Spi 29-681-4 Class Zz Plus Plug Gage 0.681 in

Product Description

The SPI 29-681-4 is a Class ZZ Plus plug gage designed for precision go/no-go dimensional inspection of bored holes, machined passages, and manufactured features requiring close tolerance verification. Built from steel, this plug gage measures a nominal diameter of 0.681 inches with a tolerance of 0.0002 inches, providing the accuracy required for quality control work in machine shops, manufacturing facilities, and inspection departments. It is used by machinists, metrology technicians, and quality assurance personnel who need a reliable, repeatable method of verifying hole diameter conformance to print specifications.

This gage is suited for inspection of drilled, reamed, or bored holes in production and job-shop environments where Class ZZ tolerance standards apply. Class ZZ is the most common tolerance class for general-purpose plug gages used in commercial and industrial manufacturing inspection. The 0.681-inch diameter makes it applicable to a specific range of machined bores where that nominal size is called out on engineering drawings. Its compact form and single-piece construction allow for quick, repeatable checks without fixturing.

Key Features

• Nominal measurement diameter of 0.681 inches for precise hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for reliable go/no-go verification
• Steel construction for durability in shop floor and inspection room environments
• Compact single-unit design allows fast, repeatable dimensional checks
• Conforms to Class ZZ standard, the recognized commercial-grade plug gage classification

Compatibility

Designed as a general-purpose Class ZZ plug gage for inspecting machined holes with a nominal diameter of 0.681 inches across standard manufacturing and quality control applications.

Installation Notes

Plug gages are handled and used by metrology technicians and quality control personnel, not installed in a system. Before use, clean the gage and the hole being measured to remove chips, coolant, or debris that could affect accuracy. Do not force the gage through an undersized bore, as this can damage the gage surface and compromise calibration. Store the gage in a protective case away from moisture and temperature extremes to maintain dimensional stability.