Dispatch Hours
Orders dispatched Monday to Friday between 8am and 5pm (4:30pm on Fridays).
- Mon – Thurs8:00 – 17:00
- Friday8:00 – 16:30
- Sat & SunClosed
The Truthread Plug Gauges - UN (UNC/UNF/UNEF) are precision instruments designed for measuring the internal threads of threaded holes. These plug gauges are specifically engineered to conform to the Unified National Coarse (UNC), Unified National Fine (UNF), and Unified National Extra Fine (UNEF) thread standards. Each plug gauge in the series is meticulously crafted with high accuracy and tight tolerances to ensure reliable and consistent measurements. The gauges feature a tapered design with a handle for easy insertion into threaded holes, allowing users to quickly and accurately assess the fit and quality of the threads.

Click any SKU to view full product details, specifications and datasheets.
| Product SKU | Thread Form | Size | Pitch | Price | Stock | Order |
|---|---|---|---|---|---|---|
| PRO2100001 | UNC | No. 4 | 40 | £62.96 | In Stock |
|
| PRO2100002 | UNF | No. 4 | 48 | £62.96 | In Stock |
|
| PRO2100003 | UNC | No. 5 | 40 | £62.96 | In Stock |
|
| PRO2100004 | UNF | No. 5 | 44 | £62.96 | Out of Stock |
|
| PRO2100005 | UNC | No. 6 | 32 | £51.52 | In Stock |
|
| PRO2100006 | UNF | No. 6 | 40 | £51.52 | In Stock |
|
| PRO2100007 | UNC | No. 8 | 32 | £51.52 | Out of Stock |
|
| PRO2100008 | UNF | No. 8 | 36 | £51.52 | In Stock |
|
| PRO2100009 | UNC | No. 10 | 24 | £51.52 | Out of Stock |
|
| PRO2100010 | UNF | No. 10 | 32 | £51.52 | In Stock |
|
| PRO2100011 | UNC | No. 12 | 24 | £51.52 | In Stock |
|
| PRO2100012 | UNF | No. 12 | 28 | £51.52 | In Stock |
|
| PRO2100013 | UNEF | No. 12 | 32 | £62.96 | In Stock |
|
| PRO2100014 | UNC | 1/4 | 20 | £51.52 | Out of Stock |
|
| PRO2100015 | UNF | 1/4 | 28 | £51.52 | In Stock |
|
| PRO2100016 | UNEF | 1/4 | 32 | £62.96 | In Stock |
|
| PRO2100017 | UNC | 5/16 | 18 | £51.52 | In Stock |
|
| PRO2100018 | UNF | 5/16 | 24 | £51.52 | Out of Stock |
|
| PRO2100019 | UNEF | 5/16 | 32 | £62.96 | In Stock |
|
| PRO2100020 | UNC | 3/8 | 16 | £51.52 | In Stock |
|
| PRO2100021 | UNF | 3/8 | 24 | £51.52 | Out of Stock |
|
| PRO2100022 | UNEF | 3/8 | 32 | £62.96 | In Stock |
|
| PRO2100023 | UNC | 7/16 | 14 | £51.52 | Out of Stock |
|
| PRO2100024 | UNF | 7/16 | 20 | £51.52 | Out of Stock |
|
| PRO2100025 | UNEF | 7/16 | 28 | £62.96 | In Stock |
|
| PRO2100026 | UNC | 1/2 | 13 | £51.52 | In Stock |
|
| PRO2100027 | UNF | 1/2 | 20 | £51.52 | Out of Stock |
|
| PRO2100028 | UNEF | 1/2 | 28 | £62.96 | Out of Stock |
|
| PRO2100029 | UNC | 9/16 | 12 | £68.69 | In Stock |
|
| PRO2100030 | UNF | 9/16 | 18 | £57.24 | Out of Stock |
|
| PRO2100031 | UN | 9/16 | 20 | £80.14 | Out of Stock |
|
| PRO2100032 | UNEF | 9/16 | 24 | £91.58 | In Stock |
|
| PRO2100033 | UNC | 5/8 | 11 | £68.69 | Out of Stock |
|
| PRO2100034 | UNF | 5/8 | 18 | £57.24 | Out of Stock |
|
| PRO2100035 | UN | 5/8 | 20 | £80.14 | Out of Stock |
|
| PRO2100036 | UNEF | 5/8 | 24 | £91.58 | In Stock |
|
| PRO2100037 | UN | 11/16 | 12 | £85.86 | Out of Stock |
|
| PRO2100038 | UN | 11/16 | 16 | £85.86 | Out of Stock |
|
| PRO2100039 | UN | 11/16 | 20 | £91.58 | In Stock |
|
| PRO2100040 | UNEF | 11/16 | 24 | £91.58 | Out of Stock |
|
| PRO2100041 | UNC | 3/4 | 10 | £85.86 | Out of Stock |
|
| PRO2100042 | UN | 3/4 | 12 | £85.86 | In Stock |
|
| PRO2100043 | UNF | 3/4 | 16 | £68.69 | Out of Stock |
|
| PRO2100044 | UNEF | 3/4 | 20 | £91.58 | Out of Stock |
|
| PRO2100045 | UN | 13/16 | 12 | £103.03 | Out of Stock |
|
| PRO2100046 | UN | 13/16 | 16 | £103.03 | In Stock |
|
| PRO2100047 | UNEF | 13/16 | 20 | £103.03 | Out of Stock |
|
| PRO2100048 | UNEF | 13/16 | 24 | £114.48 | Out of Stock |
|
| PRO2100049 | UNC | 7/8 | 9 | £103.03 | In Stock |
|
| PRO2100050 | UN | 7/8 | 12 | £91.58 | Out of Stock |
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| PRO2100051 | UNF | 7/8 | 14 | £68.69 | Out of Stock |
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| PRO2100052 | UN | 7/8 | 16 | £97.31 | In Stock |
