The JBO Thread Plug Gauge is a precision tool for quickly verifying UNF threaded holes and fittings. Designed for right-hand threads and sized No. 4 x 48 with 2B tolerance, it delivers clear go/no-go results you can trust in any workshop.

Used across manufacturing, automotive, and aerospace environments, this gauge helps ensure threads conform to Unified standards, reduces guesswork, and speeds up inspection cycles where tight tolerances matter.

• UNF Go/No-Go design for fast, decisive checks: Quickly determine if a thread is within spec by testing both the go and no-go limits—saving time and preventing misfits in assembly.
• Right-hand, No. 4 x 48 size: Specifically calibrated for right-handed UNF threads, ensuring accurate checks that match your production parts and reducing the risk of incorrect replacements.
• Durable, precision-ground construction with a knurled body: Built to withstand daily use in busy shops, with smooth ends and a textured grip for reliable readings and long service life.

With the JBO Thread Plug Gauge, inspections become quicker, decisions become clearer, and thread quality stays consistently within specification. The go/no-go workflow minimizes downtime, reduces rework, and helps teams train faster while delivering reliable results for every part that uses UNF threads.