The JBO Thread Plug Gauge is a precision tool built for metric fine threads, specifically designed to verify M4 x 0.5 right‑hand threaded holes. Its Go/No‑Go design lets you quickly confirm whether a hole will accept a mating part, helping assemblies go together smoothly and without guesswork.

Manufactured from hardened steel for durable, reliable performance in busy workshops, this gauge maintains accuracy after repeated use. The 4H tolerance specification ensures consistent results across inspections, making it an essential addition for engineers, machinists, quality inspectors, and maintenance teams who demand dependable thread checks in demanding environments.

• Fast Go/No-Go inspection: Quickly determine if a hole meets the required M4 x 0.5 right‑hand thread, reducing inspection time and minimizing rework.
• Metric fine thread accuracy M4 x 0.5, right-hand, 4H: Ensures precise thread dimensions and reliable fit with standard fasteners in critical assemblies.
• Hardened steel, durable construction: Built to withstand daily shop use, resist wear, and maintain long‑term accuracy for repeated inspections.

Using the JBO Thread Plug Gauge streamlines quality control and assembly workflows. It helps you confirm thread suitability at a glance, save time during inspections, and achieve consistent, repeatable results across production runs and maintenance tasks.