Spi 29-618-6 Class Zz Plus Plug Gage 0.618 in Dia

Product Description

The SPI 29-618-6 is a Class ZZ Plus plug gage used to verify the inside diameter of holes and bores to a nominal size of 0.618 inches. It delivers a tolerance of 0.0002 inches, providing the precision required for quality control and inspection work in machining, fabrication, and manufacturing environments. The gage is manufactured from steel for durability under regular shop use. Machinists, quality technicians, and toolroom professionals rely on plug gages like this one to confirm that drilled, reamed, or bored features meet print dimensions before parts move to the next stage of production.

This plug gage is suited for go/no-go inspection of holes at the 0.618-inch nominal diameter in both production and toolroom settings. It fits standard inspection workflows where a quick, repeatable check of bore size is needed without the setup time of air or electronic gaging. Typical applications include incoming inspection, in-process quality checks, and final inspection of machined components in job shops, production floors, and precision fabrication facilities.

Key Features

• Nominal measurement diameter of 0.618 inches for direct bore verification
• Class ZZ Plus tolerance of 0.0002 inches for reliable inspection accuracy
• Steel construction for wear resistance and long service life in shop environments
• Single-piece gage format supports fast, repeatable go/no-go checks
• Lightweight at 0.2 pounds for easy one-hand use during inspection

Compatibility

Designed as a standard Class ZZ Plus plug gage for verifying 0.618-inch nominal bore diameters in general machining and inspection applications.

Installation Notes

Plug gages are handled and used by quality technicians and machinists and do not require installation in the traditional sense. Before use, clean both the gage and the bore being checked to remove chips, coolant, and debris that could affect readings. Do not force the gage into an undersize hole, as this can damage the gage surface and compromise accuracy. Store the gage in a protective case away from other tooling to prevent nicks and corrosion.