Spi 29-258-1 Class Zz Plus Plug Gage 0.258 in Dia

Product Description

The SPI 29-258-1 is a Class ZZ Plus plug gage used to verify the diameter of bored, drilled, or reamed holes to a nominal size of 0.258 inches. It holds a tolerance of 0.0002 inches, meeting Class ZZ Plus accuracy standards for go/no-go inspection work. The gage is constructed from steel for durability and dimensional stability under repeated use. Machinists, tool and die technicians, and quality control inspectors use this type of gage during in-process and final inspection to confirm that hole diameters fall within specified limits before assembly.

This plug gage is suited for use in machine shops, manufacturing facilities, and precision fabrication environments where hole size verification is a standard step in the inspection process. It is appropriate for checking holes produced by drilling, boring, reaming, or EDM operations in both ferrous and non-ferrous workpieces. The 0.258-inch nominal diameter targets a specific size range common in close-tolerance mechanical assemblies.

Key Features

• Nominal measurement diameter of 0.258 inches for precise hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for accurate go/no-go gauging
• Steel construction provides wear resistance and dimensional stability
• Compact and lightweight at 0.2 pounds for easy single-hand use
• Single-piece package quantity supports individual replacement or spot procurement

Compatibility

Designed as a standard Class ZZ Plus plug gage for use with any go/no-go gage handle or holding fixture that accommodates the 0.258-inch diameter range. Confirm handle size range compatibility before use.

Installation Notes

Plug gages should be handled and stored carefully to prevent nicks, burrs, or corrosion that would affect accuracy. Clean the gage and the hole being checked before use to eliminate chips or debris that can produce false readings. Calibration against a traceable standard is recommended on a regular schedule to verify gage integrity. Only qualified inspection personnel or machinists familiar with go/no-go gauging practice should use precision plug gages in a production environment.