The JBO Thread Ring Gauge (NoGo) is a precision tool for verifying external UNEF threads on fasteners and machined parts. Specifically designed for left-hand threads in the 7/8 x 20 size and class 2A, this gauge helps inspectors and machinists confirm that components meet Unified thread standards.

Built for daily shop use, the NoGo design provides a clear pass/fail indication, speeding up quality checks and reducing guesswork during assembly. Crafted from hardened steel, it resists wear to maintain accurate measurements over time, even with frequent handling and inspection workloads.

• No-Go Design for Quick Conformity Checks: Quickly identifies non-conforming threads, reducing inspection time and rework by showing a clear pass/fail result for the 7/8 x 20 UNEF left-hand threads.
• Hardened Steel Construction for Durability: Withstands daily use in busy workshops, maintaining strength and accuracy and resisting wear that can drift gauges over time.
• Exact UNEF Left-Hand 7/8 x 20, 2A Class: Ensures measurements align with the standard, providing reliable checks that support correct part fitment and quality control.

Using this gauge streamlines quality control by delivering fast, reliable checks for left-hand external threads. It supports consistent results across manufacturing, automotive, and aerospace workflows, helps prevent misfits and returns, and keeps your threading inspections accurate over the life of the tool.