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Carmex Single Threading Insert holder - For Carbide External/Internal Threading Inserts - SR0018H21

SKU:SR0018H21

The Carmex Single Threading Insert Holder SR0018H21 is a precision tool holder engineered for CNC milling threading applications. It supports carbide external and internal threading inserts, help... Read more ↓
Insert Size21
Shank Diameter20
Shank MaterialSteel
Reach30
Overall Length85
Minimum Bore Diameter18
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£121.04
Prices shown ex. VAT
5 days estimated lead time — subject to availability
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The Carmex Single Threading Insert Holder SR0018H21 is a precision tool holder engineered for CNC milling threading applications. It supports carbide external and internal threading inserts, helping engineers, machinists, and hobbyists produce accurate, repeatable threads with minimal setup.

As part of the Mill-Thread family, this holder is designed to enable high-speed threading through helix interpolation and multi-tooth carbide inserts. It delivers productive results with lower tooling costs compared with traditional taps and dies. Important compatibility notes: SR0018H21 is incompatible with inserts 21 I 3.5 ISO, 21 I 8 UN, 21 I 7 UN, 21-11 BSPT, 21-11.5 NPT, and 21-11.5 NPTF.

  • Internal coolant bore for clean, controlled cutting: Delivers coolant directly to the cutting edge to improve chip evacuation, reduce heat buildup, and extend insert life during threading on CNC mills.
  • Optimized for Mill-Thread carbide inserts: Works with multi-tooth carbide inserts to enable fast, reliable threading through helix interpolation, delivering consistent thread quality across a range of materials.
  • Cost-efficient threading solution: A modular holder with replaceable inserts that lowers tooling costs compared with taps and dies, while simplifying maintenance and reducing downtime.

Pairing this holder with compatible carbide inserts gives you a dependable, repeatable threading process that helps you tighten production schedules, improve finish quality, and lower overall production costs. The design supports quick insert changes to keep your workflow moving and your results consistent.

Insert Size 21
Shank Diameter 20
Shank Material Steel
Reach 30
Overall Length 85
Minimum Bore Diameter 18
Flutes 1
Neck Diameter 14.4
Insert Screw S21
Torx Key K21
Extension N/A

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.

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Staff are very helpful and polite.Goods that were in stock were dispatched same day and back orders were quick in coming through .
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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.
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Full Range: Carmex Single Threading Insert holders - For Carbide External/Internal Threading Inserts

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You are viewing SR0018H21. Click any other SKU to view its full details.

Product SKUInsert SizeShank DiameterReachOverall LengthMinimum Bore DiameterNeck DiameterPriceStock Order
SR0009H12 122014859.57.5£91.20 5 days
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SR0017H14 142030851713.4£98.02 5 days
SR0018H21 Viewing212030851814.4£121.04 5 days
SR0021H21 212040942116.5£127.84 In Stock
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