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JBO Thread Plug Gauge - UNC Go-No/Go - Right Hand - 2B - 1/4 x 20
SKU:JBO-512403
The JBO UNC Go-No/Go Thread Plug Gauge is a precision inspection tool designed to verify internal threads in holes and housings that use 1/4-20 UNC right-hand threads with class 2B tolerance. It’...
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Specification
| Thread Form | UNC |
| Size | 1/4 |
| Pitch | 20 |
| Gauge Type | Plug Gauge (D/E) |
| Thread Direction | Right Hand |
| Tolerance | 2B |
£62.41
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 UNC Go-No/Go Thread Plug Gauge is a precision inspection tool designed to verify internal threads in holes and housings that use 1/4-20 UNC right-hand threads with class 2B tolerance. It’s ideal for manufacturing, automotive, and aerospace quality teams that need fast, reliable go/no-go checks to confirm thread acceptance or rejection.
Designed with a sturdy two-ended, knurled body, this compact gauge provides easy handling in tight spaces and lets technicians perform Go (conforming) and No-Go (non-conforming) checks without removing the gauge from the workpiece. It’s machined to tight Unified thread standards, ensuring consistent results across batches and over time.
- Go/No-Go quick checks: The two ends are sized for 1/4-20 UNC right-hand threads, enabling immediate pass/fail decisions to verify proper thread fit and prevent incorrect assemblies.
- Precise, repeatable measurements: Built to exact thread standards with 2B class tolerance, delivering consistent results across operators and production runs.
- Durable, user-friendly construction: Rugged design with a knurled grip and dual ends for easy handling in busy shop environments, designed for reliable use day after day.
Using the JBO Thread Plug Gauge helps you speed up thread verification, reduce rework, and improve confidence in threaded assemblies. It supports tighter quality control, smoother workflows, and better overall performance in your manufacturing or maintenance processes.
| Thread Form | UNC |
| Size | 1/4 |
| Pitch | 20 |
| Gauge Type | Plug Gauge (D/E) |
| Thread Direction | Right Hand |
| Tolerance | 2B |
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 Plug Gauges - Unified Go-No/Go
View full collection →You are viewing JBO-512403. Click any other SKU to view its full details.
| Product SKU | Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|
| JBO-512363 | No. 1 | 64 | £127.21 | 5 days | |
| JBO-512368 | No. 2 | 56 | £96.83 | 5 days | |
| JBO-512373 | No. 3 | 48 | £96.83 | 5 days | |
