Spi 37-161-7 Plug Thread Gage M18x1.5 6H No Go

Product Description

The SPI 37-161-7 is a single-end No Go plug thread gage designed to verify M18x1.5 internal threads to the 6H tolerance class. It is used to confirm that a threaded hole has not been cut oversized or out of tolerance, ensuring the mating fastener will not pass freely through an acceptable part. The gage body measures 1.5 inches in length and 0.71 inches in width and depth, and weighs 0.22 pounds. A separate handle is required for use and is not included with this gage. Traceability documentation is provided to ANSI standards with NIST traceability, making this gage suitable for quality-control environments where documentation is required.

This gage is used in machine shops, manufacturing facilities, and maintenance operations where M18x1.5 threaded holes must be inspected to 6H tolerance specifications. Typical applications include inspection of tapped holes in hydraulic fittings, automotive components, and industrial fastener assemblies. The No Go member is used in combination with a separate Go gage to perform a complete thread acceptance check. It is handled by quality inspectors, machinists, and maintenance technicians working to metric thread standards.

Key Features

• No Go member checks that M18x1.5 internal threads are not oversize beyond 6H tolerance limits
• Single-end configuration with a dedicated No Go thread form
• ANSI-compliant with NIST-traceable calibration documentation included
• Compact form factor — 1.5 inches long, 0.71 inches in diameter — fits standard plug gage handles
• Lightweight at 0.22 pounds for easy bench or in-process use
• Handle sold separately, compatible with standard plug gage handle systems

Compatibility

Designed for inspection of M18x1.5 internal threads held to the 6H tolerance class. Handle is not included and must be sourced separately to use this gage member.

Installation Notes

This gage is installed into a standard plug gage handle prior to use — never apply the gage member to a threaded hole without a proper handle, as this risks damage to the gage and inaccurate readings. Ensure the threaded hole being inspected is clean and free of chips, coolant, and debris before gaging. The No Go member should not enter a conforming threaded hole; if it does, the hole is out of tolerance and the part should be rejected. Periodic cleaning and storage in a protective case will help maintain gage accuracy and NIST-traceable calibration status.