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JBO Thread Ring Gauge (GO) - UNF - Left Hand - 2A - No. 4 x 48
SKU:JBO-506449
The JBO Thread Ring Gauge (GO) - UNF - Left Hand - 2A - No. 4 x 48 is a purpose-built go gauge designed to verify external UNF left‑hand threads. It helps machinists, inspectors, and quality team...
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Specification
| Thread Form | UNF |
| Size | No. 4 |
| Pitch | 48 |
| Gauge Type | Ring Gauge (GO) |
| Thread Direction | Left Hand |
| Tolerance | 2A |
£121.72
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) - UNF - Left Hand - 2A - No. 4 x 48 is a purpose-built go gauge designed to verify external UNF left‑hand threads. It helps machinists, inspectors, and quality teams quickly determine whether a threaded component meets the required minimum diameter, making QC checks straightforward and reliable.
Crafted from hardened steel, this gauge offers exceptional wear resistance and long-term durability in busy workshop environments. The knurled outer edge provides a secure, comfortable grip for repeated use, while the precisely machined bore and ring geometry deliver dependable GO checks that clearly indicate proper conformity.
- UNF Left-Hand GO Gauge, No.4 x 48: specifically matched to UNF left-hand threads in size No.4, enabling fast, accurate diameter verification and consistent inspections.
- Hardened steel construction: delivers outstanding wear resistance and longevity, maintaining accuracy through many cycles of use in demanding settings.
- Ergonomic, easy‑grip design with clear GO indication: knurled edge and straightforward pass/fail feedback help inspectors identify compliant parts quickly and confidently.
Using this gauge streamlines your threading inspections, reduces rework, and supports reliable, repeatable results across production runs. It integrates seamlessly into standard quality control workflows, ensuring parts meet specification with minimal downtime and maximum confidence.
| Thread Form | UNF |
| Size | No. 4 |
| Pitch | 48 |
| 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-506449. 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 | 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 Viewing | 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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