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Carmex Single Threading Insert holder - For Carbide External/Internal Threading Inserts - SR0018H21
| Insert Size | 21 |
| Shank Diameter | 20 |
| Shank Material | Steel |
| Reach | 30 |
| Overall Length | 85 |
| Minimum Bore Diameter | 18 |
Learn more about Klarna
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.
Full Range: Carmex Single Threading Insert holders - For Carbide External/Internal Threading Inserts
View full collection →You are viewing SR0018H21. Click any other SKU to view its full details.
| Product SKU | Insert Size | Shank Diameter | Reach | Overall Length | Minimum Bore Diameter | Neck Diameter | Price | Stock | Order |
|---|---|---|---|---|---|---|---|---|---|
| SR0009H12 | 12 | 20 | 14 | 85 | 9.5 | 7.5 | £91.20 | 5 days | |
| SR0010H12 | 12 | 20 | 16 | 85 | 9.9 | 7.6 | £100.72 | 5 days | |
| SR0012F14 | 14 | 20 | 20 | 75 | 12 | 8.9 | £79.68 | 5 days | |
| SR0014H14 | 14 | 20 | 25 | 85 | 14.5 | 11.2 | £87.62 | 5 days | |
| SR0017H14 | 14 | 20 | 30 | 85 | 17 | 13.4 | £98.02 | 5 days | |
| SR0018H21 Viewing | 21 | 20 | 30 | 85 | 18 | 14.4 | £121.04 | 5 days | |
| SR0021H21 | 21 | 20 | 40 | 94 | 21 | 16.5 | £127.84 | In Stock | |
| SR0029J30 | 30 | 25 | 50 | 110 | 29 | 22.4 | £156.08 | 5 days | |
| SR0048M40 | 40 | 40 | 78 | 153 | 48 | 35 | £212.46 | 5 days |
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