The JBO Thread Plug Gauge (NoGo) – Metric Fine is a precision inspection tool designed specifically for metric fine threads. It targets left‑hand internal threads in an M42 x 1.5 size and 6H tolerance, helping engineers, machinists, inspectors, and workshop professionals quickly verify threaded holes meet exact specifications.

• Metric Fine NoGo validation: Designed to reliably indicate whether a left‑hand M42 x 1.5 thread hole conforms to the 6H tolerance, enabling fast, repeatable hole inspections.
• Durable hardened steel construction: Built from high‑quality materials to resist wear and maintain accuracy through many inspections in demanding environments.
• Left‑hand, 6H compatibility: Specifically matched to left‑hand threads within the M42 x 1.5 size and 6H class, reducing guesswork and ensuring correct part qualification.

This gauge helps you streamline quality control by delivering clear, repeatable checks that confirm hole readiness, minimize rework, and support consistent results across production runs. Its robust design provides long service life in busy shop settings, giving you confidence in every measurement and every part.