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JBO Thread Ring Gauge (NoGo) - UNJF - Right Hand - 3A - 1/2 x 20
SKU:JBO-502985
The JBO Thread Ring Gauge (NoGo) is a precision tool designed to verify external threads against Unified thread standards. Built for UNJF right‑hand threads in the 1/2 x 20 size and 3A class, it ...
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Specification
| Thread Form | UNJF |
| Size | 1/2 |
| Pitch | 20 |
| Gauge Type | Ring Gauge (NoGo) |
| Thread Direction | Right Hand |
| Tolerance | 3A |
£128.29
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 (NoGo) is a precision tool designed to verify external threads against Unified thread standards. Built for UNJF right‑hand threads in the 1/2 x 20 size and 3A class, it provides a reliable, quick way to confirm correct thread engagement and fit on fasteners, collars, and threaded components.
This gauge is an essential companion for engineering and quality teams across manufacturing, automotive, and aerospace environments. Its straightforward NoGo design helps inspectors identify non-conforming threads at a glance, supporting consistent assembly and reducing the risk of misfits in critical applications.
- UNJF 1/2 x 20 Right‑Hand (3A) specification: Precisely machined to standard external thread dimensions, enabling accurate, repeatable Go/NoGo checks that align with your production specs.
- NoGo quick pass/fail verification: The NoGo feature provides an immediate, visual indication of non‑conforming threads, speeding up inspection and ensuring only compliant parts proceed.
- Hardened steel for durability: Crafted from hardened steel to resist wear, maintain accuracy over many cycles, and withstand demanding shop environments.
By integrating this gauge into your workflow, you gain faster quality control, reduced rework, and improved confidence that threaded parts will meet exacting standards in assembly and service. It’s a reliable, long‑lasting tool that supports accurate inspections from incoming parts through final assembly.
| Thread Form | UNJF |
| Size | 1/2 |
| Pitch | 20 |
| Gauge Type | Ring Gauge (NoGo) |
| Thread Direction | Right Hand |
| Tolerance | 3A |
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 (NoGo) - Unified
View full collection →You are viewing JBO-502985. Click any other SKU to view its full details.
| Product SKU | Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|
| JBO-501051 | No. 1 | 64 | £114.03 | 5 days | |
| JBO-501057 | No. 2 | 56 | £86.19 | 5 days | |
| JBO-501061 | No. 3 | 48 | £103.52 | 5 days | |
| JBO-501063 | No. 4 | 40 | £75.45 | 5 days | |
| JBO-501066 | No. 5 | 40 | £69.08 | 5 days | |
| JBO-501067 | No. 6 | 32 | £58.90 | 5 days | |