| JBO-512375 | No. 4 | 40 | £82.24 | In Stock | |
| JBO-512382 | No. 5 | 40 | £82.24 | 5 days | |
| JBO-512384 | No. 6 | 32 | £68.99 | 5 days | |
| JBO-512389 | No. 8 | 32 | £65.36 | 5 days | |
| JBO-512365 | No. 10 | 24 | £63.94 | 5 days | |
| JBO-512367 | No. 12 | 24 | £69.30 | 5 days | |
| JBO-512403 Viewing | 1/4 | 20 | £62.41 | 5 days | |
| JBO-512410 | 5/16 | 18 | £62.41 | 5 days | |
| JBO-512408 | 3/8 | 16 | £64.37 | 5 days | |
| JBO-512415 | 7/16 | 14 | £69.74 | 5 days | |
| JBO-512401 | 1/2 | 13 | £71.61 | 5 days | |
| JBO-512419 | 9/16 | 12 | £77.54 | 5 days | |
| JBO-512413 | 5/8 | 11 | £79.83 | 5 days | |
| JBO-512406 | 3/4 | 10 | £91.24 | 5 days | |
| JBO-512417 | 7/8 | 9 | £106.04 | 5 days | |
| JBO-512392 | 1 | 8 | £119.52 | 5 days | |
| JBO-512398 | 1 1/8 | 7 | £133.78 | 5 days | |
| JBO-512396 | 1 1/4 | 7 | £145.83 | 5 days | |
| JBO-512399 | 1 3/8 | 6 | £169.96 | 5 days | |
| JBO-512394 | 1 1/2 | 6 | £187.50 | 5 days | |
| JBO-512364 | No. 1 | 64 | £166.67 | 5 days | |
| JBO-512369 | No. 2 | 56 | £124.99 | 5 days | |
| JBO-512374 | No. 3 | 48 | £124.99 | 5 days | |
| JBO-512377 | No. 4 | 40 | £106.58 | 5 days | |
| JBO-512383 | No. 5 | 40 | £106.58 | 5 days | |
| JBO-512386 | No. 6 | 32 | £89.16 | 5 days | |
| JBO-512390 | No. 8 | 32 | £84.43 | 5 days | |
| JBO-512366 | No. 10 | 24 | £83.01 | 5 days | |
| JBO-516808 | No. 12 | 24 | £89.69 | 5 days | |
| JBO-512404 | 1/4 | 20 | £82.02 | 5 days | |
| JBO-512412 | 5/16 | 18 | £82.02 | 5 days | |
| JBO-513092 | 3/8 | 16 | £84.22 | 5 days | |
| JBO-512416 | 7/16 | 14 | £90.70 | 5 days | |
| JBO-512402 | 1/2 | 13 | £93.76 | 5 days | |
| JBO-512420 | 9/16 | 12 | £100.67 | 5 days | |
| JBO-512414 | 5/8 | 11 | £104.82 | 5 days | |
| JBO-512407 | 3/4 | 10 | £119.52 | 5 days | |
| JBO-512418 | 7/8 | 9 | £137.06 | 5 days | |
| JBO-512393 | 1 | 8 | £155.70 | 5 days | |
| JBO-517324 | No. 1 | 64 | £183.12 | 5 days | |
| JBO-517325 | No. 2 | 56 | £139.25 | 5 days | |
| JBO-517326 | No. 3 | 48 | £139.25 | 5 days | |
| JBO-514701 | No. 4 | 40 | £118.42 | 5 days | |
| JBO-517327 | No. 5 | 40 | £118.42 | 5 days | |
| JBO-514702 | No. 6 | 32 | £99.13 | 5 days | |
| JBO-514703 | No. 8 | 32 | £94.09 | 5 days | |
| JBO-514070 | No. 10 | 24 | £92.44 | 5 days | |
| JBO-517328 | No. 12 | 24 | £99.68 | 5 days | |
| JBO-512405 | 1/4 | 20 | £91.01 | 5 days | |
| JBO-517329 | 5/16 | 18 | £91.01 | 5 days | |
| JBO-512409 | 3/8 | 16 | £93.64 | 5 days | |
| JBO-517330 | 7/16 | 14 | £100.67 | 5 days | |
| JBO-516810 | 1/2 | 13 | £104.29 | 5 days | |
| JBO-517331 | 9/16 | 12 | £111.84 | 5 days | |
