Spi 37-183-1 Plug Thread Gage M3x0.5 6H Class Go No Go

Product Description

The SPI 37-183-1 is a double-end plug thread gage used to verify internal metric threads to M3x0.5 specifications at 6H tolerance class. One end carries the Go member and the opposite end carries the No Go member, allowing a technician to confirm both minimum and maximum thread form acceptance in a single tool. The gage ships with a handle included. At 0.066 pounds and a compact profile measuring approximately 2.87 inches in length, it is suited for bench inspection or in-process quality checks on the shop floor. Machinists, quality technicians, and precision parts inspectors use this gage in production and incoming inspection applications.

This gage is designed for checking M3x0.5 internal threaded features in manufactured parts such as fastener bosses, tapped holes in castings, and precision machined components. The 6H tolerance class is the standard fit classification widely specified in metric thread drawings across industrial, aerospace, and mechanical assembly environments. The double-end configuration eliminates the need to handle a separate Go gage and No Go gage during inspection, reducing changeover time at the inspection station.

Key Features

• Double-end design with Go and No Go members on a single handle for efficient thread verification
• M3x0.5 thread size with 6H tolerance class per standard metric thread specifications
• Handle included — no separate handle purchase required
• Traceability certification included, traceable to ANSI and NIST standards
• Compact and lightweight at 0.066 pounds for easy bench or in-process use

Compatibility

Designed for inspection of M3x0.5 internal threaded features conforming to 6H tolerance class specifications. Suitable for use wherever metric thread verification to ANSI and NIST traceable standards is required.

Installation Notes

Thread plug gages are used by quality technicians and machinists and do not require power or mechanical installation. Before use, verify the gage is clean and free of debris, as contamination affects measurement accuracy. Apply light hand pressure only when threading the gage into a part — forcing a No Go member is a sign of an out-of-tolerance condition, not a fitting problem. Store the gage in its protective case when not in use to protect the thread form from damage.