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Carmex Carbide Threading Insert - NPT - TiAlN Coated - 21-11.5NPT
| Application | Threading |
| Thread Form | NPT |
| Internal or External | Internal & External |
| Insert Size | 21 |
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Introducing the Carmex Carbide Threading Insert for NPT, a TiAlN-coated carbide insert designed for professional threading tasks. Built for machinists and fabrication shops, it delivers precise, repeatable NPT and common-thread profiles with durable performance on both internal and external threads.
- Coating: TiAlN coating enhances wear resistance and heat tolerance for longer tool life in demanding threading applications.
- Material: Carbide substrate provides stiffness, sharpness, and consistent cutting action across different thread forms.
- Model/Code: 21-11.5NPT, specifically tailored for NPT thread work and related profiles.
- Length options: Five lengths available (12 mm to 40 mm) to fit various hole depths, collars, and shoulder constraints.
- Pitch range: Compatible with pitches from 0.5 mm (32 TPI) to 6.0 mm (4 TPI), covering the most common threading needs.
- Double-sided edges: Insert is double-sided with two cutting edges on most profiles, extending usage life (note: BSPT/NPT/NPTF/American Buttress/API RD may not use the second edge).
- Internal/External threading compatibility: For many thread profiles, the same insert can machine both internal and external threads, reducing tool changes and inventory (with profile exceptions such as ISO/UN/NPSM/UNJ/Acme).
Designed for efficiency and reliability, this insert supports precise thread forms across a wide range of standard profiles while delivering the stability of TiAlN-coated carbide. It’s an excellent choice for pipe fittings, valves, housings, and other components where consistent thread quality and tool life matter—whether you’re setting up batch runs or performing quick-turn jobs.
Part Numbers
- Protool Part Number
- 21-11.5NPT
- Brand
- Carmex
- Category
- Thread Mill
Delivery
Free UK mainland delivery on orders over £50 ex VAT. In-stock items ordered before 4:30pm are dispatched the same working day. Full delivery information.
Returns
14-day returns on unused stock items in original packaging. Special-order and bespoke tooling is non-returnable. Read our returns policy.
Technical Support
Over 30 years of machining experience behind the counter. Call 01732 887334, Mon–Thurs 8:30–17:30, Fri 8:30–16:30.
Trade Accounts
Credit accounts, contract pricing and scheduled call-off orders available for trade customers. Apply for an account.
What time are Protool open?
We are open Monday to Friday between 8:30am and 5pm.
Do you offer Free Next Day delivery?
Yes! We offer Free Next Day delivery via Royal Mail Tracked 24 on all orders over £50 ex VAT*. We also offer Free DPD Local Next Day delivery on all orders over £100 ex VAT*.
We also offer the following:
- Royal Mail Tracked 24 — £5.90 (FREE on orders over £50 ex VAT*). Order before 4:30pm for next day delivery. No signature required.
- DPD Local Next Day — £8.00 (FREE on orders over £100 ex VAT*). Standard next day delivery to UK mainland addresses.
- Royal Mail Special Delivery — £12.50. Guaranteed delivery before 1pm the next working day.
- DPD Saturday Delivery — £25.00. Must be ordered on Friday before 4pm. Pre-12pm delivery.
For delivery to Scottish Highlands & Islands, Northern Ireland, Republic of Ireland, or overseas locations, additional charges apply. Please see our delivery page for full details, or call us on 01732 887 334.
*T's & C's and exclusions apply. Please see our delivery page for more information on all our services.
Full Range: Carmex Carbide Threading Inserts - NPT - TiAlN Coated
View full collection →You are viewing 21-11.5NPT. Click any other SKU to view its full details.
| Product SKU | Insert Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|
| 12-18NPT | 12 | 18 | £32.74 | In Stock | |
| 14-14NPT | 14 | 14 | £32.74 | In Stock | |
| 14-18NPT | 14 | 18 | £32.74 | In Stock | |
| 21-11.5NPT Viewing | 21 | 11.5 | £43.74 | In Stock | |
| 21-14NPT | 21 | 14 | £43.74 | In Stock | |
| 30-11.5NPT | 30 | 11.5 | £60.05 | In Stock | |
| 30-8NPT | 30 | 8 | £60.05 | In Stock | |
| 40-11.5NPT | 40 | 11.5 | £103.37 | 5 days | |
| 40-8NPT | 40 | 8 | £103.37 | 5 days |
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