The JBO Thread Ring Gauge (NoGo) – Metric Fine is a precision inspection tool designed to verify external thread diameters on fasteners and threaded components. Built for engineers, quality control professionals, machinists, and workshop technicians, it provides reliable Go/NoGo checks to confirm adherence to exact M21 x 0.5, right-hand, 6g specifications.

Crafted from hardened steel, this gauge delivers long-lasting performance in demanding environments. Its durable design resists wear and maintains dimensional stability through repeated use, cleaning, and handling on busy shop floors. The straightforward form makes it easy to use during standard inspection routines, helping you quickly identify parts that fall outside tolerance.

• Exact metric fine-thread specification (M21 x 0.5, 6g, Right Hand): Calibrated to the NoGo limit for precise, reliable pass/fail checks, helping prevent out-of-tolerance parts from progressing in production.
• Hardened steel construction: Delivers superior wear resistance and dimensional stability, ensuring consistent accuracy over many inspections and years of use.
• Easy identification of non-conforming threads: Enables fast, unambiguous quality decisions on the shop floor, reducing inspection time and minimizing rework.

This gauge supports efficient quality control workflows by providing clear, repeatable results that you can trust across batches. With its rugged construction and precise sizing, it helps you lock in thread integrity, streamline assembly readiness, and maintain high standards in manufacturing, machining, and maintenance applications.