Spi 29-085-8 Class Zz Plus Plug Gage 0.085 in

Product Description

The SPI 29-085-8 is a Class ZZ Plus plug gage used to verify the diameter of machined holes and bores to tight dimensional tolerances. It measures at a nominal diameter of 0.085 inches with a tolerance of 0.0002 inches, making it suitable for precision inspection work in machine shops, tool rooms, and manufacturing environments. The steel construction provides durability and dimensional stability under repeated use. Machinists, quality control technicians, and toolmakers use plug gages like this one as part of go/no-go inspection routines to confirm that drilled, reamed, or bored holes fall within specification.

This plug gage is suited for inspecting small-diameter holes in precision components across a range of industries including aerospace, automotive, and general metalworking. At 0.085 inches nominal diameter, it addresses a fine end of the bore-measurement range where calipers and standard measuring tools lack sufficient resolution. It is typically used in a fixed-limit inspection process, where the gage is passed into or held against a feature to confirm dimensional acceptance without requiring a readout instrument.

Key Features

• Nominal measurement diameter of 0.085 inches for small-bore inspection
• Class ZZ Plus tolerance rating of 0.0002 inches for precision go/no-go applications
• Steel construction for dimensional stability and long service life
• Compact and lightweight at 0.2 pounds for easy bench or in-process use

Compatibility

Designed as an OEM-style precision inspection tool for use in any fixed-limit go/no-go gauging application requiring a 0.085-inch nominal bore diameter check.

Installation Notes

Plug gages are handled and used by machinists and quality control technicians during inspection — no power source or installation is required. Before use, clean the gage and the bore being checked to remove chips, coolant, or debris that could affect the measurement result. Do not force the gage into an undersized hole, as this can damage the gage surface and compromise its accuracy. Store the gage in a protective case away from other metal tooling to prevent nicking or wear to the ground surface.