Spi 34-214-7 Plug Thread Gage 4-40 6H Single End Go

Product Description

The SPI 34-214-7 is a single-end Go plug thread gage designed to verify internal thread dimensions on 4-40 threaded components. Manufactured from steel, it checks that a tapped hole meets the minimum material condition required for proper thread engagement. This gage conforms to ANSI standards and includes NIST traceability certification, making it suitable for use in quality control environments where documented measurement accuracy is required. It is used by machinists, quality technicians, and precision inspection personnel working with UNC 4-40 threaded fastener applications.

This plug thread gage is used in inspection and production environments where 4-40 threaded holes must be verified before assembly. The Go member confirms that the thread form, pitch diameter, and lead are within acceptable limits for mating fastener insertion. It fits a Size 0 handle, which is sold separately. Applications include light-duty mechanical assemblies, instrumentation, and electronic enclosures where small-diameter threaded features are common.

Key Features

• Go member only — single-end design for pass/fail inspection of minimum material condition
• 4-40 thread size with 6H classification for standard internal thread tolerance
• Steel construction for durability in production inspection use
• NIST traceability certification included for documented quality compliance
• Conforms to ANSI standards
• Compatible with Size 0 handle (handle not included)

Compatibility

Designed for inspection of 4-40 UNC internally threaded holes with a 6H tolerance class. Accepts a Size 0 thread gage handle, sold separately.

Installation Notes

Thread plug gages are installed and used by quality control technicians and machinists — no permanent installation is required. Before use, clean the threaded hole and gage member to remove chips, oil, or debris that could affect the reading. Apply light hand pressure only when inserting the Go member; never force or use tools to drive the gage. Store the gage in a protective case when not in use to preserve calibration integrity.