| JBO-517332 | 5/8 | 11 | £116.23 | 5 days | |
| JBO-514704 | 3/4 | 10 | £131.59 | 5 days | |
| JBO-517333 | 7/8 | 9 | £153.51 | 5 days | |
| JBO-514705 | 1 | 8 | £172.16 | 5 days | |
| JBO-517334 | 1 1/8 | 7 | £196.27 | 5 days | |
| JBO-517335 | 1 1/4 | 7 | £209.44 | 5 days | |
| JBO-517336 | 1 3/8 | 6 | £244.52 | 5 days | |
| JBO-517337 | 1 1/2 | 6 | £273.04 | 5 days | |
| JBO-512421 | No. 0 | 80 | £120.61 | 5 days | |
| JBO-512424 | No. 1 | 72 | £106.37 | 5 days | |
| JBO-512432 | No. 2 | 64 | £118.42 | 5 days | |
| JBO-512434 | No. 3 | 56 | £110.75 | 5 days | |
| JBO-512436 | No. 4 | 48 | £97.06 | 5 days | |
| JBO-512438 | No. 5 | 44 | £86.41 | 5 days | |
| JBO-512440 | No. 6 | 40 | £72.59 | 5 days | |
| JBO-512442 | No. 8 | 36 | £68.75 | 5 days | |
| JBO-512426 | No. 10 | 32 | £63.28 | 5 days | |
| JBO-512431 | No. 12 | 28 | £69.30 | 5 days | |
| JBO-512456 | 1/4 | 28 | £62.41 | 5 days | |
| JBO-512466 | 5/16 | 24 | £62.41 | 5 days | |
| JBO-512462 | 3/8 | 24 | £64.47 | 5 days | |
| JBO-512472 | 7/16 | 20 | £66.89 | 5 days | |
| JBO-512454 | 1/2 | 20 | £71.61 | 5 days | |
| JBO-512478 | 9/16 | 18 | £75.56 | 5 days | |
| JBO-512469 | 5/8 | 18 | £79.83 | 5 days | |
| JBO-512460 | 3/4 | 16 | £89.59 | 5 days | |
| JBO-512476 | 7/8 | 14 | £100.88 | 5 days | |
| JBO-512444 | 1 | 12 | £110.75 | 5 days | |
| JBO-512451 | 1 1/8 | 12 | £126.10 | 5 days | |
| JBO-512449 | 1 1/4 | 12 | £132.68 | 5 days | |
| JBO-512453 | 1 3/8 | 12 | £151.32 | 5 days | |
| JBO-512446 | 1 1/2 | 12 | £166.67 | 5 days | |
| JBO-512422 | No. 0 | 80 | £157.90 | 5 days | |
| JBO-512425 | No. 1 | 72 | £137.06 | 5 days | |
| JBO-512433 | No. 2 | 64 | £154.62 | 5 days | |
| JBO-512435 | No. 3 | 56 | £144.74 | 5 days | |
| JBO-512437 | No. 4 | 48 | £126.10 | 5 days | |
| JBO-512439 | No. 5 | 44 | £111.84 | 5 days | |
| JBO-512441 | No. 6 | 40 | £94.30 | 5 days | |
| JBO-512443 | No. 8 | 36 | £89.05 | 5 days | |
| JBO-512428 | No. 10 | 32 | £82.24 | 5 days | |
| JBO-516811 | No. 12 | 28 | £89.69 | 5 days | |
| JBO-512458 | 1/4 | 28 | £82.02 | 5 days | |
| JBO-512467 | 5/16 | 24 | £82.02 | 5 days | |
| JBO-512463 | 3/8 | 24 | £84.33 | 5 days | |
| JBO-512473 | 7/16 | 20 | £87.73 | 5 days | |
| JBO-512455 | 1/2 | 20 | £93.97 | 5 days | |
| JBO-512479 | 9/16 | 18 | £97.81 | In Stock | |
| JBO-512470 | 5/8 | 18 | £104.82 | 5 days | |
| JBO-512461 | 3/4 | 16 | £117.33 | 5 days | |
| JBO-512477 | 7/8 | 14 | £129.40 | 5 days | |
| JBO-512445 | 1 | 12 | £143.64 | 5 days | |
| JBO-512452 | 1 1/8 | 12 | £163.39 | 5 days | |
| JBO-512450 | 1 1/4 | 12 | £174.35 | 5 days | |
