Spi 19-540-4 Class Zz Minus Plug Pin Gage 0.54 in

Product Description

The SPI 19-540-4 is a Class ZZ minus plug pin gage machined from steel, designed to verify that a hole or bore meets its minimum acceptable size. The gage measures 0.54 inches in diameter and holds a tolerance of 0.0002 inches, making it suitable for go/no-go inspection workflows in machining, fabrication, and quality-control environments. Class ZZ is the standard tolerance class for general-purpose inspection gages used in production settings. Machinists, quality technicians, and tool-room professionals rely on this type of gage to confirm dimensional conformance without specialized measurement equipment.

This plug gage is used in production inspection and quality assurance applications where hole diameter verification is required. It is appropriate for both light manufacturing and general machine-shop use. The minus designation means the gage is ground to the lower end of the tolerance band, functioning as a no-go member in a gage pair or as a standalone lower-limit check. It is suited for use with ferrous and non-ferrous workpieces across a range of industries including automotive, aerospace component supply, and general fabrication.

Key Features

• Class ZZ tolerance class for general-purpose production inspection
• Minus designation provides lower-limit no-go gaging function
• 0.54 inch nominal diameter with 0.0002 inch tolerance
• Steel construction for durability in shop environments
• Compact form factor suited for handheld go/no-go inspection

Compatibility

Designed as a general-purpose Class ZZ minus plug gage for verifying 0.54 inch nominal bore diameters in standard production inspection applications.

Installation Notes

Plug pin gages are handled by quality technicians and machinists during inspection operations. Clean the gage and workpiece bore before use to prevent contamination from affecting readings. Store the gage in its protective case when not in use to preserve the ground surface finish and dimensional accuracy. Do not force the gage into a bore, as this can damage the gage surface and introduce measurement error.