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Robert Charles Piloted Microstop Countersink - 3 Flute - Integral Pilot - Threaded Shank - 21mm Cutter Dia - 3/8 Pilot Diameter - 100°
| Pilot Diameter | 3/8 |
| Cutter Diameter | 21 |
| Inclusive Angle | 100 |
| Thread | M8X1 |
| Radius Between Pilot & Flute | 0.035 - 0.040 |
Learn more about Klarna
The Robert Charles Piloted Microstop Countersink features a precision 3-flute cutting design with an integral pilot for accurate hole alignment and consistent countersinking. Designed for use with microstop cages, the threaded shank provides secure fitment and reliable depth control. Manufactured to tight tolerances, the pilot diameter is held to −0.0005" to −0.0015", making it ideal for high-accuracy aerospace, automotive, and precision engineering applications.
| Pilot Diameter | 3/8 |
| Cutter Diameter | 21 |
| Inclusive Angle | 100 |
| Thread | M8X1 |
| Radius Between Pilot & Flute | 0.035 - 0.040 |
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: Robert Charles Piloted Microstop Countersink - 3 Flute - Integral Pilot - Threaded Shank
View full collection →You are viewing S9.52-100-21. Click any other SKU to view its full details.
| Product SKU | Pilot Diameter | Cutter Diameter | Inclusive Angle | Thread | Radius Between Pilot & Flute | Price | Stock | Order |
|---|---|---|---|---|---|---|---|---|
| S2.38-90-10 | 3/32 | 10 | 90 | M6X1 | 0.010 - 0.015 | £59.25 | 2-3 days | |
| S3.17-090-10 | 1/8 | 10 | 90 | M6X1 | 0.015 - 0.020 | £59.25 | 2-3 days | |
| S3.96-90-10 | 5/32 | 10 | 90 | M6X1 | 0.020 - 0.025 | £59.25 | 2-3 days | |
| S4.76-90-10 | 3/16 | 10 | 90 | M6X1 | 0.020 - 0.025 | £59.25 | 2-3 days | |
| S4.76-90-14 | 3/16 | 14 | 90 | M8X1 | 0.025 - 0.030 | £63.99 | 2-3 days | |
| S6.35-90-14 | 1/4 | 14 | 90 | M8X1 | 0.025 - 0.030 | £63.99 | 2-3 days | |
| S7.94-90-17 | 5/16 | 17 | 90 | M8X1 | 0.035 - 0.040 | £102.70 | 2-3 days | |
| S9.52-90-21 | 3/8 | 21 | 90 | M8X1 | 0.035 - 0.040 | £107.44 | 2-3 days | |
| S2.38-100-10 | 3/32 | 10 | 100 | M6X1 | 0.010 - 0.015 | £37.92 | 2-3 days | |
| S3.17-100-10 | 1/8 | 10 | 100 | M6X1 | 0.015 - 0.020 | £37.92 | 2-3 days | |
| S3.96-100-10 | 5/32 | 10 | 100 | M6X1 | 0.020 - 0.025 | £37.92 | 2-3 days | |
| S4.76-100-10 | 3/16 | 10 | 100 | M6X1 | 0.020 - 0.025 | £37.92 | 2-3 days | |
| S4.76-100-14 | 3/16 | 14 | 100 | M8X1 | 0.025 - 0.030 | £45.82 | 2-3 days | |
| S6.35-100-14 | 1/4 | 14 | 100 | M8X1 | 0.025 - 0.030 | £45.82 | 2-3 days | |
| S7.94-100-17 | 5/16 | 17 | 100 | M8X1 | 0.035 - 0.040 | £65.57 | 2-3 days | |
| S9.52-100-21 Viewing | 3/8 | 21 | 100 | M8X1 | 0.035 - 0.040 | £69.52 | 2-3 days | |
| S2.38-120-10 | 3/32 | 10 | 120 | M6X1 | 0.010 - 0.015 | £60.04 | 2-3 days | |
| S3.17-120-10 | 1/8 | 10 | 120 | M6X1 | 0.015 - 0.020 | £60.04 | 2-3 days | |
| S3.96-120-10 | 5/32 | 10 | 120 | M6X1 | 0.020 - 0.025 | £60.04 | 2-3 days | |
| S4.76-120-10 | 3/16 | 10 | 120 | M6X1 | 0.020 - 0.025 | £60.04 | 2-3 days | |
| S4.76-120-14 | 3/16 | 14 | 120 | M8X1 | 0.025 - 0.030 | £63.20 | 2-3 days | |
| S6.35-120-14 | 1/4 | 14 | 120 | M8X1 | 0.025 - 0.030 | £63.20 | 2-3 days | |
| S7.94-120-17 | 5/16 | 17 | 120 | M8X1 | 0.035 - 0.040 | £102.70 | 2-3 days | |
| S9.52-120-21 | 3/8 | 21 | 120 | M8X1 | 0.035 - 0.040 | £107.44 | 2-3 days |
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