The JBO Thread Plug Gauge is a precision tool designed for quick, reliable inspection of internal threads. Sized for No. 2 x 56 and designed for left-hand UNC threads, it helps machinists, inspectors, and assembly teams verify hole threads meet Unified standards with confidence.

With its Go/No-Go design, this gauge provides fast, unambiguous pass/fail feedback, allowing you to identify conforming and non-conforming threads at a glance and keep production moving.

• Go/No-Go UNC left-hand thread checks: Quickly determine whether internal threads meet spec, reducing inspection time and ensuring proper fit during assembly.
• 2B internal thread tolerance: Delivers precise, standardized sizing that aligns with Unified thread specifications for consistent results across parts.
• Durable, dual-end design: Built for repeated use with a secure grip and robust ends, supporting reliable measurements in busy shop environments.

Using the JBO Thread Plug Gauge helps you speed up inspections, minimize rework, and improve overall thread quality across manufacturing, automotive, and aerospace applications. It provides clear, dependable feedback that you can trust for every part and every build.