Spi 23-197-7 Threaded Ring Gage 3/4-20 Class 2A Go No Go

Product Description

The SPI 23-197-7 is a double-ring threaded ring gage designed to verify the dimensional accuracy of external threads. It provides both Go and No Go gauging in a single tool, allowing technicians to confirm that a threaded workpiece falls within the acceptable tolerance range for Class 2A fit. Machined from tool steel and traceable to NIST standards, this gage is built for reliable, repeatable inspection in shop and field environments. It measures 3/4-20 thread size and is a standard instrument for quality control in precision machining, fabrication, and mechanical assembly work.

This gage is suited for inspection of externally threaded fasteners, shafts, fittings, and components where a 3/4-20 unified thread form is specified. Class 2A classification corresponds to the most common tolerance class for commercial fasteners and general-purpose threaded parts. Machinists, quality control inspectors, and tool-room technicians use this type of double-ring gage to accept or reject threaded components during in-process or final inspection. The NIST traceability certification supports use in ISO-compliant and AS9100 quality environments.

Key Features

• Go and No Go gauging in a single double-ring tool for complete Class 2A thread verification
• 3/4-20 thread size for unified thread form inspection
• Machined from tool steel for hardness and wear resistance in production environments
• NIST-traceable calibration certification included for quality system compliance
• Compact form factor suitable for bench inspection and in-line quality checks

Compatibility

Designed for inspection of externally threaded components with a 3/4-20 unified thread form manufactured to Class 2A tolerance specifications.

Installation Notes

Threaded ring gages are precision instruments and should be handled and stored carefully to prevent damage to the gauging surfaces. Keep the gage clean and lightly oiled when not in use to prevent corrosion. Periodic recalibration against a certified master setting plug is recommended to maintain measurement accuracy over time. Do not force the gage onto a workpiece — if the Go ring does not advance freely, the thread is out of tolerance.