The JBO Thread Plug Gauge is a precision inspection tool designed for metric fine threads. It’s the reliable choice for machinists, engineers, buyers, tradespeople, hobbyists, and technicians who need fast, accurate checks of threaded holes to ensure perfect mating with screws and inserts.

Built for internal thread verification, this Go/No-Go gauge uses a clear, decisive design to confirm whether a hole meets specification at a glance, reducing guesswork and speeding up quality checks. It’s tailored for right-hand metric threads (M38 x 2) with a 6H tolerance, helping you validate fits with confidence.

• Go/No-Go quick verification: Instantly determine if the internal thread hole is within spec, speeding up inspections and reducing rework.
• Metric fine thread compatibility: Precisely matched to M38 x 2 right-hand threads with 6H tolerance, ensuring accurate gauging for critical assemblies.
• Hardened steel construction: Built to endure daily shop use with wear resistance and long service life, maintaining reliable performance over time.

In daily workflows, the JBO Thread Plug Gauge helps you confirm correct thread engagement, cut inspection time, and maintain consistent results across parts. Its rugged design supports high-volume use in manufacturing, repair, and service environments, giving you a dependable tool you can trust for accurate, repeatable measurements.