Spi 23-207-4 Threaded Ring Gage 1-12 Class 2A Go No Go

Product Description

The SPI 23-207-4 is a double-ring threaded ring gage designed to verify the dimensional accuracy of 1-12 externally threaded fasteners and components. It includes both a Go ring and a No Go ring in a single tool, allowing technicians to confirm that a threaded part falls within the acceptable tolerance range for Class 2A fits in a single inspection sequence. Constructed from tool steel for durability and dimensional stability, this gage meets NIST traceability standards and ships with a NIST traceability certification. It is used in quality control and inspection workflows across manufacturing, machining, and mechanical assembly environments.

This gage is suited for inspecting 1-12 Unified National thread forms on bolts, studs, and other external threaded workpieces requiring Class 2A tolerance verification. Class 2A is the standard fit classification used for the majority of general-purpose commercial fasteners. The double-ring configuration eliminates the need to handle separate Go and No Go gages, streamlining inspection on the shop floor or at a receiving station.

Key Features

• Double-ring design combines Go and No Go gages in a single unit
• Thread size: 1-12 Unified National thread form
• Class 2A classification for standard commercial fastener tolerance verification
• Tool steel construction for long service life and dimensional stability
• NIST traceability certification included with each unit
• Meets NIST standards for calibrated inspection tooling

Compatibility

Designed for inspection of externally threaded components with a 1-12 thread size and Class 2A tolerance classification. Suitable for use in general machining, manufacturing, and mechanical assembly quality control applications.

Installation Notes

Threaded ring gages are handled and applied by quality control technicians, machinists, and inspection personnel. The part being inspected should be free of chips, burrs, and cutting fluid before gaging. Apply the Go ring first; it should pass over the full thread length under its own weight or with minimal hand pressure. The No Go ring should not fully engage. Store gages in a protective case away from impact and temperature extremes to maintain calibration integrity.