Spi 19-491-0 Class Zz Minus Plug Pin Gage 0.491 in

Product Description

The SPI 19-491-0 is a Class ZZ minus plug pin gage machined from steel and used to verify bore and hole dimensions to a high degree of accuracy. Designed to the minus tolerance convention, it measures 0.491 inches in diameter with a tolerance of 0.0002 inches, confirming that a feature is at or just below nominal size. Machinists, tool-and-die makers, and quality control technicians rely on Class ZZ pin gages for go/no-go inspection routines in production and shop environments. The steel construction provides durability and dimensional stability under typical shop conditions.

This pin gage is suited for inspection of drilled, reamed, or bored holes in manufacturing and fabrication settings. It is commonly used in machine shops, aerospace component production, and general metalworking quality assurance. The 0.491-inch diameter targets precision-tolerance bores where verifying hole size against a known standard is required before assembly or further machining operations proceed.

Key Features

• Class ZZ minus tolerance designation for confirming hole size at or just below nominal
• 0.491-inch nominal diameter with a tight 0.0002-inch tolerance
• Steel construction for shop durability and dimensional stability
• Lightweight at 0.2 pounds for easy single-hand use during inspection
• Packaged individually for straightforward inventory and tooling management

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use with compatible pin gage handles and sets sized for 0.491-inch diameter pins in general precision inspection applications.

Installation Notes

Pin gages are handled by quality control technicians and machinists and require no permanent installation. Store the gage in a protective case away from moisture and contaminants to preserve surface finish and dimensional accuracy. Clean the gage and the bore being checked before use to prevent debris from affecting readings. Do not force the pin into an undersized hole, as this can damage the gage surface and compromise measurement integrity.