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JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - 5/16 x 18
SKU:JBO-502418
The JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - 5/16 x 18 is a precision inspection tool designed to verify external threads against the Unified UNC specification. It’s ideal for engineer...
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Specification
| Thread Form | UNC |
| Size | 5/16 |
| Pitch | 18 |
| Gauge Type | Ring Gauge (GO) |
| Thread Direction | Left Hand |
| Tolerance | 2A |
£82.80
Prices shown ex. VAT
5 days estimated lead time
— subject to availability
View Other Sizes →
Free delivery over £50 ex VAT
Secure checkout
14-day returns
30+ years expertise
Pay in 3 interest-free instalments. No extra cost if paid on time. 18+ only.
Learn more about Klarna
Learn more about Klarna
The JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - 5/16 x 18 is a precision inspection tool designed to verify external threads against the Unified UNC specification. It’s ideal for engineers, machinists, quality inspectors, and maintenance teams who need a fast, reliable way to confirm that threaded components will fit and perform as intended.
Constructed from hardened steel, this GO gauge is built for durability and wear resistance in busy shop environments. Its simple, purpose-built design supports quick insertions and clear results, helping you streamline QC workflows on production floors, in workshops, or in field service.
- Immediate Go/No-Go verification: Provides a fast, decisive check that external threads meet the specified UNC size, enabling quick pass/fail decisions without extra measurement steps.
- Rugged hardened steel construction: Delivers long service life and retains precise dimensions through repeated use, reducing tool replacement and calibration downtime.
- UNC Left-Hand 5/16 x 18 (2A) compatibility: Precisely matched to this thread form and class, ensuring you verify the exact components you manufacture or service with confidence.
Together, these features help you speed up inspections, improve consistency across batches, and reduce costly rework by delivering reliable, repeatable thread verification for UNC left-hand components at 5/16 x 18 with class 2A tolerance.
| Thread Form | UNC |
| Size | 5/16 |
| Pitch | 18 |
| Gauge Type | Ring Gauge (GO) |
| Thread Direction | Left Hand |
| Tolerance | 2A |
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.
★★★★★
Nice experience staff are very helpful and interested...
Staff are very helpful and interested in providing a good service making us the customer feel valued.
★★★★★
first place we look
honest about stock and prices are competitive.
★★★★★
Polite and helpful
Staff are very helpful and polite.Goods that were in stock were dispatched same day and back orders were quick in coming through .