| JBO-513533 | 1 3/8 | 12 | £197.38 | 5 days | |
| JBO-512448 | 1 1/2 | 12 | £214.91 | 5 days | |
| JBO-517341 | No. 0 | 80 | £169.96 | 5 days | |
| JBO-517342 | No. 1 | 72 | £149.13 | 5 days | |
| JBO-517343 | No. 2 | 64 | £166.67 | 5 days | |
| JBO-517344 | No. 3 | 56 | £155.70 | 5 days | |
| JBO-517345 | No. 4 | 48 | £133.78 | 5 days | |
| JBO-517346 | No. 5 | 44 | £120.61 | 5 days | |
| JBO-517347 | No. 6 | 40 | £104.82 | 5 days | |
| JBO-517348 | No. 8 | 36 | £98.80 | 5 days | |
| JBO-512430 | No. 10 | 32 | £91.35 | 5 days | |
| JBO-517349 | No. 12 | 28 | £99.68 | 5 days | |
| JBO-512459 | 1/4 | 28 | £91.01 | 5 days | |
| JBO-512468 | 5/16 | 24 | £91.01 | 5 days | |
| JBO-512464 | 3/8 | 24 | £93.97 | 5 days | |
| JBO-514344 | 7/16 | 20 | £97.72 | 5 days | |
| JBO-516996 | 1/2 | 20 | £104.29 | 5 days | |
| JBO-512480 | 9/16 | 18 | £108.89 | 5 days | |
| JBO-512471 | 5/8 | 18 | £116.23 | 5 days | |
| JBO-516813 | 3/4 | 16 | £129.40 | 5 days | |
| JBO-513423 | 7/8 | 14 | £145.83 | 5 days | |
| JBO-513491 | 1 | 12 | £160.09 | 5 days | |
| JBO-514147 | 1 1/8 | 12 | £182.03 | 5 days | |
| JBO-517350 | 1 1/4 | 12 | £195.18 | 5 days | |
| JBO-514709 | 1 3/8 | 12 | £219.30 | 5 days | |
| JBO-517351 | 1 1/2 | 12 | £239.05 | 5 days | |
| JBO-511537 | No. 12 | 32 | £81.03 | 5 days | |
| JBO-511550 | 1/4 | 32 | £81.03 | 5 days | |
| JBO-511560 | 5/16 | 32 | £84.22 | 5 days | |
| JBO-511558 | 3/8 | 32 | £86.19 | 5 days | |
| JBO-511565 | 7/16 | 2 | £89.16 | 5 days | |
| JBO-511548 | 1/2 | 28 | £90.79 | 5 days | |
| JBO-511569 | 9/16 | 24 | £94.63 | 5 days | |
| JBO-511562 | 5/8 | 24 | £97.93 | 5 days | |
| JBO-511552 | 11/16 | 24 | £101.87 | 5 days | |
| JBO-511556 | 3/4 | 20 | £105.05 | 5 days | |
| JBO-511554 | 13/16 | 20 | £109.65 | 5 days | |
| JBO-511568 | 7/8 | 20 | £115.14 | 5 days | |
| JBO-511555 | 15/16 | 20 | £119.52 | 5 days | |
| JBO-511539 | 1 | 20 | £123.91 | 5 days | |
| JBO-511543 | 1 1/16 | 18 | £130.48 | 5 days | |
| JBO-511542 | 1 1/8 | 18 | £137.06 | 5 days | |
| JBO-511545 | 1 3/16 | 18 | £145.83 | 5 days | |
| JBO-511541 | 1 1/4 | 18 | £152.43 | 5 days | |
| JBO-511544 | 1 3/8 | 18 | £168.86 | 5 days | |
| JBO-511547 | 1 7/16 | 18 | £177.65 | 5 days | |
| JBO-511540 | 1 1/2 | 18 | £186.41 | 5 days | |
| JBO-514880 | 1 9/16 | 18 | £202.87 | 5 days | |
| JBO-517352 | No. 12 | 32 | £107.36 | 5 days | |
| JBO-516900 | 1/4 | 32 | £107.36 | 5 days | |
| JBO-517353 | 5/16 | 32 | £111.84 | 5 days | |
| JBO-517354 | 3/8 | 32 | £114.03 | 5 days | |
| JBO-514710 | 7/16 | 2 | £117.33 | 5 days | |
| JBO-517355 | 1/2 | 28 | £119.52 | 5 days | |
