The JBO Thread Plug Gauge is a precision tool designed for inspecting metric fine-thread holes. It’s ideal for machinists, quality inspectors, engineers, and workshop technicians who need quick, reliable thread checks to ensure parts fit together smoothly.

Built for M39 x 2 right-hand threads with a 6H tolerance, the Go/No-Go design lets you determine at a glance whether a threaded hole is within specification, helping you avoid assembly surprises.

• Go/No-Go quick checks: Instantly confirm if the hole meets both minimum (Go) and maximum (No-Go) limits, speeding up acceptance and reducing rework.
• Precisely matched to M39 x 2 right-hand threads: Designed for metric fine threads to ensure reliable testing for common hole sizes and minimize guessing.
• Hardened steel construction: Built to withstand daily use in busy shops, resisting wear and maintaining accuracy over time.

Using the JBO Thread Plug Gauge improves workflow by delivering fast, reliable thread checks in a single step. It helps you confirm hole readiness before assembly, reduces rework from out-of-tolerance threads, and supports consistent, high-quality results across production runs. With its tough hardened steel build, it stays reliable through years of use in demanding environments.