The JBO Thread Plug Gauge is a precision go/no-go inspection tool designed for UNF right-hand threads. Sized No. 6 x 40 with a 3B internal tolerance, it provides a fast, reliable check of threaded holes to ensure they meet the Unified Thread Standard.

Engineered for use in manufacturing, automotive, aerospace, and maintenance environments, this gauge helps inspectors and machinists quickly distinguish conforming from non-conforming threads with a simple plug-and-test method—reducing guesswork and rework in busy shops.

• Go/No-Go quick conformity test: The go and no-go ends let you confirm threaded holes at a glance—the go end should thread in smoothly to spec, while the no-go end should not pass. This speeds inspections and reduces guesswork, especially on high-volume batches.
• UNF Right-Hand 3B with No. 6 x 40 size: Precisely matched to common UNF right-hand threads and a 3B tolerance class, providing accurate, repeatable checks for critical components and ensuring consistent fit across parts.
• Durable, easy-to-handle construction: Machined precision ends, hardened material, and a knurled grip deliver reliable performance in demanding environments, with long tool life and repeatable results across shifts and tasks.

By delivering fast, deterministic thread verification, this gauge helps you speed up inspections, reduce rework, and maintain high-quality assemblies across production runs. Its reliability gives you confidence in every measurement, from prototype work to high-volume manufacturing, ensuring parts fit correctly the first time and minimizing downtime.