Scientific Cutting Tools SPTM080ML Thread Mill 4-40 to 4-64

Product Description

The SCIENTIFIC CUTTING TOOLS SPTM080ML is a single profile thread mill engineered for cutting both internal and external threads in the No. 4 thread size range, covering 40 to 64 TPI. Built from submicron-grade solid carbide, it delivers the rigidity and edge retention required for precision thread milling in hardened steels, stainless, aluminum, and other machinable alloys. The tool features a 0.08-inch cutting diameter, a 0.045-inch neck diameter, and a 3/16-inch shank, making it well suited for small-diameter thread work where clearance is tight and tool runout must be minimized. Three flutes provide a balance of chip evacuation and cutting stability at typical thread milling feed rates.

This thread mill is intended for use on CNC machining centers capable of helical interpolation. It handles both through-hole and blind-hole internal threads as well as external boss threads in a single tool, reducing the need for multiple taps or dies in a setup. The 0.25-inch length of cut and 0.25-inch neck length keep the tool compact, which is appropriate for shallow thread depths typical of No. 4 fastener applications in precision mechanical assemblies, instrumentation, and electronics enclosures.

Key Features

• Cuts internal and external threads in a single tool - eliminates separate tap and die setups
• Covers No. 4 thread range from 40 to 64 TPI with one profile
• Submicron-grade solid carbide construction for extended tool life in demanding materials
• 0.045-inch neck diameter provides clearance in confined bore entries
• Bright/uncoated finish suitable for non-ferrous and general-purpose machining applications
• 3-flute geometry balances chip flow and cutting stability at small diameters

Compatibility

Designed for use on CNC machining centers with helical interpolation capability; compatible with No. 4-40 through No. 4-64 thread forms in both internal and external applications across a range of workpiece materials.

Installation Notes

Thread milling requires a CNC control programmed for helical interpolation - confirm machine capability before use. Secure the shank in a precision collet or milling chuck rated for the 3/16-inch shank diameter and verify runout does not exceed the tolerance required for the thread class being cut. Inspect the cutting edges under magnification before each use; solid carbide tools at this diameter are brittle and susceptible to chipping if handled roughly or dropped. Follow the tool manufacturer's recommended speeds, feeds, and axial depth-per-pass guidelines for the specific workpiece material.