Spi 19-591-7 Class Zz Minus Plug Pin Gage 0.591 in

Product Description

The SPI 19-591-7 is a Class ZZ minus plug pin gage ground from steel and used to verify bore diameters in precision inspection and quality-control applications. The gage measures 0.591 inches in diameter and holds a tolerance of 0.0002 inches, making it suitable for go/no-go dimensional checks where tight tolerance verification is required. Class ZZ is the standard commercial-grade designation for plug gages used in general inspection work rather than master or reference applications. Machinists, toolmakers, and quality inspectors use this gage to confirm that drilled, reamed, or bored holes meet specified dimensional requirements before parts advance through production.

This pin gage is appropriate for use in machine shops, fabrication facilities, and manufacturing inspection stations handling close-tolerance work. It fits into standard gage handle sets, allowing the inspector to check hole acceptance quickly across production runs. The minus designation means the gage is manufactured to the low side of the nominal diameter, which is the conventional approach for plug gages used in go-gage applications where the gage must enter an acceptable hole without interference.

Key Features

• Class ZZ commercial-grade tolerance class for general inspection use
• 0.591 inches nominal diameter for direct bore verification
• 0.0002 inches tolerance for reliable dimensional conformance checks
• Minus designation — manufactured to the low side of nominal for go-gage applications
• Steel construction for durability in production inspection environments
• Compatible with standard plug gage handles for efficient single-hand operation

Compatibility

Designed as an OEM-style replacement or direct addition to standard plug gage handle sets used in general machining and inspection applications for 0.591-inch nominal bore verification.

Installation Notes

Plug pin gages are installed by qualified machinists or quality-inspection personnel using a standard gage handle sized for the pin diameter range. Clean and deburr the gage and the bore before use to prevent false readings or surface damage. Store the gage in its protective case when not in use to preserve the ground surface finish and maintain calibration integrity. Periodic recalibration against a certified master reference is recommended to confirm the gage remains within its stated tolerance class.