Spi 37-143-5 Plug Thread Gage M2.5x0.45 6H No Go

Product Description

The SPI 37-143-5 is a single-end, No Go plug thread gage designed to verify M2.5x0.45 internal threads to the 6H tolerance class. It is used to confirm that a tapped hole does not accept an oversized condition, ensuring threads fall within the correct tolerance window before assembly. The gage is supplied without a handle, so a compatible separate handle is required for use. At 0.044 pounds, it is a compact, precision tool built for quality-control applications in machining, manufacturing, and inspection environments. Traceability certification to ANSI standards with NIST traceability is included.

This gage is suited for inspection of M2.5x0.45 tapped holes in precision machined components, small fastener assemblies, and electronic or mechanical subassemblies where tight thread tolerances are critical. The 6H classification makes it appropriate for standard-fit metric threaded applications. Machinists, QC inspectors, and toolroom technicians are the primary users. It is a single-function No Go gage, meaning it is used alongside a separate Go gage to complete a full thread acceptance check.

Key Features

• No Go plug gage rejects tapped holes that exceed the 6H upper tolerance limit
• M2.5x0.45 thread specification for small-diameter metric threaded holes
• Single-end design for dedicated No Go inspection without Go gage interference
• ANSI traceability certification with NIST-traceable standards included
• Lightweight at 0.044 pounds for easy handling during bench inspection
• Handle not included — compatible separate handle required for operation

Compatibility

Designed for inspection of M2.5x0.45 internal threads manufactured to the 6H tolerance class per ANSI and NIST-referenced standards.

Installation Notes

Thread plug gages are used by machinists and quality control inspectors — no installation is required, but proper gage technique is essential for accurate results. A separate compatible handle must be attached before use. Never force the No Go gage into a hole; it should not enter a correctly tapped thread. Store the gage in a protective case and calibrate or re-certify at intervals appropriate to your shop quality system.