Spi 37-144-3 Plug Thread Gage M3x0.5 6H No Go

Product Description

The SPI 37-144-3 is a single-end plug thread gage designed to perform No Go inspection on M3x0.5 internal threads classified to the 6H tolerance standard. This gage is used to verify that a threaded hole has not been cut undersize or left with insufficient clearance — a No Go member that enters the thread indicates a nonconforming part. Built to ANSI standards with NIST traceability certification, the 37-144-3 gives quality control technicians and machinists a reliable, calibration-ready reference tool. Handle is sold separately and is not included. At 0.066 pounds, this is a compact gage suited for bench or floor inspection stations.

The SPI 37-144-3 is intended for use in precision machining, manufacturing, and quality assurance environments where M3x0.5 threaded bores must meet 6H tolerance specifications. Typical applications include incoming inspection, in-process thread verification, and final part acceptance checks on small-diameter metric fastener holes. This gage is appropriate for use in aerospace, automotive, medical device, and general metalworking operations where thread conformance is a controlled requirement.

Key Features

• No Go member confirms M3x0.5 threaded holes are not cut undersize
• 6H classification covers standard tolerance for internal metric threads
• ANSI standard compliance with NIST traceability certification included
• Single-end design for dedicated No Go inspection
• Lightweight at 0.066 pounds for easy handling at the inspection station
• Handle not included — compatible with standard plug gage handles sold separately

Compatibility

Designed for use with standard plug gage handles suitable for the gage member dimensions; handle is not included with this gage. Inspects M3x0.5 internal threads to 6H tolerance class per ANSI standards.

Installation Notes

Thread gages should be handled by a qualified quality technician or metrologist familiar with ANSI thread gage practice. Keep the gage clean and lightly oiled to prevent corrosion and ensure accurate readings. Do not force the gage member into a threaded bore; hand pressure only is appropriate for plug gage inspection. Store the gage in a protective case away from temperature extremes to maintain calibration integrity.