| JBO-501070 | No. 8 | 32 | £55.39 | 5 days | |
| JBO-501053 | No. 10 | 24 | £54.28 | 5 days | |
| JBO-501055 | No. 12 | 24 | £63.28 | 5 days | |
| JBO-501080 | 1/4 | 20 | £51.88 | 5 days | |
| JBO-501088 | 5/16 | 18 | £55.15 | 5 days | |
| JBO-501085 | 3/8 | 16 | £60.08 | 5 days | |
| JBO-501093 | 7/16 | 14 | £65.48 | 5 days | |
| JBO-501078 | 1/2 | 13 | £71.94 | 5 days | |
| JBO-501097 | 9/16 | 12 | £99.25 | 5 days | |
| JBO-501091 | 5/8 | 11 | £84.43 | 5 days | |
| JBO-501083 | 3/4 | 10 | £104.51 | 5 days | |
| JBO-501095 | 7/8 | 9 | £127.21 | 5 days | |
| JBO-501072 | 1 | 8 | £137.06 | 5 days | |
| JBO-501075 | 1 1/8 | 7 | £183.12 | 5 days | |
| JBO-501074 | 1 1/4 | 7 | £198.46 | 5 days | |
| JBO-501077 | 1 3/8 | 6 | £213.83 | 5 days | |
| JBO-501073 | 1 1/2 | 6 | £233.56 | 5 days | |
| JBO-501076 | 1 3/4 | 5 | £292.77 | 5 days | |
| JBO-503352 | 2 | 4.5 | £335.54 | 5 days | |
| JBO-502964 | 2 1/4 | 4.5 | £382.68 | 5 days | |
| JBO-541018 | 2 1/2 | 4 | £427.63 | 5 days | |
| JBO-507589 | 2 3/4 | 4 | £476.99 | 5 days | |
| JBO-501052 | No. 1 | 64 | £167.77 | 5 days | |
| JBO-501060 | No. 2 | 56 | £128.29 | 5 days | |
| JBO-501062 | No. 3 | 48 | £135.97 | 5 days | |
| JBO-501065 | No. 4 | 40 | £105.48 | 5 days | |
| JBO-502874 | No. 5 | 40 | £96.83 | 5 days | |
| JBO-501068 | No. 6 | 32 | £82.35 | 5 days | |
| JBO-501071 | No. 8 | 32 | £77.41 | 5 days | |
| JBO-501054 | No. 10 | 24 | £77.64 | 5 days | |
| JBO-501056 | No. 12 | 24 | £82.14 | 5 days | |
| JBO-501081 | 1/4 | 20 | £76.22 | 5 days | |
| JBO-501089 | 5/16 | 18 | £81.03 | 5 days | |
| JBO-501086 | 3/8 | 16 | £88.06 | 5 days | |
| JBO-501094 | 7/16 | 14 | £98.14 | 5 days | |
| JBO-501079 | 1/2 | 13 | £107.90 | 5 days | |
| JBO-503178 | 9/16 | 12 | £120.61 | 5 days | |
| JBO-501092 | 5/8 | 11 | £128.29 | 5 days | |
| JBO-502798 | 3/4 | 10 | £156.81 | 5 days | |
| JBO-501096 | 7/8 | 9 | £189.69 | 5 days | |
| JBO-503179 | 1 | 8 | £209.44 | 5 days | |
| JBO-506412 | No. 1 | 64 | £163.39 | 5 days | |
| JBO-506413 | No. 2 | 56 | £129.40 | 5 days | |
| JBO-506414 | No. 3 | 48 | £148.02 | 5 days | |
| JBO-504045 | No. 4 | 40 | £112.95 | 5 days | |
| JBO-506415 | No. 5 | 40 | £103.52 | 5 days | |
| JBO-501069 | No. 6 | 32 | £88.15 | 5 days | |
| JBO-506416 | No. 8 | 32 | £83.11 | 5 days | |
| JBO-503428 | No. 10 | 24 | £81.36 | 5 days | |
| JBO-505540 | No. 12 | 24 | £87.84 | 5 days | |
| JBO-501082 | 1/4 | 20 | £77.76 | 5 days | |
| JBO-501090 | 5/16 | 18 | £82.80 | 5 days | |
| JBO-501087 | 3/8 | 16 | £90.25 | 5 days | |
| JBO-506417 | 7/16 | 14 | £98.14 | 5 days | |
| JBO-506418 | 1/2 | 13 | £107.90 | 5 days | |
| JBO-506420 | 9/16 | 12 | £118.42 | 5 days | |
| JBO-504046 | 5/8 | 11 | £130.48 | 5 days | |
