The JBO Thread Ring Gauge (NoGo) - Metric Fine - Left Hand - 6g - M21 x 1 is a precision inspection tool designed to verify external thread diameters on components with metric fine threads. Built for engineers, buyers, tradespeople, hobbyists, and quality teams, it helps confirm that threaded parts meet exact diameter limits at a glance.

Crafted from hardened steel for durability, this NoGo ring gauge withstands daily use in busy workshops, garages, and manufacturing environments. Its robust construction and tight tolerances deliver reliable measurements, supporting fast, confident QC decisions and consistent assembly results.

• NoGo precision limit: Quickly identify non-conforming threads by applying the NoGo limit to confirm parts stay within the specified diameter range, delivering fast pass/fail results during inspection.
• Hardened steel construction: Resists wear, scratches, and deformation, ensuring long service life and stable measurements even in high-volume workflows.
• Left-hand, metric fine compatibility (M21 x 1, 6g): Specifically sized for left-handed fasteners with M21 x 1 thread pitch, 6g class, ensuring accurate checks on the exact components you work with.

Using this gauge helps streamline your quality control, reduces rework, and accelerates production without compromising accuracy. It provides clear, reliable results that support compliance with standards and improve overall threading reliability across your projects.