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JBO Plug Gauge - UNF (STI) Heli Coil Gauge - Right Hand - 2B - 1/4 x 28 - Calibrated (DAkkS Calibration)

SKU:JBO-512712

The JBO Plug Gauge for UNF (STI) is a precision measurement tool designed to verify UNF screw-thread inserts (STIs) with a right-hand orientation. Sized at 1/4 x 28 with a 2B tolerance, it’s an e... Read more ↓
Thread FormUNF (STI)
Size1/4
Pitch28
Gauge TypePlug Gauge (D/E)
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£187.75
Prices shown ex. VAT
5 days estimated lead time — subject to availability
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Free delivery over £50 ex VAT
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14-day returns
30+ years expertise
Klarna
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01732 887334
Mon – Thurs 8:30 – 17:30 · Fri 8:30 – 16:30

Description

The JBO Plug Gauge for UNF (STI) is a precision measurement tool designed to verify UNF screw-thread inserts (STIs) with a right-hand orientation. Sized at 1/4 x 28 with a 2B tolerance, it’s an essential aid for QA labs, machine shops, automotive, and aerospace environments where accurate insert fit matters. Manufactured and assessed to ANSI/ASME thread standards, this gauge delivers reliable checks on threaded inserts and is calibrated to DAkkS standards for traceable accuracy, ensuring measurement data stands up to audits and quality control requirements.

  • DAkkS-calibrated, traceable accuracy: Ensures measurements are backed by formal calibration data, reducing uncertainty and supporting robust quality documentation.
  • UNF (STI) right-hand design with pitch-diameter checks: Specifically tailored for UNF STI inserts, enabling quick, reliable pitch-diameter verification to confirm proper fit.
  • Rugged, knurled construction: Durable, easy-to-handle design that resists slipping in busy workshops and provides repeatable results over many uses.

This plug gauge streamlines inspection workflows by providing fast, repeatable checks that confirm inserts meet specification before assembly. With traceable calibration, you’ll save time during audits and avoid costly rework from misfit inserts, while the sturdy, handheld design keeps it reliable in demanding production environments.

Part Numbers

Protool Part Number
JBO-512712
Brand
JBO
Category
Gauge
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Need cutting data? Call 01732 887334 or email sales@protool-ltd.co.uk.
Delivery

Free UK mainland delivery on orders over £50 ex VAT. In-stock items ordered before 4:30pm are dispatched the same working day. Full delivery information.

Returns

14-day returns on unused stock items in original packaging. Special-order and bespoke tooling is non-returnable. Read our returns policy.

Technical Support

Over 30 years of machining experience behind the counter. Call 01732 887334, Mon–Thurs 8:30–17:30, Fri 8:30–16:30.

Trade Accounts

Credit accounts, contract pricing and scheduled call-off orders available for trade customers. Apply for an account.

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.

Ask our technical team about this tool

Not sure if this is the right tool for your job? Ask us about speeds and feeds, material suitability, holders or alternatives — 30+ years of machining experience on the other end.

Prefer to talk? Call 01732 887334 — Mon–Thurs 8:30–17:30, Fri 8:30–16:30.

Full Range: JBO Plug Gauge UNC Heli Coil - Right Hand - 3B - Calibrated (DAkkS Calibration)

View full collection →

You are viewing JBO-512712. Click any other SKU to view its full details.

Product SKUSizePitchPriceStock Order
JBO-512689 No. 256£167.77 5 days
JBO-512692 No. 440£214.08 5 days
JBO-512694 No. 540£212.97 5 days
JBO-512695 No. 632£197.63 5 days
JBO-512697 No. 832£189.95 5 days
JBO-512687 No. 1024£187.75 5 days
JBO-512688 No. 1224£204.20 5 days
JBO-512700 1/420£187.75 5 days
JBO-512703 5/1618£197.63 5 days
JBO-512702 3/816£211.89 5 days
JBO-512699 1/213£306.19 5 days
JBO-512704 5/811£319.34 5 days
JBO-513095 No. 448£227.23 5 days
JBO-512707 No. 640£206.40 5 days
JBO-512709 No. 836£195.44 5 days
JBO-512705 No. 1032£187.75 5 days
JBO-512712 Viewing1/428£187.75 5 days
JBO-512716 5/1624£197.63 5 days
JBO-512715 3/824£211.89 5 days
JBO-513343 7/1620£246.96 5 days
JBO-512711 1/220£306.19 5 days
JBO-512718 5/818£316.05 5 days
JBO-512693 No. 440£298.51 5 days
JBO-512696 No. 632£274.37 5 days
JBO-512698 No. 832£263.41 5 days
JBO-512706 No. 1032£259.03 5 days
JBO-512713 1/428£259.03 5 days
JBO-512717 UNF (STI)5/16£275.48 5 days

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