Spi 29-988-3 Class Zz Plus Plug Gage 0.988 in Diameter

Product Description

The SPI 29-988-3 is a Class ZZ Plus plug gage used to verify inside diameters with high dimensional accuracy. It measures a nominal diameter of 0.988 inches and holds a tolerance of 0.0002 inches, making it appropriate for go/no-go inspection work in production and quality-control environments. Constructed from steel, this gage is a hand-held instrument used by machinists, quality technicians, and toolroom personnel to confirm bore sizes on machined parts, housings, and other precision components.

Class ZZ Plus plug gages are suited for general-purpose inspection of through-holes and blind bores in manufacturing and maintenance settings. This gage is used when confirming that a drilled, reamed, or bored hole meets dimensional specification before assembly. It is commonly found on shop floors, in inspection departments, and in toolrooms where consistent, repeatable measurement is required without the need for calibrated variable instruments.

Key Features

• Nominal measurement diameter of 0.988 inches for direct go/no-go bore inspection
• Class ZZ Plus tolerance of 0.0002 inches for reliable dimensional verification
• Steel construction provides durability and wear resistance in production environments
• Compact and lightweight at 0.2 pounds for easy single-handed use
• Single-piece packaging — no assembly required out of the box

Compatibility

Designed as a standard Class ZZ Plus plug gage suitable for inspection of bores nominally sized at 0.988 inches across general machining and quality-control applications.

Installation Notes

Plug gages are handled and used by quality technicians and machinists — no power source or mechanical installation is required. Keep the gage clean and lightly oiled when not in use to prevent corrosion on the steel surfaces. Do not force the gage into a bore; improper insertion can damage both the gage and the workpiece, and will compromise measurement accuracy. Store in a protective case away from temperature extremes to maintain dimensional stability.