★★★★★
Buying experience
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.
Full Range: JBO Thread Ring Gauges (GO) - Unified
View full collection →You are viewing JBO-502418. Click any other SKU to view its full details.
| Product SKU | Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|
| JBO-502377 | No. 1 | 64 | £114.03 | 5 days | |
| JBO-502382 | No. 2 | 56 | £86.19 | 5 days | |
| JBO-502386 | No. 3 | 48 | £103.52 | 5 days | |
| JBO-502388 | No. 4 | 40 | £75.45 | 5 days | |
| JBO-502392 | No. 5 | 40 | £69.08 | 5 days | |
| JBO-502393 | No. 6 | 32 | £58.90 | 5 days | |
| JBO-502396 | No. 8 | 32 | £55.39 | 5 days | |
| JBO-502379 | No. 10 | 24 | £54.28 | 5 days | |
| JBO-505676 | No. 12 | 24 | £63.28 | 5 days | |
| JBO-502406 | 1/4 | 20 | £51.88 | 5 days | |
| JBO-502416 | 5/16 | 18 | £55.15 | 5 days | |
| JBO-502413 | 3/8 | 16 | £60.08 | 5 days | |
| JBO-502421 | 7/16 | 14 | £65.48 | 5 days | |
| JBO-502404 | 1/2 | 13 | £71.94 | 5 days | |
| JBO-502425 | 9/16 | 12 | £99.25 | 5 days | |
| JBO-502419 | 5/8 | 11 | £84.43 | 5 days | |
| JBO-502411 | 3/4 | 10 | £104.51 | 5 days | |
| JBO-502423 | 7/8 | 9 | £127.21 | 5 days | |
| JBO-502398 | 1 | 8 | £137.06 | 5 days | |
| JBO-502401 | 1 1/8 | 7 | £183.12 | 5 days | |
| JBO-502400 | 1 1/4 | 7 | £198.46 | 5 days | |
| JBO-502403 | 1 3/8 | 6 | £213.83 | 5 days | |
| JBO-502399 | 1 1/2 | 6 | £233.56 | 5 days | |
| JBO-502402 | 1 3/4 | 5 | £292.77 | 5 days | |
| JBO-502409 | 2 | 4.5 | £335.54 | 5 days | |
| JBO-502963 | 2 1/4 | 4.5 | £382.68 | 5 days | |
| JBO-502410 | 2 1/2 | 4 | £427.63 | 5 days | |
| JBO-507588 | 2 3/4 | 4 | £476.99 | 5 days | |
| JBO-502378 | No. 1 | 64 | £167.77 | 5 days | |
| JBO-502385 | No. 2 | 56 | £128.29 | 5 days | |
| JBO-502387 | No. 3 | 48 | £135.97 | 5 days | |
| JBO-502391 | No. 4 | 40 | £105.48 | 5 days | |
| JBO-502873 | No. 5 | 40 | £96.83 | 5 days | |
| JBO-502394 | No. 6 | 32 | £82.35 | 5 days | |
| JBO-502397 | No. 8 | 32 | £77.41 | 5 days | |
| JBO-502380 | No. 10 | 24 | £77.64 | 5 days | |
| JBO-502381 | No. 12 | 24 | £82.14 | 5 days | |
| JBO-502407 | 1/4 | 20 | £76.22 | 5 days | |
| JBO-502417 | 5/16 | 18 | £81.03 | 5 days | |
| JBO-502414 | 3/8 | 16 | £88.06 | 5 days | |
| JBO-502422 | 7/16 | 14 | £98.14 | 5 days | |
| JBO-502405 | 1/2 | 13 | £107.90 | 5 days | |
| JBO-503165 | 9/16 | 12 | £120.61 | 5 days | |
| JBO-502420 | 5/8 | 11 | £128.29 | 5 days | |
| JBO-502797 | 3/4 | 10 | £156.81 | In Stock | |
| JBO-502424 | 7/8 | 9 | £189.69 | 5 days | |
| JBO-503166 | 1 | 8 | £209.44 | 5 days | |
| JBO-506400 | No. 1 | 64 | £163.39 | 5 days | |
| JBO-506401 | No. 2 | 56 | £129.40 | 5 days | |
| JBO-506402 | No. 3 | 48 | £148.02 | 5 days | |
| JBO-504041 | No. 4 | 40 | £112.95 | 5 days | |
| JBO-506403 | No. 5 | 40 | £103.52 | 5 days | |
