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16EL12UNK20 - Carmex Thread Turning External Insert - UN (UNC,UNF,UNEF,UNS) - Left Hand
| Thread Type | External |
| Thread Direction | Left Hand |
| Thread Form | UN (UNC UNF UNEF UNS) |
| Pitch | 12 |
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Introducing Carmex Thread Turning External Insert 16EL12UNK20 — a triangular, laydown insert engineered to cut external threads to UN standards (UNC, UNF, UNEF, UNS) with a left-hand orientation. This versatile tool is ideal for machinists, engineers, and maintenance teams who need reliable performance across a broad range of thread types in a single, durable solution. Its robust carbide composition and optimized geometry help deliver consistent, repeatable threads from basic to demanding applications.
- Broad UN thread compatibility: One insert covers UNC, UNF, UNEF, and UNS external threads, reducing tool changes and simplifying inventory while preserving accuracy across multiple thread forms.
- Left-hand threading performance: Specifically designed for left-handed threads, providing smooth cutting action, stable chip flow, and predictable results in production or repair work.
- Durable carbide with precision geometry: Hardened carbide with optimized rake and edge geometry for long life, better finish, and lower rework on a wide range of materials.
This insert helps you streamline tooling, minimize downtime, and consistently produce high-quality thread profiles. With Carmex, you get dependable performance from a supplier trusted by professionals for tough threading tasks—across shops, job sites, and maintenance bays.
Part Numbers
- Protool Part Number
- 16EL12UNK20
- Brand
- Carmex
- Category
- Thread Turning
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.



