The JBO Thread Ring Gauge (GO) - UNC - Left Hand - 2A - 5/16 x 18 is a precision inspection tool designed to verify external threads against the Unified UNC specification. It’s ideal for engineers, machinists, quality inspectors, and maintenance teams who need a fast, reliable way to confirm that threaded components will fit and perform as intended.

Constructed from hardened steel, this GO gauge is built for durability and wear resistance in busy shop environments. Its simple, purpose-built design supports quick insertions and clear results, helping you streamline QC workflows on production floors, in workshops, or in field service.

• Immediate Go/No-Go verification: Provides a fast, decisive check that external threads meet the specified UNC size, enabling quick pass/fail decisions without extra measurement steps.
• Rugged hardened steel construction: Delivers long service life and retains precise dimensions through repeated use, reducing tool replacement and calibration downtime.
• UNC Left-Hand 5/16 x 18 (2A) compatibility: Precisely matched to this thread form and class, ensuring you verify the exact components you manufacture or service with confidence.

Together, these features help you speed up inspections, improve consistency across batches, and reduce costly rework by delivering reliable, repeatable thread verification for UNC left-hand components at 5/16 x 18 with class 2A tolerance.