| JBO-502395 | No. 6 | 32 | £88.15 | 5 days | |
| JBO-506404 | No. 8 | 32 | £83.11 | 5 days | |
| JBO-503427 | No. 10 | 24 | £81.36 | 5 days | |
| JBO-505677 | No. 12 | 24 | £87.84 | 5 days | |
| JBO-502408 | 1/4 | 20 | £77.76 | 5 days | |
| JBO-502418 Viewing | 5/16 | 18 | £82.80 | 5 days | |
| JBO-502415 | 3/8 | 16 | £90.25 | 5 days | |
| JBO-506405 | 7/16 | 14 | £98.14 | 5 days | |
| JBO-506406 | 1/2 | 13 | £107.90 | 5 days | |
| JBO-506407 | 9/16 | 12 | £118.42 | 5 days | |
| JBO-504042 | 5/8 | 11 | £130.48 | 5 days | |
| JBO-502412 | 3/4 | 10 | £156.81 | 5 days | |
| JBO-506408 | 7/8 | 9 | £189.69 | 5 days | |
| JBO-504043 | 1 | 8 | £209.44 | 5 days | |
| JBO-506409 | 1 1/8 | 7 | £245.62 | 5 days | |
| JBO-505756 | 1 1/4 | 7 | £268.65 | 5 days | |
| JBO-506410 | 1 3/8 | 6 | £299.34 | 5 days | |
| JBO-506411 | 1 1/2 | 6 | £317.99 | 5 days | |
| JBO-502426 | No. 1 | 72 | £126.10 | 5 days | |
| JBO-502436 | No. 2 | 64 | £105.26 | 5 days | |
| JBO-502438 | No. 3 | 56 | £104.95 | 5 days | |
| JBO-502440 | No. 4 | 48 | £92.98 | 5 days | |
| JBO-502442 | No. 5 | 44 | £74.55 | 5 days | |
| JBO-502444 | No. 6 | 40 | £71.72 | 5 days | |
| JBO-502446 | No. 8 | 36 | £66.35 | 5 days | |
| JBO-502430 | No. 10 | 32 | £52.75 | 5 days | |
| JBO-502433 | No. 12 | 28 | £63.28 | 5 days | |
| JBO-502458 | 1/4 | 28 | £51.97 | 5 days | |
| JBO-502469 | 5/16 | 24 | £55.15 | 5 days | |
| JBO-502466 | 3/8 | 24 | £60.08 | 5 days | |
| JBO-502475 | 7/16 | 20 | £64.82 | 5 days | |
| JBO-502455 | 1/2 | 20 | £71.94 | 5 days | |
| JBO-502481 | 9/16 | 18 | £77.41 | 5 days | |
| JBO-502472 | 5/8 | 18 | £85.65 | 5 days | |
| JBO-502461 | 3/4 | 16 | £99.68 | 5 days | |
| JBO-502478 | 7/8 | 14 | £117.33 | 5 days | |
| JBO-502448 | 1 | 12 | £131.59 | 5 days | |
| JBO-502453 | 1 1/8 | 12 | £148.02 | 5 days | |
| JBO-502452 | 1 1/4 | 12 | £161.19 | 5 days | |
| JBO-502454 | 1 3/8 | 12 | £175.43 | 5 days | |
| JBO-502451 | 1 1/2 | 12 | £186.41 | 5 days | |
| JBO-502427 | No. 0 | 80 | £176.54 | 5 days | |
| JBO-502429 | No. 1 | 72 | £148.02 | 5 days | |
| JBO-502437 | No. 2 | 64 | £137.06 | 5 days | |
| JBO-502439 | No. 3 | 56 | £135.97 | 5 days | |
| JBO-502441 | No. 4 | 48 | £121.72 | 5 days | |
| JBO-502443 | No. 5 | 44 | £96.83 | 5 days | |
| JBO-502445 | No. 6 | 40 | £93.10 | 5 days | |
| JBO-502447 | No. 8 | 36 | £85.65 | 5 days | |
| JBO-502431 | No. 10 | 32 | £73.58 | 5 days | |
| JBO-502435 | No. 12 | 28 | £82.14 | 5 days | |
| JBO-502459 | 1/4 | 28 | £72.81 | 5 days | |
| JBO-502470 | 5/16 | 24 | £77.10 | 5 days | |
| JBO-502467 | 3/8 | 24 | £84.22 | 5 days | |
| JBO-502476 | 7/16 | 20 | £90.46 | 5 days | |
| JBO-502456 | 1/2 | 20 | £100.55 | 5 days | |
| JBO-502482 | 9/16 | 18 | £108.45 | 5 days | |
| JBO-502473 | 5/8 | 18 | £119.52 | 5 days | |
| JBO-502463 | 3/4 | 16 | £139.25 | 5 days | |
