The JBO Thread Plug Gauge is a precision Go/No-Go tool built for metric fine threads. This left‑hand version checks M29 x 1 holes to ensure they meet exact size and pitch, helping parts fit together with confidence.

Ideal for engineers, machinists, quality control staff, and shop hobbyists, it speeds up threaded-hole inspection by delivering a quick pass/fail verdict—so you can move to the next step without second guessing.

• Go/No-Go design for fast, reliable checks: Instantly confirms whether a hole is within tolerance, reducing inspection time and preventing misfits in assemblies.
• Rugged hardened steel construction: Built to withstand daily use, resist wear, and maintain accuracy over long service life.
• Metric fine thread with 6H tolerance and left-hand orientation (M29 x 1): Precisely matched to fine-pitch holes and left-hand threads, ensuring exact fit and reliable results in specialized applications.

With its focused 3-point check and sturdy build, the JBO Thread Plug Gauge helps you tighten quality across every job. It speeds up the setup and inspection process, reduces guesswork, and supports consistent, repeatable thread quality in production, maintenance, and repair tasks.