| JBO-501084 | 3/4 | 10 | £156.81 | 5 days | |
| JBO-506422 | 7/8 | 9 | £189.69 | 5 days | |
| JBO-506423 | 1 | 8 | £209.44 | 5 days | |
| JBO-506424 | 1 1/8 | 7 | £245.62 | 5 days | |
| JBO-506426 | 1 1/4 | 7 | £268.65 | 5 days | |
| JBO-506428 | 1 3/8 | 6 | £299.34 | 5 days | |
| JBO-506430 | 1 1/2 | 6 | £317.99 | 5 days | |
| JBO-501099 | No. 0 | 80 | £126.10 | 5 days | |
| JBO-501101 | No. 1 | 72 | £105.38 | 5 days | |
| JBO-501108 | No. 2 | 64 | £105.26 | 5 days | |
| JBO-501110 | No. 3 | 56 | £104.95 | 5 days | |
| JBO-501112 | No. 4 | 48 | £92.98 | 5 days | |
| JBO-501114 | No. 5 | 44 | £74.55 | 5 days | |
| JBO-501116 | No. 6 | 40 | £71.72 | 5 days | |
| JBO-501118 | No. 8 | 36 | £66.35 | 5 days | |
| JBO-501103 | No. 10 | 32 | £52.75 | 5 days | |
| JBO-501106 | No. 12 | 28 | £63.28 | 5 days | |
| JBO-501130 | 1/4 | 28 | £51.97 | 5 days | |
| JBO-501140 | 5/16 | 24 | £55.15 | 5 days | |
| JBO-501137 | 3/8 | 24 | £60.08 | 5 days | |
| JBO-501146 | 7/16 | 20 | £64.82 | 5 days | |
| JBO-501127 | 1/2 | 20 | £71.94 | 5 days | |
| JBO-501152 | 9/16 | 18 | £77.41 | 5 days | |
| JBO-501143 | 5/8 | 18 | £85.65 | 5 days | |
| JBO-501133 | 3/4 | 16 | £99.68 | 5 days | |
| JBO-501149 | 7/8 | 14 | £117.33 | 5 days | |
| JBO-501120 | 1 | 12 | £131.59 | 5 days | |
| JBO-501125 | 1 1/8 | 12 | £148.02 | 5 days | |
| JBO-501124 | 1 1/4 | 12 | £161.19 | 5 days | |
| JBO-501126 | 1 3/8 | 12 | £175.43 | 5 days | |
| JBO-501123 | 1 1/2 | 12 | £186.41 | 5 days | |
| JBO-501100 | No. 0 | 80 | £176.54 | 5 days | |
| JBO-501102 | No. 1 | 72 | £148.02 | 5 days | |
| JBO-501109 | No. 2 | 64 | £137.06 | 5 days | |
| JBO-501111 | No. 3 | 56 | £135.97 | 5 days | |
| JBO-501113 | No. 4 | 48 | £121.72 | 5 days | |
| JBO-501115 | No. 5 | 44 | £96.83 | 5 days | |
| JBO-501117 | No. 6 | 40 | £93.10 | 5 days | |
| JBO-501119 | No. 8 | 36 | £85.65 | 5 days | |
| JBO-501104 | No. 10 | 32 | £73.58 | 5 days | |
| JBO-501107 | No. 12 | 28 | £82.14 | 5 days | |
| JBO-501131 | 1/4 | 28 | £72.81 | 5 days | |
| JBO-501141 | 5/16 | 24 | £77.10 | 5 days | |
| JBO-501138 | 3/8 | 24 | £84.22 | 5 days | |
| JBO-501147 | 7/16 | 20 | £90.46 | 5 days | |
| JBO-501128 | 1/2 | 20 | £100.55 | 5 days | |
| JBO-501153 | 9/16 | 18 | £108.45 | 5 days | |
| JBO-501144 | 5/8 | 18 | £119.52 | 5 days | |
| JBO-501134 | 3/4 | 16 | £139.25 | 5 days | |
| JBO-501150 | 7/8 | 14 | £164.47 | 5 days | |
| JBO-501121 | 1 | 12 | £183.12 | 5 days | |
| JBO-502758 | 1 1/8 | 12 | £207.25 | 5 days | |
| JBO-503208 | 1 1/4 | 12 | £225.87 | 5 days | |
| JBO-503210 | 1 3/8 | 12 | £245.62 | 5 days | |
| JBO-502767 | 1 1/2 | 12 | £264.27 | 5 days | |
| JBO-506458 | No. 0 | 80 | £176.54 | 5 days | |