| JBO-502479 | 7/8 | 14 | £164.47 | 5 days | |
| JBO-502449 | 1 | 12 | £183.12 | 5 days | |
| JBO-502757 | 1 1/8 | 12 | £207.25 | 5 days | |
| JBO-503207 | 1 1/4 | 12 | £225.87 | 5 days | |
| JBO-503209 | 1 3/8 | 12 | £245.62 | 5 days | |
| JBO-502768 | 1 1/2 | 12 | £264.27 | 5 days | |
| JBO-506438 | No. 0 | 80 | £176.54 | 5 days | |
| JBO-506441 | No. 1 | 72 | £148.02 | 5 days | |
| JBO-506445 | No. 2 | 64 | £137.06 | 5 days | |
| JBO-506448 | No. 3 | 56 | £135.97 | 5 days | |
| JBO-506449 | No. 4 | 48 | £121.72 | 5 days | |
| JBO-506452 | No. 5 | 44 | £96.83 | 5 days | |
| JBO-506453 | No. 6 | 40 | £93.10 | 5 days | |
| JBO-506454 | No. 8 | 36 | £85.65 | 5 days | |
| JBO-502432 | No. 10 | 32 | £76.44 | 5 days | |
| JBO-506455 | No. 12 | 28 | £83.67 | 5 days | |
| JBO-502460 | 1/4 | 28 | £72.81 | 5 days | |
| JBO-502471 | 5/16 | 24 | £81.03 | 5 days | |
| JBO-502468 | 3/8 | 24 | £84.22 | 5 days | |
| JBO-502477 | 7/16 | 20 | £92.98 | 5 days | |
| JBO-502457 | 1/2 | 20 | £104.72 | 5 days | |
| JBO-502483 | 9/16 | 18 | £116.23 | 5 days | |
| JBO-502474 | 5/8 | 18 | £119.52 | 5 days | |
| JBO-502464 | 3/4 | 16 | £139.25 | 5 days | |
| JBO-502480 | 7/8 | 14 | £164.47 | 5 days | |
| JBO-502450 | 1 | 12 | £183.12 | 5 days | |
| JBO-503127 | 1 1/8 | 12 | £207.25 | 5 days | |
| JBO-506456 | 1 1/4 | 12 | £225.87 | 5 days | |
| JBO-506457 | 1 3/8 | 12 | £245.62 | 5 days | |
| JBO-505736 | 1 1/2 | 12 | £264.27 | 5 days | |
| JBO-501299 | No. 12 | 32 | £74.79 | 5 days | |
| JBO-501313 | 1/4 | 32 | £74.79 | 5 days | |
| JBO-501326 | 5/16 | 32 | £80.16 | 5 days | |
| JBO-501323 | 3/8 | 32 | £85.20 | 5 days | |
| JBO-501329 | 7/16 | 2 | £90.46 | 5 days | |
| JBO-501310 | 1/2 | 28 | £94.52 | 5 days | |
| JBO-501334 | 9/16 | 24 | £104.60 | 5 days | |
| JBO-501327 | 5/8 | 24 | £111.84 | 5 days | |
| JBO-501316 | 11/16 | 24 | £120.61 | 5 days | |
| JBO-501319 | 3/4 | 20 | £127.21 | 5 days | |
| JBO-501317 | 13/16 | 20 | £133.78 | 5 days | |
| JBO-501333 | 7/8 | 20 | £144.74 | 5 days | |
| JBO-501318 | 15/16 | 20 | £155.70 | 5 days | |
| JBO-501300 | 1 | 20 | £163.39 | 5 days | |
| JBO-501305 | 1 1/16 | 18 | £173.24 | 5 days | |
| JBO-501303 | 1 1/8 | 18 | £179.84 | 5 days | |
| JBO-501307 | 1 3/16 | 18 | £189.69 | 5 days | |
| JBO-501302 | 1 1/4 | 18 | £202.87 | 5 days | |
| JBO-501308 | 1 5/16 | 18 | £213.83 | 5 days | |
| JBO-501306 | 1 3/8 | 18 | £225.87 | 5 days | |
| JBO-501309 | 1 7/16 | 18 | £236.85 | 5 days | |
| JBO-501301 | 1 1/2 | 18 | £248.90 | 5 days | |
| JBO-506769 | 1 9/16 | 18 | £266.46 | 5 days | |
| JBO-506489 | No. 12 | 32 | £105.71 | 5 days | |
| JBO-501315 | 1/4 | 32 | £105.71 | 5 days | |
| JBO-506490 | 5/16 | 32 | £116.23 | 5 days | |
| JBO-506491 | 3/8 | 32 | £121.72 | 5 days | |
| JBO-501332 | 7/16 | 2 | £127.21 | 5 days | |
| JBO-503778 | 1/2 | 28 | £133.78 | 5 days | |