| JBO-517356 | 9/16 | 24 | £124.99 | 5 days | |
| JBO-517357 | 5/8 | 24 | £129.40 | 5 days | |
| JBO-517358 | 11/16 | 24 | £133.78 | 5 days | |
| JBO-514711 | 3/4 | 20 | £139.25 | 5 days | |
| JBO-517359 | 13/16 | 20 | £145.83 | 5 days | |
| JBO-517360 | 7/8 | 20 | £153.51 | 5 days | |
| JBO-517361 | 15/16 | 20 | £160.09 | 5 days | |
| JBO-517362 | 1 | 20 | £163.39 | 5 days | |
| JBO-512599 | 1/4 | 36 | £206.14 | 5 days | |
| JBO-512583 | 1 | 32 | £357.46 | 5 days | |
| JBO-512603 | 11/16 | 16 | £296.06 | 5 days | |
| JBO-512604 | 13/16 | 16 | £304.83 | 5 days | |
| JBO-512618 | 7/8 | 16 | £328.97 | 5 days | |
| JBO-513082 | 1 | 16 | £336.63 | 5 days | |
| JBO-514092 | 1 1/16 | 16 | £339.93 | 5 days | |
| JBO-512593 | 1 3/16 | 16 | £347.59 | 5 days | |
| JBO-512580 | 1 | 14 | £315.79 | 5 days | |
| JBO-512588 | 1 1/16 | 12 | £290.57 | 5 days | |
| JBO-512592 | 1 3/16 | 12 | £309.22 | 5 days | |
| JBO-512594 | 1 5/16 | 12 | £350.89 | 5 days | |
| JBO-512586 | 1 1/8 | 8 | £373.92 | 5 days | |
| JBO-512585 | 1 1/4 | 8 | £425.44 | 5 days | |
| JBO-512591 | 1 3/8 | 8 | £458.34 | 5 days | |
| JBO-512584 | 1 1/2 | 8 | £460.54 | 5 days | |
| JBO-514228 | No. 2 | 56 | £145.83 | 5 days | |
| JBO-511603 | No. 4 | 40 | £124.99 | 5 days | |
| JBO-511604 | No. 6 | 32 | £114.03 | 5 days | |
| JBO-511605 | No. 8 | 32 | £107.57 | 5 days | |
| JBO-514625 | No. 10 | 24 | £110.75 | 5 days | |
| JBO-518292 | 1/4 | 20 | £110.75 | 5 days | |
| JBO-516556 | 5/16 | 18 | £107.57 | 5 days | |
| JBO-515276 | 3/8 | 16 | £109.22 | 5 days | |
| JBO-515969 | 7/16 | 14 | £133.78 | 5 days | |
| JBO-514760 | No. 4 | 48 | £131.59 | 5 days | |
| JBO-518725 | No. 6 | 40 | £118.42 | 5 days | |
| JBO-514327 | No. 8 | 36 | £111.84 | 5 days | |
| JBO-511606 | No. 10 | 32 | £104.51 | 5 days | |
| JBO-517771 | No. 12 | 28 | £110.75 | 5 days | |
| JBO-511609 | 1/4 | 28 | £104.51 | 5 days | |
| JBO-511612 | 5/16 | 24 | £104.51 | 5 days | |
| JBO-511611 | 3/8 | 24 | £107.57 | 5 days | |
| JBO-511615 | 7/16 | 20 | £111.84 | 5 days | |
| JBO-511608 | 1/2 | 20 | £118.42 | 5 days | |
| JBO-511617 | 9/16 | 18 | £124.99 | 5 days | |
| JBO-511614 | 5/8 | 18 | £132.68 | 5 days | |
| JBO-511610 | 3/4 | 16 | £149.13 | 5 days | |
| JBO-511616 | 7/8 | 14 | £164.47 | 5 days | |
| JBO-511607 | 1 | 12 | £179.84 | 5 days | |
| JBO-516765 | 1/4 | 28 | £162.28 | 5 days | |
| JBO-511613 | 5/16 | 24 | £162.28 | 5 days | |
| JBO-520938 | 3/8 | 24 | £167.77 | 5 days | |
| JBO-513270 | 1/2 | 20 | £183.12 | 5 days | |
| JBO-514326 | 3/4 | 16 | £231.36 | 5 days |
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