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| PRO2100053 | UNEF | 7/8 | 20 | £97.31 | Out of Stock |
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| PRO2100054 | UN | 15/16 | 12 | £103.03 | In Stock |
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| PRO2100055 | UN | 15/16 | 16 | £103.03 | Out of Stock |
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| PRO2100056 | UNEF | 15/16 | 20 | £103.03 | In Stock |
|
| PRO2100057 | UNC | 1 | 8 | £120.20 | Out of Stock |
|
| PRO2100058 | UNF | 1 | 12 | £97.31 | In Stock |
|
| PRO2100059 | UN | 1 | 14 | £97.31 | Out of Stock |
|
| PRO2100060 | UN | 1 | 16 | £97.31 | Out of Stock |
|
| PRO2100061 | UNEF | 1 | 20 | £97.31 | Out of Stock |
|
| PRO2100062 | UNC | 1.1/16 | 8 | £143.10 | Out of Stock |
|
| PRO2100063 | UNF | 1.1/16 | 12 | £103.03 | Out of Stock |
|
| PRO2100064 | UN | 1.1/16 | 16 | £103.03 | In Stock |
|
| PRO2100065 | UNEF | 1.1/16 | 18 | £137.38 | In Stock |
|
| PRO2100066 | UNC | 1.1/8 | 7 | £143.10 | In Stock |
|
| PRO2100067 | UNF | 1.1/8 | 12 | £97.31 | Out of Stock |
|
| PRO2100068 | UN | 1.1/8 | 16 | £97.31 | In Stock |
|
| PRO2100069 | UNEF | 1.1/8 | 18 | £137.38 | In Stock |
|
| PRO2100070 | UN | 1.3/16 | 8 | £143.10 | In Stock |
|
| PRO2100071 | UN | 1.3/16 | 12 | £103.03 | Out of Stock |
|
| PRO2100072 | UN | 1.3/16 | 16 | £103.03 | In Stock |
|
| PRO2100073 | UNEF | 1.3/16 | 18 | £137.38 | In Stock |
|
| PRO2100074 | UNC | 1.1/4 | 7 | £143.10 | In Stock |
|
| PRO2100075 | UN | 1.1/4 | 8 | £143.10 | Out of Stock |
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| PRO2100076 | UNF | 1.1/4 | 12 | £97.31 | Out of Stock |
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| PRO2100077 | UN | 1.1/4 | 16 | £97.31 | Out of Stock |
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| PRO2100078 | UNEF | 1.1/4 | 18 | £137.38 | In Stock |
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| PRO2100079 | UN | 1.1/4 | 20 | £137.38 | In Stock |
|
| PRO2100080 | UN | 1.5/16 | 8 | £143.10 | In Stock |
|
| PRO2100081 | UNF | 1.5/16 | 12 | £103.03 | Out of Stock |
|
| PRO2100082 | UN | 1.5/16 | 16 | £103.03 | In Stock |
|
| PRO2100083 | UNEF | 1.5/16 | 18 | £137.38 | Out of Stock |
|
| PRO2100084 | UN | 1.5/16 | 20 | £137.38 | In Stock |
|
| PRO2100085 | UNC | 1.3/8 | 6 | £157.41 | In Stock |
|
| PRO2100086 | UN | 1.3/8 | 8 | £143.10 | Out of Stock |
|
| PRO2100087 | UNF | 1.3/8 | 12 | £103.03 | Out of Stock |
|
| PRO2100088 | UN | 1.3/8 | 16 | £103.03 | In Stock |
|
| PRO2100089 | UNEF | 1.3/8 | 18 | £137.38 | Out of Stock |
|
| PRO2100090 | UN | 1.3/8 | 20 | £137.38 | Out of Stock |
|
| PRO2100091 | UN | 1.3/8 | 6 | £157.41 | Out of Stock |
|
| PRO2100092 | UN | 1.3/8 | 8 | £143.10 | In Stock |
|
| PRO2100093 | UN | 1.7/16 | 12 | £103.03 | Out of Stock |
|
| PRO2100094 | UNEF | 1.7/16 | 18 | £137.38 | In Stock |
|
| PRO2100095 | UN | 1.7/16 | 20 | £137.38 | In Stock |
|
| PRO2100096 | UNC | 1.1/2 | 6 | £157.41 | Out of Stock |
|
| PRO2100097 | UN | 1.1/2 | 8 | £143.10 | In Stock |
|
| PRO2100098 | UNF | 1.1/2 | 12 | £103.03 | Out of Stock |
|
| PRO2100099 | UN | 1.1/2 | 16 | £103.03 | In Stock |
|
| PRO2100100 | UNEF | 1.1/2 | 18 | £137.38 | In Stock |
|
| PRO2100101 | UN | 1.1/2 | 20 | £137.38 | In Stock |
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Fast dispatch, clear delivery options and a friendly technical team on the end of the phone.
Orders dispatched Monday to Friday between 8am and 5pm (4:30pm on Fridays).
| Service | Cost |
|---|---|
| Royal Mail Tracked 24 | £5.90 |
| DPD Standard Next Day | £8.00 |
| Royal Mail Special Delivery by 1pm | £12.50 |
| DPD Saturday Delivery | £25.00 |
Saturday delivery available on orders placed before 4pm Friday. T&Cs and geographical exclusions apply (Republic of Ireland, Northern Ireland, Scottish Highlands, Channel Islands & others) — see our delivery page for full details.
If an item isn't right, sending it back is simple and hassle-free.
Read our returns policy →Our specialist team can advise on tooling choice, specifications and compatibility.
01732 887334 info@protool-ltd.co.uk