Spi 29-331-6 Class Zz Plus Plug Gage 0.331 in

Product Description

The SPI 29-331-6 is a Class ZZ Plus plug gage used to verify the internal diameter of precision bores, holes, and machined features. This go/no-go style inspection tool measures at a nominal diameter of 0.331 inches with a tolerance of 0.0002 inches, making it suitable for close-tolerance quality control work on the shop floor or in inspection departments. Constructed from steel, the gage provides repeatable results when checking whether a bore falls within an acceptable range. Machinists, toolmakers, and quality technicians rely on Class ZZ plug gages as an economical, direct-measurement alternative to indicating bore gages for high-volume part verification.

This plug gage is suited for use in manufacturing, machining, and fabrication environments where internal bore acceptance testing is part of the production workflow. Typical applications include verifying drilled, reamed, or bored holes in metal components before final assembly. The 0.331-inch diameter addresses a specific nominal size commonly encountered in precision mechanical work. The gage is well-suited for tool rooms, quality labs, and production lines requiring fast, reliable attribute-style inspection of internal features.

Key Features

• Nominal measurement diameter of 0.331 inches for precise bore verification
• Class ZZ Plus tolerance rating of 0.0002 inches for close-tolerance inspection
• Steel construction for durability and dimensional stability during repeated use
• Compact, lightweight design at 0.2 pounds for easy handling during inspection
• Attribute-style go/no-go measurement method supports fast, high-volume part acceptance

Compatibility

Designed as an OEM-style plug gage for inspecting internal bores and holes with a nominal diameter of 0.331 inches in precision machined components across general manufacturing and toolroom applications.

Installation Notes

Plug gages are handled and used by machinists, toolmakers, and quality control technicians and require no installation. Clean the gage and the bore being inspected before use to prevent debris from affecting measurement accuracy. Store the gage in a protective case away from heat sources and other metal tools to prevent surface damage or dimensional change. Handle with clean, dry hands or inspection gloves to minimize corrosion risk from skin contact with the steel surface.