The JBO Thread Plug Gauge (NoGo) is a precision inspection tool designed to verify internal metric coarse threads. It is specifically sized for M42 x 4.5 left-hand threads and 6H tolerance, making it an ideal choice for machine shops, quality teams, and precision engineers who need reliable hole checks. Use it to confirm that threaded holes will accept fasteners and perform as intended in assemblies across automotive, industrial, and equipment applications.

Crafted from durable hardened steel, this gauge is built to withstand the demands of busy workshops. The knurled body provides a secure grip for precise alignment, while its compact form fits easily into your QC toolkit. With clear, repeatable measurements, it delivers long-lasting performance you can trust for routine go/no-go checks.

• Rugged hardened steel construction: Built to withstand daily use in demanding environments, delivering long-lasting accuracy and reliability.
• NoGo sizing for M42 x 4.5 left-hand threads: Provides clear, pass/fail checks to ensure threads meet their tolerance and will assemble correctly.
• User-friendly knurled design for fast checks: Easy to grip and align, enabling quick, repeatable inspections with minimal setup, reducing downtime.

In daily use, the JBO plug gauge helps streamline quality control and assembly workflows by delivering fast, repeatable thread inspections. It reduces rework by catching out-of-tolerance holes early and supports consistent, reliable threaded connections across parts and equipment. With durable construction and precise sizing, you can trust it as a standard instrument in your manufacturing or workshop toolkit.