The JBO Thread Ring Gauge (GO) - Metric Fine, Right Hand - M21 x 1 (4h) is a precision inspection tool for confirming external thread diameters. Ideal for quality control labs, production lines, and maintenance workshops, it provides a reliable go/no-go test that quickly verifies components meet the M21 x 1 standard and its 4h tolerance.

Manufactured from hardened steel, it delivers long-lasting wear resistance in busy environments. Its simple, intuitive design makes it easy for operators to identify conforming parts at a glance, helping streamline inspection workflows and reduce rework.

• Precise GO check for metric fine threads: Quickly determine if external threads meet the M21 x 1 right-hand standard with a clear pass/fail indication, speeding up quality inspections.
• Durable hardened steel construction: Built to resist wear and maintain dimensional accuracy over many cycles, ensuring reliable performance in demanding shop conditions.
• User-friendly, quick-to-use design: Easy handling and clear identification of conforming components support efficient quality control and seamless integration into everyday workflows.

Whether you’re setting up a production line or conducting routine inspections, this ring gauge helps you maintain precise sizing, minimize downtime, and ensure threaded parts consistently meet required standards. Its durability and straightforward use translate to faster checks, fewer reworks, and greater confidence in your manufacturing results.