Vermont Gage 361126040 Threaded Ring Gage 1/4-20 Unc

Product Description

The VERMONT GAGE 361126040 is a single-ring threaded ring gage used to inspect external threads for out-of-tolerance or oversize conditions. This is the No Go member of a Class 3A gage set, designed for use with 1/4-20 UNC thread forms. When a threaded fastener or workpiece passes the Go gage but is rejected by the No Go gage, the external thread falls within the acceptable tolerance band for Class 3A fit. Machined from tool steel, this gage delivers the dimensional stability and wear resistance required for production-floor or inspection-room use. Licensed machinists, quality control technicians, and toolroom personnel use this gage as part of thread verification workflows on machined parts, fasteners, and threaded assemblies.

This gage applies to inspection of 1/4-20 UNC external threads held to Class 3A tolerances, which represent a close-tolerance fit commonly specified for aerospace, precision mechanical, and high-cycle fastener applications. The No Go function confirms that the pitch diameter of the inspected thread does not exceed the maximum material condition limit. It is suited for both incoming inspection of purchased fasteners and in-process verification of machined threaded features in job shop and production environments.

Key Features

• No Go function identifies oversize or out-of-tolerance 1/4-20 UNC Class 3A external threads
• Single-ring design for dedicated No Go inspection use
• Tool steel construction provides hardness and dimensional stability under repeated use
• Calibrated to NIST-traceable standards for reliable measurement traceability
• Compact single-ring format fits standard ring gage handles and holders

Compatibility

Designed for inspection of external 1/4-20 UNC threads to Class 3A tolerance requirements. Intended for use as the No Go member alongside a corresponding Go ring gage of the same thread specification.

Installation Notes

Threaded ring gages are used by quality technicians and machinists and require no installation in the traditional sense. Before use, ensure the gage and workpiece threads are clean and free of chips, oil, or debris that could affect readings. Do not force the No Go gage onto the workpiece — if it requires force to engage, the thread is at or near the tolerance boundary and the workpiece should be re-evaluated. Store gages in a protective case away from impact and temperature extremes to preserve calibration.