The JBO Thread Plug Gauge is a precision inspection tool designed to verify internal metric fine threads. Specifically crafted for M18 x 2 holes with a 6H tolerance, it’s ideal for applications where accurate threading matters and left-handed thread configurations are used.

Its Go/No-Go design lets you perform fast, clear pass/fail checks, helping ensure your components fit together correctly on first assembly. Built with hardened steel, this gauge delivers reliable performance and long service life in busy workshop environments.

• Go/No-Go design for fast, reliable inspection: Quickly determine whether threads are within tolerance, reducing inspection time and minimizing guesswork during assembly or QC checks.
• Left-hand thread compatibility: Specifically engineered for left-handed threaded holes, preventing measurement errors and ensuring accurate gauging every time.
• Hardened steel construction: Durable, wear-resistant body that stands up to daily use, preserving accuracy and extending tool life in demanding shop settings.

Used across assembly lines, maintenance tasks, and quality control workflows, this gauge helps you confirm thread fit with confidence. It supports consistent results, minimizes downtime, and simplifies threaded-hole inspections for both seasoned machinists and weekend hobbyists alike.