The Carmex Single Threading Insert Holder SR0021H21 is a precision tool holder designed to accept carbide external and internal threading inserts for CNC milling. Part of the Mill-Thread family, it enables reliable, repeatable thread milling on modern CNC machines without the need for traditional taps or dies.

It’s built for shops and professionals—engineers, machinists, and operators—who need fast, consistent threading performance. With this holder, you can leverage indexable carbide inserts to boost cutting speeds, improve productivity, and reduce overall tooling costs on threaded jobs.

• Internal coolant bore: Delivers coolant directly to the cutting edge, helping reduce insert wear, improve chip evacuation, and produce cleaner thread finishes.
• Engineered for Mill-Thread carbide inserts: Supports high-speed threading with multi-tooth carbide inserts, delivering faster cycle times and reliable seating for consistent threads.
• Cost-effective tooling option: Lower tooling costs compared with taps and dies, while maintaining threading quality and repeatable results across multiple jobs.

When you pair the Carmex SR0021H21 with compatible threading inserts, you gain a versatile, low-downtime solution that streamlines your threading workflows. The internal coolant bore helps maintain stable cutting conditions, while the holder’s robust build and Mill-Thread compatibility deliver dependable performance across a range of materials. This means fewer tool changes, more productive cycles, and consistent thread quality that you can trust on every job.