NPT pipe thread sizes: 1/16-27 and 1/8-27, both at 27 teeth per inch (TPI). The cutting diameter measures 0.245 inches, the shank diameter is 0.250 inches, and the length of cut is 0.437 inches. The bright uncoated finish suits a wide range of base materials. This tool is typically installed and run by machinists and CNC operators working in precision threading applications on machining centers.

This thread mill is suited for shops producing or repairing 1/16-27 and 1/8-27 NPT fittings, ports, and pipe connections in metal components. Its helical flute geometry allows the tool to mill full thread profiles on both internal bores and external bosses, making it a versatile option for low-quantity runs, difficult-to-tap materials, and close-tolerance thread work. The compact overall length of 2.5 inches fits standard tool holders on vertical and horizontal machining centers.

Key Features

• Cuts both 1/16-27 and 1/8-27 NPT thread sizes in a single tool
• Internal and external thread milling capability eliminates the need for separate taps and dies
• 3-flute helical geometry for balanced cutting and chip evacuation
• Solid carbide construction provides rigidity and wear resistance
• Bright uncoated finish compatible with a broad range of workpiece materials
• No coolant-through design; flood or mist coolant applied externally

Compatibility

Designed for use on CNC machining centers capable of helical interpolation with a 0.250-inch straight shank tool holder; suitable for threading 1/16-27 and 1/8-27 NPT ports and fittings in ferrous and non-ferrous metals.

Installation Notes

Thread milling requires a CNC control capable of helical interpolation; confirm your CAM program or canned cycle is configured for the correct thread pitch and hand of thread before cutting. Secure the 0.250-inch shank in a precision collet or end mill holder and verify runout before the first pass. Use appropriate cutting speeds and feeds for solid carbide in your workpiece material, and apply external coolant or mist to manage chip evacuation and tool temperature. Inspect threads with a calibrated thread gauge after the first part to confirm fit before production runs.