Spi 19-978-6 Class Zz Minus Plug Pin Gage 0.978 in

Product Description

The SPI 19-978-6 is a Class ZZ minus plug pin gage with a 0.978-inch nominal diameter, manufactured from steel for reliable dimensional inspection in shop and production environments. Class ZZ is the standard tolerance class for general-purpose go/no-go gauging applications. This gage carries a minus tolerance of 0.0002 inches, meaning the actual pin diameter is ground to the lower boundary of the nominal size. Machinists, quality control technicians, and tool room personnel use plug pin gages to verify bore diameters, check hole tolerances, and confirm part conformance to engineering specifications during incoming inspection or in-process measurement.

This pin gage is suited for use in machining, fabrication, and manufacturing inspection workflows where bore size verification at 0.978 inches is required. It is appropriate for both production floor and inspection room use. The steel construction provides durability under repeated insertion cycles. At 0.2 pounds, the gage is lightweight and easy to handle for single-operator use during routine dimensional checks on machined components, castings, or fabricated assemblies.

Key Features

• Class ZZ tolerance class for general-purpose dimensional inspection
• Minus tolerance ground to 0.0002 inches below nominal diameter
• 0.978-inch nominal diameter for precise bore verification
• Steel construction for durability and wear resistance in production use
• Lightweight at 0.2 pounds for easy single-hand operation

Compatibility

Designed as a general-purpose Class ZZ minus plug pin gage for use with standard pin gage handles and sets sized for 0.978-inch diameter pins in shop inspection and quality control applications.

Installation Notes

Pin gages are installed and used by machinists and quality technicians — no permanent installation is required. Before use, clean both the gage and the bore being checked to remove chips, oil, or debris that could affect measurement accuracy. Do not force the gage into an undersized bore, as this can damage the ground surface and alter calibration. Store the gage in a protective case away from other metal tools to prevent nicks or corrosion that would compromise dimensional accuracy.