The JBO Thread Ring Gauge (GO) is a precision tool designed for quality control and precision engineering, enabling quick and reliable verification of external threads. This GO gauge is specifically configured for right-hand metric coarse threads: M39 x 4, with a 6h tolerance, so you can confirm parts meet the exact standard before assembly or finishing.

Manufactured for durability, the gauge uses hardened steel to deliver long tool life and resistance to wear in demanding inspection environments. Its user-friendly design includes a knurled outer edge for a secure grip, making measurements easy and repeatable even when wearing gloves in busy workshops.

• Exact GO gauge for M39 x 4 metric coarse threads: Quickly verify that external threads conform to the M39 x 4 size and 6h tolerance, helping you identify out‑of‑spec parts before they move downstream.
• Hardened steel construction for longevity: Built to withstand frequent use in inspection tasks, delivering durable performance and consistent results over time.
• Ergonomic, easy-to-handle design: Knurled outer edge provides a secure grip for precise insertions and repeatable measurements, even in challenging shop conditions.

Choosing the JBO Thread Ring Gauge (GO) supports streamlined QC workflows, reduces rework, and helps maintain reliable thread reception across production runs. It’s a trusted, standards‑aligned tool for manufacturers, machine shops, and quality laboratories working with metric coarse thread connections.