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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 |
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Description
The Robert Charles Piloted Microstop Countersink is a precision tool designed for high-accuracy countersinking with an integral pilot. It features a 21 mm cutter diameter and a 3/8" pilot diameter, plus a 100° countersink angle, making it well-suited for aerospace, automotive, and other precision engineering applications. The 3‑flute cutting design ensures efficient material removal and a clean finish, even in challenging workpieces.
Designed to work with microstop cages, the threaded shank provides a secure fit and reliable depth control, helping you maintain consistent results across batches. The pilot diameter is held to tight tolerances (-0.0005" to -0.0015"), delivering repeatable alignment and precise countersink depth every time.
- Precision 3‑Flute Cutting Design: Delivers clean, controlled countersinking with efficient chip evacuation for fast, reliable production.
- Integral Pilot for Accurate Hole Alignment: Keeps the countersink centered in the hole, reducing drift and ensuring consistent depth across parts.
- Threaded Shank with Microstop Cage Compatibility: Ensures a secure fit and stable depth control in microstop setups, minimizing setup time and chatter.
This combination of precise geometry, tight pilot tolerances, and robust mounting makes the tool a dependable choice for technicians and engineers seeking repeatable, high-quality countersinking results in demanding manufacturing environments.
Part Numbers
- Protool Part Number
- S9.52-100-21
- Brand
- Robert Charles
- Category
- Countersinks
Need cutting data? Call 01732 887334 or email sales@protool-ltd.co.uk.
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.
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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