Vermont Gage 361129520 Threaded Ring Gage 5/16-18 Unc

Product Description

The VERMONT GAGE 361129520 is a Go-class threaded ring gage used to verify the minimum material condition of external threads. It checks that a threaded fastener or shaft meets the lower tolerance boundary for Class 3A fit, confirming the thread will assemble correctly with a mating part. Made from tool steel, this single-ring gage is manufactured to NIST standards, making it suitable for production inspection, incoming quality control, and calibration lab use. Machinists, quality technicians, and tool room professionals use this gage to maintain tight thread tolerances on precision assemblies.

This gage is sized for 5/16-18 thread, a common Unified National Coarse pitch used across general mechanical assemblies, fastener manufacturing, and precision machined components. Class 3A is a close-tolerance fit classification used where controlled clearance and consistent thread engagement are required. The Go ring gage is used as the first check in a Go/No-Go inspection workflow, confirming the threaded part falls within the acceptable size envelope before the No-Go gage is applied.

Key Features

• Go-class gage checks minimum material condition of 5/16-18 external threads
• Class 3A tolerance classification for close-fit precision thread inspection
• Unified National Coarse thread form for broad fastener and machined-part compatibility
• Single-ring design for straightforward Go inspection workflow
• Tool steel construction for wear resistance and dimensional stability
• Manufactured to NIST standards for traceable measurement accuracy

Compatibility

Designed for inspection of external 5/16-18 UNC Class 3A threads on fasteners, studs, and machined components where Go-class ring gage verification is required.

Installation Notes

Threaded ring gages are handled and stored by quality technicians and tool room personnel, not installed in the field. Before use, clean the gage and the threaded part to remove chips, oil, and debris that can cause false readings. Do not force the gage onto a thread — a Go ring gage should pass under hand pressure only. Store the gage in a protected case away from surfaces that can cause nicks or dimensional distortion.