| JBO-506460 | No. 1 | 72 | £148.02 | 5 days | |
| JBO-506461 | No. 2 | 64 | £137.06 | 5 days | |
| JBO-506462 | No. 3 | 56 | £135.97 | 5 days | |
| JBO-506463 | No. 4 | 48 | £121.72 | 5 days | |
| JBO-506465 | No. 5 | 44 | £96.83 | 5 days | |
| JBO-506466 | No. 6 | 40 | £93.10 | 5 days | |
| JBO-506468 | No. 8 | 36 | £85.65 | 5 days | |
| JBO-501105 | No. 10 | 32 | £76.44 | 5 days | |
| JBO-506470 | No. 12 | 28 | £83.67 | 5 days | |
| JBO-501132 | 1/4 | 28 | £72.81 | 5 days | |
| JBO-501142 | 5/16 | 24 | £81.03 | 5 days | |
| JBO-501139 | 3/8 | 24 | £84.22 | 5 days | |
| JBO-501148 | 7/16 | 20 | £92.98 | 5 days | |
| JBO-501129 | 1/2 | 20 | £104.72 | 5 days | |
| JBO-501154 | 9/16 | 18 | £116.23 | 5 days | |
| JBO-501145 | 5/8 | 18 | £119.52 | 5 days | |
| JBO-501135 | 3/4 | 16 | £139.25 | 5 days | |
| JBO-501151 | 7/8 | 14 | £164.47 | 5 days | |
| JBO-501122 | 1 | 12 | £183.12 | 5 days | |
| JBO-503126 | 1 1/8 | 12 | £207.25 | 5 days | |
| JBO-506473 | 1 1/4 | 12 | £225.87 | 5 days | |
| JBO-506476 | 1 3/8 | 12 | £245.62 | 5 days | |
| JBO-502851 | 1 1/2 | 12 | £264.27 | 5 days | |
| JBO-500006 | No. 12 | 32 | £74.79 | 5 days | |
| JBO-500019 | 1/4 | 32 | £74.79 | 5 days | |
| JBO-500033 | 5/16 | 32 | £80.16 | 5 days | |
| JBO-500029 | 3/8 | 32 | £85.20 | 5 days | |
| JBO-500036 | 7/16 | 2 | £90.46 | 5 days | |
| JBO-500016 | 1/2 | 28 | £94.52 | 5 days | |
| JBO-500040 | 9/16 | 24 | £104.60 | 5 days | |
| JBO-500034 | 5/8 | 24 | £111.84 | 5 days | |
| JBO-500022 | 11/16 | 24 | £120.61 | 5 days | |
| JBO-500025 | 3/4 | 20 | £127.21 | 5 days | |
| JBO-500023 | 13/16 | 20 | £133.78 | 5 days | |
| JBO-500039 | 7/8 | 20 | £144.74 | 5 days | |
| JBO-500024 | 15/16 | 20 | £155.70 | 5 days | |
| JBO-500007 | 1 | 20 | £163.39 | 5 days | |
| JBO-500011 | 1 1/16 | 18 | £173.24 | 5 days | |
| JBO-505428 | 1 1/8 | 18 | £179.84 | 5 days | |
| JBO-500013 | 1 3/16 | 18 | £189.69 | 5 days | |
| JBO-500009 | 1 1/4 | 18 | £202.87 | 5 days | |
| JBO-500014 | 1 5/16 | 18 | £213.83 | 5 days | |
| JBO-500012 | 1 3/8 | 18 | £225.87 | 5 days | |
| JBO-500015 | 1 7/16 | 18 | £236.85 | 5 days | |
| JBO-500008 | 1 1/2 | 18 | £248.90 | 5 days | |
| JBO-503813 | 1 9/16 | 18 | £266.46 | 5 days | |
| JBO-506504 | No. 12 | 32 | £105.71 | 5 days | |
| JBO-500021 | 1/4 | 32 | £105.71 | 5 days | |
| JBO-506505 | 5/16 | 32 | £116.23 | 5 days | |
| JBO-506506 | 3/8 | 32 | £121.72 | 5 days | |
| JBO-500038 | 7/16 | 2 | £127.21 | 5 days | |
| JBO-503779 | 1/2 | 28 | £133.78 | 5 days | |
| JBO-505872 | 9/16 | 24 | £145.83 | 5 days | |
| JBO-503137 | 5/8 | 24 | £167.77 | 5 days | |
| JBO-506507 | 11/16 | 24 | £178.73 | 5 days | |
| JBO-500028 | 3/4 | 20 | £188.61 | 5 days | |
| JBO-506508 | 13/16 | 20 | £202.87 | 5 days | |
