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JBO Thread Plug Gauge - UNC Go-No/Go - Left Hand - 2B - No. 4 x 40
SKU:JBO-514701
The JBO Thread Plug Gauge is a precision tool for verifying No. 4 x 40 (4-40) left-hand UNC threads. Designed for inspectors, machinists, and technicians across manufacturing, automotive, and aero...
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Specifications at a glance
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| Thread Form | UNC |
| Size | No. 4 |
| Pitch | 40 |
| Gauge Type | Plug Gauge (D/E) |
£118.42
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.
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Description
The JBO Thread Plug Gauge is a precision tool for verifying No. 4 x 40 (4-40) left-hand UNC threads. Designed for inspectors, machinists, and technicians across manufacturing, automotive, and aerospace environments, it helps ensure threaded holes and mating parts conform to Unified thread standards with speed and accuracy.
Featuring a 2B tolerance grade and a robust go/no-go design, this gauge delivers fast pass/fail checks, reduces inspection downtime, and supports consistently reliable assemblies in busy workshop settings.
- Go/No-Go quick conformance checks: Quickly determine whether the thread is within specification by testing against the go and no-go limits, enabling faster acceptance/rejection decisions and less rework.
- 2B tolerance for reliable results: The 2B tolerance grade ensures repeatable measurements across parts, reducing variability and helping quality teams meet tight standards.
- Durable, ergonomic construction: Knurled handle and sturdy ends withstand daily shop use, providing a secure grip and consistent readings even in demanding environments.
Using the JBO Thread Plug Gauge streamlines your thread inspection workflow. It minimizes guesswork, speeds up quality checks, and helps prevent mismatches in critical assemblies. With clear go/no-go feedback and durable design, you can rely on accurate evaluations every shift, improving first-pass yields and reducing downtime across production lines.
Part Numbers
- Protool Part Number
- JBO-514701
- Brand
- JBO
- Category
- Gauge
No downloads are attached to this product yet.
Need cutting data? Call 01732 887334 or email sales@protool-ltd.co.uk.
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.
Ask our technical team about this tool
Full Range: JBO Thread Plug Gauges - Unified Go-No/Go
View full collection →You are viewing JBO-514701. 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 | 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 Viewing | 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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