Spi 23-131-6 Threaded Ring Gage 5-40 Class 2A Go No Go

Product Description

The SPI 23-131-6 is a double-ring threaded ring gage designed to inspect external threads to the No. 5-40 UNC thread standard at Class 2A tolerance. The set includes both a Go ring and a No Go ring in a single double-ring body, allowing technicians to verify that machined or fastener threads fall within the acceptable tolerance range in one efficient check. Constructed from tool steel, this gage delivers the hardness and dimensional stability required for consistent, repeatable gauging on the shop floor or inspection bench. It carries NIST traceability certification, supporting quality-system documentation requirements in ISO or AS9100-registered environments.

This gage is suited for use in precision machining, manufacturing inspection, and fastener production environments where external thread acceptance criteria must be verified against ANSI or unified thread standards. Machinists, quality technicians, and inspection personnel use Class 2A Go/No Go ring gages to confirm that externally threaded components such as screws, studs, and bolts will assemble correctly with mating Class 2B internal threads. The 5-40 size targets small-diameter machine screw threads common in instrument, electronic, and light mechanical assemblies.

Key Features

• Go and No Go rings combined in a single double-ring body for efficient thread acceptance testing
• Class 2A tolerance classification for standard-fit external thread inspection
• Tool steel construction for hardness and long service life under repeated use
• NIST traceability certification included to support documented quality systems
• Compact and lightweight at 0.118 pounds for easy bench or portable use

Compatibility

Designed for inspection of No. 5-40 UNC external threads manufactured to Class 2A tolerance per unified thread standards.

Installation Notes

Thread ring gages are inspection tools used by machinists and quality technicians — no installation in a system is required. Store gages in a clean, dry environment and handle them carefully to avoid nicks or drops that can alter calibration. Gages should be periodically recalibrated against certified setting plugs in accordance with your facility quality plan. Do not force the gage onto a thread; if it does not turn freely by hand, the part is out of tolerance.