Thread Mills

From UN to Custom: Find Your Perfect Thread Fit

You need threads that fit right the first time—every time. Whether you're machining aerospace components, automotive parts, or high-precision equipment, precision matters. At Scientific Cutting Tools, we design thread mills that help you cut with confidence. Choose from five standard thread styles—UN, UNJ, Metric, Pipe, and ACME—or send us your specs for a fully custom solution. Whatever the job, we’ve got the right tool to keep your shop running smoothly.

UN Threads

  • Standard Unified National threading

  • Ideal for general-purpose threading in North American applications

  • Available in both internal and external options

UNJ External Threads

  • External threading with root controlled radius

  • Common in aerospace and high-performance assemblies

  • Designed for fatigue resistance

Metric Threads

  • ISO metric threading options for
    international standards

  • Available in coarse and fine pitches

  • Optimized for global compatability

Pipe Threads

  • Tapered and straight pipe threading (NPT, NPTF, BSPP, BSPT)

  • Engineered for leak-resistant connections

  • Suitable for hydraulic and pneumatic
    systems

ACME Threads

  • Strong, load bearing profile

  • Used in linear motion applications

  • Multiple pitch and class options available

Custom Threads

  • We machine to your specs - whether
    it’s form, pitch, or coating

  • Ideal for R&D, specialty OEM applications, and problem-solving

  • Submit a drawing or consult with our engineering team

Wondering when to use a thread mill instead of a tap?

This video breaks down the key differences - and shows why thread mills can be the smarter choice for tough materials, blind holes, and precision-critical parts.

Emmett Quigley, NASA Ames Research Center

“I love your thread mills.”

Support That Starts
Before the Cut

We don’t just sell tools—we back them with the knowledge and support you need to machine with confidence. Whether you're looking to sharpen your threading strategy or need help on a current job, these resources are here to help.

Thread Milling Webinar. Watch our on-demand webinar to deepen your understanding of thread milling fundamentals, tooling selection, and programming best practices.

DXF and STEP File Downloads. Get CAD-ready files for faster CAM programming and toolpath simulation.

Thread Mill Code Generator. Our calculator takes the guesswork out of programming. Generate your thread milling code based on your specs.

Explore Our Tech Support Pages. From troubleshooting tips to feeds and speeds guidance, our Technical Support hub is your go-to resource.

Still need help? Our in-house engineers are just a click away. Submit a question and we’ll get back to you quickly.