Please log in here to access all benefits, including promotional discounts and faster checkouts.

Carmex Carbide Threading Insert - NPT - TiAlN Coated - 40-8NPT
| Application | Threading |
| Thread Form | NPT |
| Internal or External | Internal & External |
| Insert Size | 40 |
| Pitch | 8 |
Learn more about Klarna
The Carmex Carbide Threading Insert for NPT and common thread profiles is a TiAlN-coated solution built for machinists who need reliable, high-precision threading across internal and external surfaces.
- Five length options: Inserts are available in five lengths, ranging from 12 mm to 40 mm, to fit a variety of hole depths and turning passes.
- Broad thread compatibility: Covers all common thread profiles, reducing the need to stock multiple tool types.
- Pitch range flexibility: Capable of handling pitches from 0.5 mm (32 TPI) to 6.0 mm (4 TPI) for diverse applications.
- Double-sided cutting edges: Each insert features two cutting edges to maximize usable life, with exceptions for BSPT / NPT / NPTF / American Buttress / API RD.
- Internal & external threading: For many profiles, the same insert can machine both internal and external threads, minimizing tool changes (except ISO / UN / NPSM / UNJ / Acme).
- NPT-focused design: Specifically optimized for NPT and related pipe-thread profiles, supporting accurate, consistent taps on threaded parts.
- 40-8NPT designation: Clear sizing and compatibility for standard NPT threading tasks.
This carbide threading insert set is engineered to deliver durable performance in demanding materials and high-speed threading. The TiAlN coating enhances hardness and wear resistance, helping maintain accuracy over longer runs and reducing tool downtime. With its versatile length and pitch options, it’s well-suited for job shops, contract manufacturers, and in-house production environments that require reliable threading across multiple standards without swapping inserts mid-operation.
| Application | Threading |
| Thread Form | NPT |
| Internal or External | Internal & External |
| Insert Size | 40 |
| Pitch | 8 |
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 40-8NPT. Click any other SKU to view its full details.
| Product SKU | Insert Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|
| 12-18NPT | 12 | 18 | £29.10 | In Stock | |
| 14-14NPT | 14 | 14 | £29.10 | In Stock | |
| 14-18NPT | 14 | 18 | £29.10 | In Stock | |
| 21-11.5NPT | 21 | 11.5 | £38.88 | In Stock | |
| 21-14NPT | 21 | 14 | £38.88 | In Stock | |
| 30-11.5NPT | 30 | 11.5 | £53.38 | In Stock | |
| 30-8NPT | 30 | 8 | £53.38 | In Stock | |
| 40-11.5NPT | 40 | 11.5 | £91.88 | 5 days | |
| 40-8NPT Viewing | 40 | 8 | £91.88 | 5 days |
No products match your filters.