| JBO-506509 | 7/8 | 20 | £218.21 | 5 days | |
| JBO-506510 | 15/16 | 20 | £233.56 | 5 days | |
| JBO-504057 | 1 | 20 | £244.52 | 5 days | |
| JBO-501232 | 1/4 | 36 | £207.25 | 5 days | |
| JBO-501205 | 1 | 32 | £421.06 | 5 days | |
| JBO-501237 | 11/16 | 16 | £350.89 | 5 days | |
| JBO-501240 | 13/16 | 16 | £307.02 | 5 days | |
| JBO-501259 | 7/8 | 16 | £313.60 | 5 days | |
| JBO-501204 | 1 | 16 | £350.89 | 5 days | |
| JBO-540054 | 1 1/16 | 16 | £370.62 | 5 days | |
| JBO-501223 | 1 3/16 | 16 | £407.90 | 5 days | |
| JBO-501202 | 1 | 14 | £288.38 | 5 days | |
| JBO-501214 | 1 1/16 | 12 | £321.28 | 5 days | |
| JBO-501222 | 1 3/16 | 12 | £364.04 | 5 days | |
| JBO-501225 | 1 5/16 | 12 | £359.66 | 5 days | |
| JBO-502756 | 1 5/8 | 12 | £459.45 | 5 days | |
| JBO-501216 | 1 3/4 | 12 | £441.89 | 5 days | |
| JBO-501227 | 1 7/8 | 12 | £482.48 | 5 days | |
| JBO-502835 | 2 | 12 | £490.14 | 5 days | |
| JBO-501213 | 1 1/8 | 8 | £357.46 | 5 days | |
| JBO-501209 | 1 1/4 | 8 | £359.66 | 5 days | |
| JBO-501221 | 1 3/8 | 8 | £387.07 | 5 days | |
| JBO-501207 | 1 1/2 | 8 | £463.83 | 5 days | |
| JBO-501224 | 1 5/8 | 8 | £486.86 | 5 days | |
| JBO-501218 | 1 3/4 | 8 | £552.65 | 5 days | |
| JBO-503355 | 2 | 8 | £596.51 | 5 days | |
| JBO-504211 | No. 2 | 56 | £167.77 | 5 days | |
| JBO-503594 | No. 4 | 40 | £139.25 | 5 days | |
| JBO-500119 | No. 6 | 32 | £120.61 | 5 days | |
| JBO-500120 | No. 8 | 32 | £111.84 | 5 days | |
| JBO-544018 | No. 10 | 24 | £111.84 | 5 days | |
| JBO-544019 | 1/4 | 20 | £111.84 | 5 days | |
| JBO-544020 | 5/16 | 18 | £111.84 | 5 days | |
| JBO-544021 | 3/8 | 16 | £116.23 | 5 days | |
| JBO-554997 | 7/16 | 14 | £148.02 | 5 days | |
| JBO-544022 | No. 4 | 48 | £143.64 | 5 days | |
| JBO-505348 | No. 6 | 40 | £117.33 | 5 days | |
| JBO-500123 | No. 8 | 36 | £108.02 | 5 days | |
| JBO-500122 | No. 10 | 32 | £94.30 | 5 days | |
| JBO-504245 | No. 12 | 28 | £108.02 | 5 days | |
| JBO-500125 | 1/4 | 28 | £94.30 | 5 days | |
| JBO-500127 | 5/16 | 24 | £98.80 | 5 days | |
| JBO-500126 | 3/8 | 24 | £106.58 | 5 days | |
| JBO-500129 | 7/16 | 20 | £116.23 | 5 days | |
| JBO-502985 Viewing | 1/2 | 20 | £128.29 | 5 days | |
| JBO-500130 | 9/16 | 18 | £135.97 | 5 days | |
| JBO-500128 | 5/8 | 18 | £153.51 | 5 days | |
| JBO-503100 | 3/4 | 16 | £176.54 | 5 days | |
| JBO-503652 | 7/8 | 14 | £207.25 | 5 days | |
| JBO-500124 | 1 | 12 | £233.56 | 5 days | |
| JBO-544318 | 1/4 | 28 | £151.32 | 5 days | |
| JBO-504653 | 5/16 | 24 | £159.00 | 5 days | |
| JBO-503867 | 3/8 | 24 | £171.05 | 5 days | |
| JBO-544329 | 1/2 | 20 | £206.14 | 5 days | |
| JBO-503729 | 3/4 | 16 | £248.90 | 5 days |
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