The JBO Thread Plug Gauge is a precision inspection tool designed for metric fine threads. It’s specifically sized for M20 x 2 left-hand internal threads, and uses a Go/No-Go design to quickly verify threaded holes during assembly or quality control.

Built for durability in busy workshops, the gauge features hardened steel construction to resist wear and maintain accuracy across many uses, with a 6H internal thread tolerance reference to align with common standards.

• Go/No-Go quick validation: Instantly confirm whether a hole accepts the plug (Go) and whether it stops at the correct depth (No-Go), speeding up setup and inspection with clear pass/fail feedback.
• Left-hand M20 x 2 compatibility (6H): Precisely matched to the M20 x 2 left-hand thread form, using 6H tolerance to deliver consistent, reliable measurements for critical applications.
• Durable hardened steel construction: Built to withstand frequent use in demanding environments, delivering long-lasting performance and stable accuracy over time.

With the JBO Thread Plug Gauge, you gain a reliable, fast, and repeatable way to verify internal threads before assembly. The Go/No-Go checks reduce trial-and-error, helping technicians approve holes on the first pass, cut downtime, and minimize scrap. The left-hand M20 x 2 sizing and 6H tolerance ensure you’re measuring the correct spec, while the hardened steel design keeps the tool dependable through daily shop use.