Spi 29-780-4 Class Zz Plus Plug Gage 0.78 Inch

Product Description

The SPI 29-780-4 is a Class ZZ Plus plug gage designed for precision hole measurement in manufacturing and inspection environments. It measures bore diameters at 0.78 inches with a tolerance of 0.0002 inches, making it suitable for go/no-go inspection work where tight dimensional control is required. Constructed from steel for durability and dimensional stability, this gage is a standard tool for machinists, quality control technicians, and toolroom professionals who need reliable, repeatable results on the shop floor or in the inspection room.

This plug gage is used in production and quality assurance settings to verify that drilled, reamed, or bored holes meet specified diameter tolerances. It is appropriate for both incoming inspection and in-process checks on metal components. Typical applications include verifying hole sizes on machined parts, fixtures, and assemblies where a 0.78-inch nominal bore diameter is specified.

Key Features

• Class ZZ Plus tolerance class for precision go/no-go inspection
• 0.78-inch nominal measurement diameter
• 0.0002-inch tolerance for tight dimensional verification
• Steel construction for durability and wear resistance
• Single-piece package quantity suits individual technician use

Compatibility

Designed as a standard Class ZZ Plus plug gage suitable for inspection of 0.78-inch nominal bore diameters in general machining and quality control applications.

Installation Notes

Plug gages are handled and used by machinists, toolroom staff, and quality control inspectors — no power tools or electrical shutoff is required. Keep the gage clean and lightly oiled when not in use to prevent corrosion and preserve accuracy. Do not force the gage into an undersized hole, as this can damage the gage or the workpiece. Store in a protective case away from abrasive materials and temperature extremes to maintain dimensional integrity.