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

Carmex Carbide Threading Insert - UNJ - TiAlN Coated - 21I16UNJ

SKU:21I16UNJ

The Carmex Carbide Threading Insert - UNJ - TiAlN Coated (21I16UNJ) is a versatile threading solution designed for machinists who work with a wide range of thread profiles. Built to perform in bot... Read more ↓
P
M
K
N
S
ApplicationThreading
Thread FormUNJ
Internal or ExternalInternal
Insert Size21
Pitch16
Download Cutting Data
£43.03
Prices shown ex. VAT
5 days estimated lead time — subject to availability
View Other Sizes →
Free delivery over £50 ex VAT
Secure checkout
14-day returns
30+ years expertise
Klarna
Pay in 3 interest-free instalments. No extra cost if paid on time. 18+ only.
Learn more about Klarna
Speak to our team
01732 887334
Mon – Thurs 8:30 – 17:30 · Fri 8:30 – 16:30

The Carmex Carbide Threading Insert - UNJ - TiAlN Coated (21I16UNJ) is a versatile threading solution designed for machinists who work with a wide range of thread profiles. Built to perform in both internal and external threading tasks, it delivers dependable, precision results across multiple applications.

  • Thread profile coverage: A versatile collection of inserts that covers all common thread profiles, reducing the need for multiple tools.
  • Length options: Five lengths spanning from 12 mm up to 40 mm to match different depths and pitches.
  • Pitch range: Capable of handling pitches from 0.5 mm / 32 TPI to 6.0 mm / 4 TPI.
  • Double-sided cutting edges: Each insert has two cutting edges for extended wear life (note exceptions for BSPT/NPT/NPTF/American Buttress/API RD).
  • Internal/external capability: For many thread profiles, the same insert can machine both internal and external threads (exceptions for ISO/UN/NPSM/UNJ/Acme).
  • Coating: TiAlN coating enhances wear resistance and heat tolerance for longer insert life in demanding materials.
  • Material: Carbide substrate delivers rigidity, precision, and reliable performance in threading operations.

With this insert, you gain a streamlined, economical tool that supports a broad range of thread forms without swapping to multiple inserts. The double-edged design minimizes downtime by enabling reuse across cuts, while the TiAlN coating helps maintain a sharp edge in higher-temperature work. Ideal for job shops and production environments, it simplifies tooling inventories, speeds setup, and delivers consistent thread quality across UNJ and other common profiles.

Application Threading
Thread Form UNJ
Internal or External Internal
Insert Size 21
Pitch 16

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.

★★★★★
Nice experience staff are very helpful and interested...
Staff are very helpful and interested in providing a good service making us the customer feel valued.
Bill
★★★★★
first place we look
honest about stock and prices are competitive.
Phil
★★★★★
Polite and helpful
Staff are very helpful and polite.Goods that were in stock were dispatched same day and back orders were quick in coming through .
Graham
★★★★★
Buying experience
Phone requests are handled quickly and without any fuss. The website is easy to use and straightforward to order from. It’s especially helpful that it shows real‑time availability, so we don’t need to call to confirm whether parts will arrive.
Jeremy

Full Range: Carmex Carbide Threading Inserts - UNJ - TiAlN Coated

View full collection →

You are viewing 21I16UNJ. Click any other SKU to view its full details.

Product SKUInsert SizePitchPriceStock Order
14I24UNJ 1424£32.37 5 days
14E24UNJ 1424£32.37 5 days
14I20UNJ 1420£32.37 5 days
14E20UNJ 1420£32.37 5 days
14I18UNJ 1418£26.50 In Stock
14E18UNJ 1418£32.37 5 days
14I16UNJ 1416£32.37 5 days
14E16UNJ 1416£32.37 5 days
14I14UNJ 1414£32.37 5 days
14E14UNJ 1414£32.37 5 days
14I12UNJ 1412£32.37 5 days
14E12UNJ 1412£32.37 5 days
21I24UNJ 2124£43.03 5 days
21E24UNJ 2124£43.03 5 days
21I20UNJ 2120£43.03 5 days
21E20UNJ 2120£43.03 5 days
21I18UNJ 2118£43.03 5 days
21E18UNJ 2118£43.03 5 days
21I16UNJ Viewing2116£43.03 5 days
21E16UNJ 2116£43.03 5 days
21I14UNJ 2114£43.03 5 days
21E14UNJ 2114£43.03 5 days
21I12UNJ 2112£35.22 In Stock
21E12UNJ 2112£43.03 5 days

Complete Your Project

with tools we think you'll like