| JBO-505871 | 9/16 | 24 | £145.83 | 5 days | |
| JBO-503138 | 5/8 | 24 | £167.77 | 5 days | |
| JBO-506492 | 11/16 | 24 | £178.73 | 5 days | |
| JBO-501322 | 3/4 | 20 | £188.61 | 5 days | |
| JBO-506493 | 13/16 | 20 | £202.87 | 5 days | |
| JBO-506494 | 7/8 | 20 | £218.21 | 5 days | |
| JBO-506495 | 15/16 | 20 | £233.56 | 5 days | |
| JBO-504056 | 1 | 20 | £244.52 | 5 days | |
| JBO-502570 | 1/4 | 36 | £207.25 | 5 days | |
| JBO-502546 | 1 | 32 | £421.06 | 5 days | |
| JBO-502576 | 11/16 | 16 | £350.89 | 5 days | |
| JBO-502580 | 13/16 | 16 | £307.02 | 5 days | |
| JBO-502601 | 7/8 | 16 | £313.60 | 5 days | |
| JBO-502545 | 1 | 16 | £350.89 | 5 days | |
| JBO-542688 | 1 1/16 | 16 | £370.62 | 5 days | |
| JBO-502561 | 1 3/16 | 16 | £407.90 | 5 days | |
| JBO-505372 | 1 | 14 | £288.38 | 5 days | |
| JBO-502552 | 1 1/16 | 12 | £321.28 | 5 days | |
| JBO-502560 | 1 3/16 | 12 | £364.04 | 5 days | |
| JBO-502563 | 1 5/16 | 12 | £359.66 | 5 days | |
| JBO-502562 | 1 5/8 | 12 | £459.45 | 5 days | |
| JBO-502554 | 1 3/4 | 12 | £441.89 | 5 days | |
| JBO-502565 | 1 7/8 | 12 | £482.48 | 5 days | |
| JBO-502584 | 2 | 12 | £490.14 | 5 days | |
| JBO-503417 | 1 1/8 | 8 | £357.46 | 5 days | |
| JBO-502549 | 1 1/4 | 8 | £359.66 | 5 days | |
| JBO-552099 | 1 3/8 | 8 | £387.07 | 5 days | |
| JBO-502547 | 1 1/2 | 8 | £463.83 | 5 days | |
| JBO-502924 | 1 5/8 | 8 | £486.86 | 5 days | |
| JBO-502556 | 1 3/4 | 8 | £552.65 | 5 days | |
| JBO-503356 | 2 | 8 | £596.51 | 5 days | |
| JBO-504210 | No. 2 | 56 | £167.77 | 5 days | |
| JBO-503593 | No. 4 | 40 | £139.25 | 5 days | |
| JBO-505569 | No. 6 | 32 | £120.61 | 5 days | |
| JBO-501415 | No. 8 | 32 | £111.84 | 5 days | |
| JBO-547026 | No. 10 | 24 | £111.84 | 5 days | |
| JBO-547027 | 1/4 | 20 | £111.84 | 5 days | |
| JBO-547028 | 5/16 | 18 | £111.84 | 5 days | |
| JBO-507449 | 3/8 | 16 | £116.23 | 5 days | |
| JBO-554996 | 7/16 | 14 | £148.02 | 5 days | |
| JBO-547029 | No. 4 | 48 | £143.64 | 5 days | |
| JBO-505347 | No. 6 | 40 | £117.33 | 5 days | |
| JBO-501418 | No. 8 | 36 | £108.02 | 5 days | |
| JBO-501417 | No. 10 | 32 | £94.30 | 5 days | |
| JBO-504244 | No. 12 | 28 | £108.02 | 5 days | |
| JBO-501419 | 1/4 | 28 | £94.30 | 5 days | |
| JBO-501422 | 5/16 | 24 | £98.80 | 5 days | |
| JBO-501421 | 3/8 | 24 | £106.58 | 5 days | |
| JBO-501424 | 7/16 | 20 | £116.23 | 5 days | |
| JBO-502986 | 1/2 | 20 | £128.29 | 5 days | |
| JBO-501425 | 9/16 | 18 | £135.97 | 5 days | |
| JBO-501423 | 5/8 | 18 | £153.51 | 5 days | |
| JBO-501420 | 3/4 | 16 | £176.54 | 5 days | |
| JBO-503651 | 7/8 | 14 | £207.25 | 5 days | |
| JBO-503703 | 1 | 12 | £233.56 | 5 days | |
| JBO-547575 | 1/4 | 28 | £151.32 | 5 days | |
| JBO-503866 | 3/8 | 24 | £171.05 | 5 days | |
| JBO-547590 | 1/2 | 20 | £206.14 | 5 days |
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