The JBO Thread Plug Gauge is a precision go-no-go tool designed to verify internal UNF threads in holes and threaded features. This left-hand variant is sized for 1 1/4 x 12 UNF holes and rated for 2B tolerance, providing quick, decisive checks that help ensure every part meets Unified thread standards. Its compact, easy-to-handle design makes it suitable for production floors, automotive service bays, aerospace maintenance, and serious hobbyist workshops.

Constructed with a knurled metal body for secure grip, the gauge features go and no-go ends that clearly indicate pass or fail at a glance. The durable construction and precise end profiles support reliable measurements across repeated inspections, reducing rework and downtime while promoting consistent thread quality.

• Go/No-Go design for fast, confident inspections: Instantly verify whether a hole is within tolerance—no guesswork, no additional tools needed.
• Left-hand UNF 1 1/4 x 12 with 2B tolerance: Specifically calibrated for left-hand threads, delivering consistent fit checks for critical components.
• Rugged, knurled construction for lasting reliability: Durable metal body with a textured grip that stands up to daily shop use and helps you handle the gauge securely.

With the JBO Thread Plug Gauge, you can streamline thread inspection, minimize downtime, and improve overall part quality. The go/no-go approach provides clear, repeatable results, while the left-hand 1 1/4 x 12 size and 2B tolerance ensure you’re testing exactly the right threads. A durable, easy-to-grip design means this gauge stays reliable through daily use in busy shops, helping you deliver consistent, quality assemblies—whether you’re building engines, housings, or other precision components.