Spi 19-308-6 Class Zz Minus Plug Pin Gage 0.308 in

Product Description

The SPI 19-308-6 is a Class ZZ minus plug pin gage machined from steel, used to verify that a hole or bore meets its minimum acceptable size. The gage measures 0.308 inches in diameter and holds a tolerance of 0.0002 inches, making it suitable for go/no-go inspection work in production and quality-control environments. Class ZZ is the standard tolerance class for general-purpose plug gages used in inspection of commercial-grade work. Machinists, toolmakers, and quality technicians rely on this gage to confirm bore dimensions without resorting to variable measurement instruments.

This pin gage is used in machine shops, manufacturing facilities, and maintenance operations where hole size verification is part of a standard inspection routine. The minus designation means the gage is ground to the lower limit of the nominal diameter, functioning as the GO member in a go/no-go gage set for holes at or above the 0.308-inch nominal size. It is appropriate for inspecting drilled, reamed, or bored holes in metal, plastic, and similar materials.

Key Features

• Class ZZ tolerance class for general-purpose commercial inspection
• Minus designation for GO-member application at nominal low limit
• 0.0002-inch tolerance for consistent, repeatable bore verification
• Steel construction for durability and wear resistance in shop environments
• 0.308-inch nominal diameter for direct use or as part of a pin gage set

Compatibility

Designed as a general-purpose Class ZZ minus plug pin gage for inspecting holes and bores with a 0.308-inch nominal diameter in standard commercial manufacturing and quality-control applications.

Installation Notes

Pin gages should be handled with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Before use, confirm the gage and the workpiece are at the same ambient temperature to avoid thermal expansion errors. Store the gage in its protective sleeve or case when not in use to prevent surface damage that would affect measurement accuracy. Calibration should be verified periodically against a traceable reference standard per your facility's inspection plan.