The JBO Thread Ring Gauge (NoGo) - Metric Coarse - Right Hand - 6h - M39 x 4 is a precision inspection tool used to verify the external thread diameters of fasteners and threaded components. It’s designed for engineers, machinists, quality teams, and workshop professionals who need quick, reliable checks to confirm parts meet your specifications.

Crafted from hardened steel and engineered for durability, this NoGo gauge withstands daily wear in busy work environments while preserving accurate measurements. Its meticulous design supports effortless inspection and helps you identify non-conforming parts fast, reducing rework and downtime.

• Fast Go/NoGo verification: Quickly determine whether external threads meet the M39 x 4 coarse-thread standard (6h) and spot non-conforming components, speeding up quality checks and reducing production delays.
• Durable hardened steel construction: Built to endure frequent handling and busy workshop use, delivering long tool life and stable performance over time.
• Precisely machined to 6h, M39 x 4: Exact dimensions ensure consistent, repeatable measurements across batches, making cross-checks with mating parts straightforward and reliable.

Using the JBO NoGo Ring Gauge fits naturally into quality control workflows, helping you confirm fitment accuracy, maintain tight tolerances, and improve overall production reliability. With durable construction and precise dimensions, it supports faster inspections, fewer rejects, and increased confidence in every threaded assembly.