Spi 19-989-3 Class Zz Minus Plug Pin Gage 0.989 in

Product Description

The SPI 19-989-3 is a Class ZZ minus plug pin gage with a nominal diameter of 0.989 inches and a tolerance of 0.0002 inches. It is used to verify that a hole or bore meets its dimensional specification by checking for minimum acceptable size. The minus designation means the gage is manufactured at the low end of the nominal dimension, making it a go-type reference tool for inspection workflows. The steel construction provides the hardness and wear resistance required for repeatable use in machine shops, fabrication facilities, and quality control environments. Machinists, QC inspectors, and tool-and-die technicians are the primary users.

This pin gage is suited for inspection of precision-drilled, reamed, or bored holes in manufacturing and metalworking applications. It fits into standard pin gage handle sets for use at the workbench or on the production floor. The 0.989-inch nominal diameter positions it for use with larger bore features common in industrial component inspection. It is appropriate for both incoming inspection of raw materials and in-process verification during machining operations.

Key Features

• Class ZZ tolerance classification for go-type inspection gaging
• Nominal diameter of 0.989 inches for larger bore applications
• Tolerance of 0.0002 inches for precise dimensional verification
• Steel construction provides hardness and long service life
• Minus designation confirms minimum acceptable hole size
• Compatible with standard pin gage handles for easy integration into existing gage sets

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use with compatible pin gage handles and sets sized for the 0.989-inch diameter range.

Installation Notes

Pin gages are installed by hand into the bore being inspected — no power tools or torque specifications apply. Keep the gage clean and lightly oiled when stored to prevent corrosion and dimensional distortion. Handle the gage by the body rather than the contact surfaces to avoid introducing wear or contamination. Inspection should be performed in a temperature-controlled environment when close tolerances are critical, as thermal expansion can affect readings.