The JBO Thread Plug Gauge is a precision inspection tool designed to verify internal threads in holes. Built for left-handed UNC threads (5/16 x 18) and finished to Class 2B tolerance, it helps shops across manufacturing, automotive, and aerospace ensure threaded features meet Unified thread standards with reliable, repeatable checks.

Its go/no-go design provides quick, clear pass/fail feedback, so inspectors can confirm proper thread engagement at a glance and move on to the next part without unnecessary downtime.

• Go/No-Go quick verification: Fast, decisive checks that clearly indicate conforming or non-conforming threads, reducing inspection time and guesswork on the shop floor.
• Left-Hand UNC 5/16 x 18, 2B tolerance: Precisely matched to the specified left-handed threads with a tight Class 2B tolerance for consistent, repeatable measurements across production runs.
• Ergonomic, durable construction with color-coded ends: Knurled grip for secure handling and color-coded ends that quickly identify go versus no-go orientation in busy work environments.

This plug gauge supports efficient quality control, helping you maintain tight thread accuracy, shorten inspection cycles, and achieve reliable results in critical assemblies.