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Robert Charles Plain Shank Counterbore M35-HSS-E 5% Cobalt - 5/16 Cap Screw Size - 0.312 Pilot Size
| Cap Screw Size | 5/16 |
| Pilot Size | 0.312 |
| Cutting Diameter | 0.475 |
| Shank Size | 3/8 |
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Description
The Robert Charles Plain Shank Counterbore is a high-performance cutting tool designed for precision counterboring in metalworking. Built from M35 HSS-E with 5% cobalt, it delivers exceptional heat resistance, wear life, and cutting performance for engineers, machinists, and automotive professionals who demand dependable results.
- Material: M35 HSS‑E with 5% cobalt, delivering enhanced heat resistance and wear resistance for longer tool life in demanding metals.
- Shank Type: Plain shank for straightforward fitment in standard tool holders, ensuring stable, repeatable machining.
- Pilot Size: 0.312 inch pilot to guide the bore with precision and maintain alignment throughout the cut.
- Cap Screw Size: 5/16 cap screw compatibility for secure installation in appropriate tooling setups.
- Counterbore Geometry: Optimized cutting edges and flute geometry for clean, square counterbores and consistent bottom finishes.
- Applications: Suited to precision engineering, automotive manufacturing, and general workshop use where durability and reliability matter.
With its cobalt-enhanced alloy and a plain shank designed for standard holders, this counterbore supports repeatable depth control and smooth chip flow, reducing heat buildup and wear during extended operation. The 0.312 inch pilot fosters accurate bore guidance, while the 5/16 cap screw sizing ensures quick, secure setup. For practitioners performing high-tolerance assemblies or precision pocket counters, this tool delivers dependable performance, helping streamline workflows and reduce rework in metal fabrication and repair environments.
Part Numbers
- Protool Part Number
- 5770-5/16-CLOSE FIT
- Brand
- Robert Charles
- Category
- Counterbore
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 Plain Shank Counterbores M35-HSS-E 5% Cobalt
View full collection →You are viewing 5770-5/16-CLOSE FIT. Click any other SKU to view its full details.
| Product SKU | Cap Screw Size | Pilot Size | Cutting Diameter | Shank Size | Overall Length | Price | Stock | Order |
|---|---|---|---|---|---|---|---|---|
| 5770-4-CLOSE FIT | #4 | 0.112 | 0.186 | 5/32 | 3 | £33.97 | 2-3 days | |
| 5770-4-1/64 OVER | #4 | 0.127 | 0.202 | 5/32 | 3 | £33.97 | 2-3 days | |
| 5770-4-1/32 OVER | #4 | 0.143 | 0.217 | 5/32 | 3 | £33.97 | 2-3 days | |
