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JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - No. 4 x 40
SKU:JBO-504041
JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - No. 4 x 40 is a precision inspection tool designed to verify external thread diameters to UNC specifications. Built for engineers, machinists, ...
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Specification
| Thread Form | UNC |
| Size | No. 4 |
| Pitch | 40 |
| Gauge Type | Ring Gauge (GO) |
| Thread Direction | Left Hand |
| Tolerance | 2A |
£112.95
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
JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - No. 4 x 40 is a precision inspection tool designed to verify external thread diameters to UNC specifications. Built for engineers, machinists, quality teams, and workshop technicians, it provides a fast, reliable go gauge for confirming thread conformity on left‑hand UNC components. Its rugged design and exact dimensions help streamline acceptance testing and reduce rework, even in demanding production environments.
- Precise GO verification for UNC external threads: Quickly confirms that a component’s external thread diameter conforms to the UNC left‑hand 2A specification, speeding up inspection and minimizing guesswork.
- Hardened steel for durability: Built to withstand daily shop use, resisting wear and maintaining accurate measurements over many cycles.
- Simple, fast identification of compliant parts: User‑friendly design supports clear pass/fail decisions at a glance, improving workflow and traceability in quality control.
Using this GO gauge helps you tighten quality control, shorten inspection times, and ensure consistent results across parts and batches. The durable construction reduces downtime from tool wear, while the precise dimensions deliver repeatable measurements you can trust for reliable assemblies and compliant production output.
| Thread Form | UNC |
| Size | No. 4 |
| Pitch | 40 |
| 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-504041. 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 Viewing | 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 | 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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