Spi 34-338-4 Double End Go No Go Plug Thread Gage

Product Description

The SPI 34-338-4 is a double-end plug thread gage used to inspect and verify internal threads machined to a 0-80 thread size and 3B tolerance class. One end carries the Go member and the opposite end carries the No Go member, allowing a machinist or quality inspector to confirm both minimum and maximum thread acceptance limits in a single tool. The gage is constructed from steel for wear resistance and dimensional stability under repeated use. A handle is included, and the gage ships with NIST traceability certification, supporting quality management systems that require documented measurement standards.

This gage is used in precision machining, aerospace, electronics manufacturing, and any production environment where 0-80 miniature fastener threads must be verified before assembly. The 0-80 thread is among the finest standard unified thread sizes and appears frequently in instrument hardware, optical assemblies, and small electronic enclosures. The double-end design reduces tool changeover time on the inspection bench or production floor.

Key Features

• Double-end design with Go and No Go members on a single gage body
• Verifies 0-80 thread size to 3B tolerance class per unified thread standards
• Steel construction for dimensional stability and long service life
• NIST traceability certification included for quality system compliance
• Handle included — no separate handle purchase required

Compatibility

Designed for inspection of internal 0-80 unified threads machined to a 3B tolerance class.

Installation Notes

Thread gages are inspection tools and do not require installation in a mechanical system. Apply a light thread gage lubricant before use to reduce wear and protect the gage members. The Go member should pass through the threaded hole under its own weight with minimal force; the No Go member should not fully engage. Store the gage in a protective case away from other metal tooling to prevent contact damage to the thread form.