| 5770-5-CLOSE FIT | #5 | 0.125 | 0.205 | 3/16 | 3 | £34.76 | 2-3 days | |
| 5770-5-1/64 OVER | #5 | 0.140 | 0.221 | 3/16 | 3 | £34.76 | 2-3 days | |
| 5770-5-1/32 OVER | #5 | 0.156 | 0.237 | 3/16 | 3 | £34.76 | 2-3 days | |
| 5770-6-CLOSE FIT | #6 | 0.138 | 0.228 | 7/32 | 3 | £34.76 | 2-3 days | |
| 5770-6-1/64 OVER | #6 | 0.153 | 0.244 | 7/32 | 3 | £34.76 | 2-3 days | |
| 5770-6-1/32 OVER | #6 | 0.169 | 0.260 | 7/32 | 3 | £34.76 | 2-3 days | |
| 5770-8-CLOSE FIT | #8 | 0.164 | 0.272 | 1/4 | 3 | £35.55 | 2-3 days | |
| 5770-8-1/64 OVER | #8 | 0.179 | 0.288 | 1/4 | 3 | £35.55 | 2-3 days | |
| 5770-8-1/32 OVER | #8 | 0.195 | 0.304 | 1/4 | 3 | £35.55 | 2-3 days | |
| 570-10-CLOSE FIT | #10 | 0.19 | 0.314 | 9/32 | 4.5 | £37.92 | 2-3 days | |
| 5770-10-1/64 OVER | #10 | 0.205 | 0.33 | 9/32 | 4.5 | £37.92 | 2-3 days | |
| 5770-10-1/32 OVER | #10 | 0.221 | 0.346 | 9/32 | 4.5 | £37.92 | 2-3 days | |
| 5770-1/4-CLOSE FIT | 1/4 | 0.25 | 0.382 | 5/16 | 4.5 | £41.87 | 2-3 days | |
| 5770-1/4-1/64 OVER | 1/4 | 0.265 | 0.398 | 5/16 | 4.5 | £41.87 | 2-3 days | |
| 5770-1/4-1/32 OVER | 1/4 | 0.281 | 0.414 | 5/16 | 4.5 | £41.87 | 2-3 days | |
| 5770-5/16-CLOSE FIT Viewing | 5/16 | 0.312 | 0.475 | 3/8 | 4.5 | £47.40 | 2-3 days | |
| 5770-5/16-1/64 OVER | 5/16 | 0.328 | 0.491 | 3/8 | 4.5 | £47.40 | 2-3 days | |
| 5770-5/16-1/32 OVER | 5/16 | 0.343 | 0.507 | 3/8 | 4.5 | £47.40 | 2-3 days | |
| 5770-3/8-CLOSE FIT | 3/8 | 0.375 | 0.572 | 1/2 | 5 | £63.99 | 2-3 days | |
| 5770-3/8-1/64 OVER | 3/8 | 0.39 | 0.588 | 1/2 | 5 | £63.99 | 2-3 days | |
| 5770-3/8-1/32 OVER | 3/8 | 0.406 | 0.604 | 1/2 | 5 | £63.99 | 2-3 days | |
| 5770-7/16-CLOSE FIT | 7/16 | 0.437 | 0.663 | 1/2 | 5 | £85.32 | 2-3 days | |
| 5770-7/16-1/64 OVER | 7/16 | 0.452 | 0.679 | 1/2 | 5 | £85.32 | 2-3 days | |
| 5770-7/16-1/32 OVER | 7/16 | 0.468 | 0.695 | 1/2 | 5 | £85.32 | 2-3 days | |
| 5770-1/2-CLOSE FIT | 1/2 | 0.5 | 0.757 | 1/2 | 6 | £109.02 | 2-3 days | |
| 5770-1/2-1/64 OVER | 1/2 | 0.515 | 0.773 | 1/2 | 6 | £109.02 | 2-3 days | |
| 5770-1/2-1/32 OVER | 1/2 | 0.531 | 0.789 | 1/2 | 6 | £109.02 | 2-3 days | |
| 5770-5/8-1/64 OVER | 5/8 | 0.641 | 0.961 | 5/8 | 6 | £142.20 | 2-3 days | |
| 5770-5/8-CLOSE FIT | 5/8 | 0.625 | 0.945 | 5/8 | 6 | £142.20 | 2-3 days | |
| 5770-5/8-1/32 OVER | 5/8 | 0.656 | 0.977 | 5/8 | 6 | £142.20 | 2-3 days | |
| 5770-3/4-CLOSE FIT | 3/4 | 0.766 | 1.187 | 3/4 | 7 | £211.72 | 2-3 days | |
| 5770-3/4-1/32 OVER | 3/4 | 0.781 | 1.203 | 3/4 | 7 | £211.72 | 2-3 days | |
| 5770-7/8-CLOSE FIT | 7/8 | 0.891 | 1.375 | 7/8 | 7 | £255.96 | 2-3 days | |
| 5770-7/8-1/32 OVER | 7/8 | 0.906 | 1.391 | 7/8 | 7 | £255.96 | 2-3 days |
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