Spi 29-779-6 Class Zz Plus Plug Gage 0.779 in

Product Description

The SPI 29-779-6 is a Class ZZ Plus plug gage used to verify bore and hole diameters to a precise measurement of 0.779 inches with a tolerance of 0.0002 inches. Machined from steel, this go/no-go style gage provides a straightforward pass-fail check on inside diameter dimensions during production inspection or incoming quality control. It is sized and classed for general-purpose inspection work where ZZ-class tolerances meet the required accuracy standard. Metrologists, machinists, and quality technicians use plug gages like this one to confirm that drilled, bored, or reamed features meet print specifications without the need for variable measurement instruments.

This gage is suited for use in machine shops, manufacturing facilities, and quality inspection departments working with workpieces that require a 0.779-inch nominal bore diameter. It fits standard gage handle holders compatible with its shank size, making it easy to integrate into an existing set of plug gage tooling. The steel construction holds up well under repeated use in shop environments. It is appropriate for both production-line inspection and tool-room verification tasks where Class ZZ Plus accuracy is specified.

Key Features

• 0.779-inch nominal diameter for direct bore inspection at that dimension
• Class ZZ Plus tolerance of 0.0002 inches for general-purpose inside-diameter checking
• Steel construction for durability through repeated inspection cycles
• Compatible with standard plug gage handle holders for easy use
• Compact and lightweight at 0.2 pounds for handheld operation

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any application requiring Class ZZ Plus inspection of a 0.779-inch nominal bore diameter using a standard plug gage handle system.

Installation Notes

Plug gages should be handled with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Store the gage in its protective case when not in use to avoid nicks or surface damage that could affect gage accuracy. Before use, verify the gage is at thermal equilibrium with the workpiece, typically 68 degrees F per metrology standards, to eliminate thermal expansion measurement error. Periodic recalibration against a traceable standard is recommended to confirm the gage remains within tolerance.