The JBO Thread Plug Gauge is a precision left-hand UNC go-no-go tool sized for 1/4 x 20 threads with a 2B tolerance class. It enables quick, reliable checks of threaded holes to ensure they meet the Unified Thread Standard.

Designed for engineers, machinists, inspectors, and buyers, this gauge supports consistent quality across manufacturing, automotive, and aerospace applications by identifying conforming vs non-conforming threads with a simple go/no-go test.

• Go/No-Go System for Fast Conformity Checks: Quickly determine whether a thread hole meets spec, reducing inspection time and avoiding misfits.
• Left-Hand UNC 1/4 x 20, 2B Class: Ensures compatibility with common left‑hand threads and standard tolerance for reliable, repeatable results.
• Durable, Precision-Engineered Body: Built for repeated use in busy environments with consistent measurements and long tool life.

This gauge helps streamline quality control by providing fast, objective pass/fail results for 1/4 x 20 left‑hand UNC threads. With repeatable measurements and durable construction, you’ll reduce rework, increase throughput, and gain confidence in every assembly you validate.