Spi 29-393-6 Class Zz Plus Plug Gage 0.393 in

Product Description

The SPI 29-393-6 is a Class ZZ Plus plug gage designed for precision hole diameter inspection. It measures a nominal diameter of 0.393 inches with a tolerance of 0.0002 inches, making it suitable for close-tolerance go/no-go verification in production and quality-control environments. The gage is constructed from steel for durability and dimensional stability. Machinists, toolroom technicians, and quality inspectors use plug gages like this one to verify that drilled, reamed, or bored holes meet print specifications before parts move to the next stage of production.

This plug gage is used in machine shops, manufacturing facilities, and precision fabrication environments where hole-diameter conformance must be verified to tight tolerances. It is appropriate for use on ferrous and non-ferrous workpieces where a 0.393-inch nominal bore diameter requires certification to Class ZZ Plus standards. The compact size and light weight make it easy to handle during high-volume inspection routines.

Key Features

• Class ZZ Plus accuracy class for precision hole diameter verification
• 0.393-inch nominal measurement diameter
• 0.0002-inch tolerance for close-tolerance go/no-go inspection
• Steel construction for dimensional stability and wear resistance
• Lightweight at 0.2 pounds for comfortable extended use

Compatibility

Designed as an OEM-style Class ZZ Plus plug gage for use in standard toolroom and production inspection applications requiring a 0.393-inch nominal diameter measurement.

Installation Notes

Plug gages should be handled by metrology technicians or trained quality-control personnel following established inspection procedures. Clean the gage and workpiece bore before use to prevent debris from affecting readings or causing premature wear to the gage surface. Store the gage in a protective case away from other tools when not in use to preserve its tolerance integrity. Periodic calibration against a traceable master is recommended to ensure continued measurement accuracy.