The JBO Thread Plug Gauge is a UNEF Go-No-Go tool designed to quickly verify the accuracy of left-hand threaded holes sized 1/2 x 28, within the 2B tolerance class. Its precise dimensions help ensure consistent results when inspecting hole size and thread fit, so you can trust every measurement in your quality checks.

Ideal for engineers, machinists, inspectors, and buyers across manufacturing, automotive, and aerospace, this gauge enables fast, repeatable checks on the shop floor or in the quality lab. The simple go/no-go design delivers clear pass/fail feedback, reducing guesswork and helping you prevent misfits and rework in assembly.

• Go/No-Go quick verification: Instantly determine if a threaded hole is within tolerance with a simple pass/fail check, speeding inspections and reducing downstream rework.
• Left-hand UNEF 1/2 x 28 compatibility: Specifically matched for left-handed threads, ensuring accurate checks and preventing reading errors with reverse-thread components.
• Rugged, ergonomic construction: Knurled grip for secure, comfortable handling on busy workstations and reliable ends that maintain alignment for repeatable measurements.

Using this gauge helps streamline quality control, minimize downtime, and ensure that every left-hand thread hole meets specification before assembly. The clear pass/fail indication supports faster, more confident decisions, leading to consistent results and smoother workflows across your production runs.