Spi 29-368-8 Class Zz Plus Plug Gage 0.368 in Dia

Product Description

The SPI 29-368-8 is a Class ZZ Plus plug gage used to verify the diameter of drilled, reamed, or bored holes to a nominal size of 0.368 inches. It holds a tolerance of 0.0002 inches, making it suitable for go/no-go inspection work in production and quality-control environments. The steel construction provides durability for repeated use in shop-floor conditions. Machinists, toolmakers, and quality inspectors use plug gages like this one to confirm that a finished bore meets dimensional requirements before parts move to the next stage of assembly.

Class ZZ Plus plug gages are used in light-to-medium inspection applications where a tighter tolerance than standard Class ZZ is required. Typical scenarios include checking machined components, castings, or fabricated parts in job shops, manufacturing facilities, and maintenance operations. The 0.368-inch size corresponds to a common drill or reamer dimension used in general metalworking and precision assembly work. Individual-piece packaging makes this suitable for one-time tooling orders as well as replenishment of existing gage sets.

Key Features

• Class ZZ Plus tolerance class for tighter dimensional verification than standard Class ZZ
• 0.368-inch nominal measurement diameter for compatibility with common drill and reamer sizes
• 0.0002-inch tolerance provides reliable go/no-go inspection accuracy
• Steel construction for durability under repeated shop-floor use
• Compact and lightweight at 0.2 pounds for easy single-hand operation

Compatibility

Designed as an OEM-style replacement or direct addition to Class ZZ Plus plug gage sets used in general metalworking and precision machining inspection applications at the 0.368-inch bore size.

Installation Notes

Plug gages require no installation in the traditional sense, but proper handling is critical to maintaining accuracy. Always clean the gage and the bore being checked before use to remove chips, coolant, or debris that can affect readings. Store the gage in a protected case or sleeve when not in use to prevent surface damage. Calibration should be verified periodically against a certified master to ensure the gage remains within tolerance over time.