Spi 37-186-4 Plug Thread Gage M4.5x0.75 6H Double End

Product Description

The SPI 37-186-4 is a double-end plug thread gage used to verify internal metric threads to M4.5x0.75 specification at 6H tolerance class. One end checks the Go condition to confirm the thread accepts a mating fastener; the opposite No Go end confirms the thread is not oversized. A handle is included. This type of gage is a standard tool in machine shops, manufacturing lines, and quality-control environments where threaded holes must meet dimensional specifications before assembly. Machinists, quality technicians, and tool-room personnel are the primary users.

The 37-186-4 is suited for inspecting M4.5x0.75 tapped holes in production or incoming inspection settings. Its double-end design eliminates the need for a separate Go and No Go gage, keeping the inspection process efficient. The 6H classification covers standard-fit internal threads, which represents the most common tolerance class for general-purpose metric fastener applications in both light manufacturing and precision machining environments.

Key Features

• Go and No Go ends on a single double-end design for complete thread verification in one tool
• M4.5x0.75 thread size with 6H tolerance class for standard internal metric threads
• Handle included for immediate use out of the package
• ANSI traceability certification included for quality-system documentation
• Calibrated to NIST-traceable standards

Compatibility

Designed for inspection of M4.5x0.75 internal threads at 6H tolerance class. Suitable for use in any application requiring verification of standard-fit metric tapped holes to that thread specification.

Installation Notes

Thread plug gages require no installation but must be handled carefully to preserve gage accuracy. Always clean the tapped hole and gage members before use to prevent debris from causing false readings. Do not force the No Go end into a thread — hand-tight engagement only. Store the gage in its case when not in use to protect the ground thread surfaces from damage.