Spi 37-146-8 Plug Thread Gage M4x0.7 6H No Go

Product Description

The SPI 37-146-8 is a single-end plug thread gage designed to perform No Go functional inspection of M4x0.7 internal threads to the 6H tolerance class. It verifies that a threaded hole has not been cut undersize or oversize in a way that would allow an out-of-tolerance fastener to pass. The gage body is sized at approximately 0.16 inches in diameter and 1.15 inches in length, weighing 0.044 pounds. A handle is not included and must be sourced separately. Traceability certification is provided to ANSI standards with NIST traceability, making this gage suitable for quality-assurance environments that require documented calibration.

This gage is used in machine shops, manufacturing facilities, and production inspection lines where M4x0.7 threaded holes must be verified before assembly. The No Go member confirms that the internal thread does not exceed the maximum material condition, catching taps that have cut too deep or threads that have been formed incorrectly. Typical users include machinists, quality technicians, and inspectors working with metric fastener specifications on precision components.

Key Features

• No Go gage member for M4x0.7 internal thread inspection
• 6H tolerance class conformance for general-purpose metric threads
• ANSI traceability certification with NIST-traceable standards included
• Single-end design — compact and easy to handle in production environments
• Lightweight at 0.044 pounds, suitable for bench and in-line inspection use

Compatibility

Designed for inspection of M4x0.7 internal threads held to the 6H tolerance class. Use with a standard plug gage handle sized to fit the gage shank diameter.

Installation Notes

This gage is installed into a compatible handle before use — do not attempt to use the gage member bare-handed in a way that could damage the precision ground surface. Clean and lightly oil the gage before and after each use to prevent corrosion and maintain calibration integrity. Handle with care; dropping or impacting the gage against hard surfaces can alter the ground geometry and invalidate its measurements. Periodic recalibration against NIST-traceable masters is recommended per your facility quality plan.