Spi 37-112-0 Plug Thread Gage M8x1 6H Class Go

Product Description

The SPI 37-112-0 is a single-end Go plug thread gage designed to verify internal M8x1 threads to the 6H tolerance class. It confirms that a tapped hole meets the minimum material condition for thread form, pitch diameter, and lead, allowing a conforming fastener to assemble without interference. The gage body measures 1.5 inches in length with a 0.31-inch diameter and weighs approximately 0.066 pounds. It ships without a handle, so a compatible handle must be sourced separately. ANSI traceability certification is included, and the instrument is calibrated to NIST standards, supporting documented quality control programs on the shop floor or in the field.

This gage is used wherever M8x1 tapped holes require inspection against 6H class tolerances. Typical applications include manufacturing inspection, incoming parts verification, and in-process quality checks on machined components in metalworking, automotive, aerospace, and general industrial environments. Machinists, quality technicians, and tool-and-die professionals use this type of gage to accept or reject tapped features before assembly. The single-end Go configuration is commonly paired with a separate No-Go gage when full limit inspection is required.

Key Features

• Go member checks M8x1 internal threads to 6H tolerance class
• Single-end design for dedicated Go inspection without No-Go risk
• ANSI traceability certification included for quality documentation
• Calibrated to NIST standards for traceable measurement
• Compact 1.5-inch length and 0.31-inch diameter fits standard plug gage handles
• Handle not included — compatible with standard interchangeable handle systems

Compatibility

Designed for use with standard plug gage handles that accept the 0.31-inch diameter gage member. Intended for inspection of M8x1 internally threaded features manufactured to 6H class tolerances per ANSI and ISO thread standards.

Installation Notes

Thread gages should be installed into a compatible handle before use. Always inspect the gage member for nicks or wear before gauging, as damage to the thread form will produce unreliable results. Do not force the Go member through a tapped hole — hand-rotation under light axial pressure is the correct technique. Store the gage protected from corrosion and impact to maintain calibration integrity.