JBO Thread Ring Gauge (NoGo) - UNF - Left Hand - 2A - 1/2 x 20

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JBO Thread Ring Gauge (NoGo) - UNF - Left Hand - 2A - 1/2 x 20

SKU:JBO-501129

Specification

Thread Form	UNF
Size	1/2
Pitch	20
Gauge Type	Ring Gauge (NoGo)
Thread Direction	Left Hand
Tolerance	2A

£104.72

Prices shown ex. VAT

5 days estimated lead time — subject to availability

Free delivery over £50 ex VAT

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14-day returns

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01732 887334

Mon – Thurs 8:30 – 17:30 · Fri 8:30 – 16:30

The JBO Thread Ring Gauge NoGo for UNF threads is a precision inspection tool designed to verify external thread diameters with confidence. It's ideal for manufacturers, automotive shops, aerospace maintenance, and metalworking teams, helping confirm that threaded components meet Unified thread standards and will perform as intended.

This NoGo gauge provides a clear pass/fail indication for 1/2 x 20 left-hand threads in the 2A class, enabling fast, accurate checks in busy production lines and quality labs.

NoGo design for fast pass/fail checks: Quickly determine whether a thread is within tolerance or out of spec, reducing inspection time and preventing misfits in assembly.
UNF 1/2 x 20 Left-Hand, 2A specification: Precisely built to the exact UNF thread size and hand, ensuring consistent measurements and reliable validation of parts that use this configuration.
Hardened steel construction for durability: Withstand daily workshop use, resist wear, and maintain accuracy over thousands of measurements, even in demanding environments.

Using the JBO NoGo Ring Gauge supports a streamlined quality workflow: it delivers dependable, quick checks that minimize rework, ensure proper thread engagement, and help you meet customer and industry specifications with every lot of parts.

Thread Form	UNF
Size	1/2
Pitch	20
Gauge Type	Ring Gauge (NoGo)
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.

Bill

★★★★★

first place we look

honest about stock and prices are competitive.

Phil

★★★★★

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 .

Graham

★★★★★

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.

Jeremy

Full Range: JBO Thread Ring Gauges (NoGo) - Unified

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You are viewing JBO-501129. Click any other SKU to view its full details.

Product SKU	Size	Pitch	Price	Stock

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 Viewing	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	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