The JBO Thread Plug Gauge is a precision Go/No-Go tool designed to verify metric fine internal threads. Sized for M21 x 0.75 with 6H tolerance, it helps engineers, machinists, and quality teams quickly confirm threaded holes meet exact specifications before assembly or production.

Built for demanding environments, the gauge features a knurled, easy-grip body and hardened steel construction that resists wear. With clearly defined Go and No-Go orientations, it delivers fast, repeatable readings that reduce inspection time and rework.

• Go/No-Go quick inspection for precise hole sizing: The Go end verifies the hole accepts the minimum material, while the No-Go end confirms it does not exceed the maximum tolerance, delivering fast, unambiguous pass/fail results.
• Metric fine thread compatibility: M21 x 0.75, 6H: Specifically engineered for metric fine thread holes, ensuring accurate checks for components that require tight tolerances and reliable mating.
• Durable, hardened steel construction: Built to withstand daily shop use, resisting wear and keeping measurements consistent over many inspections.

Using this gauge helps you speed up acceptance testing, improve fit consistency across assemblies, and minimize downtime caused by misfitting parts. Its robust design and precise Go/No-Go readings give you confidence to move from inspection to production with fewer surprises.