Spi 29-078-3 Class Zz Plus Plug Gage 0.078 Inch

Product Description

The SPI 29-078-3 is a Class ZZ Plus plug gage used to verify bore and hole diameters in precision machining and inspection applications. Sized at 0.078 inches in diameter with a tolerance of 0.0002 inches, this gage provides the tight accuracy required for go/no-go inspection of small-diameter features. Constructed from steel for durability and dimensional stability, it is a standard tool in quality control environments where consistent, repeatable measurement is critical. Machinists, tool and die makers, and quality inspectors rely on plug gages like this one to confirm that drilled, reamed, or bored holes fall within specification.

This plug gage is suited for use in precision manufacturing, job shops, and inspection departments working with small-bore components. It is appropriate for both production-floor verification and incoming inspection of machined parts. The 0.078-inch nominal diameter makes it well matched to applications involving small pilot holes, pin bores, and similar close-tolerance features common in mechanical assemblies and instrument components.

Key Features

• Class ZZ Plus tolerance grade for reliable go/no-go hole inspection
• 0.078-inch nominal diameter for small-bore measurement
• 0.0002-inch tolerance for precise dimensional verification
• Steel construction provides long service life and dimensional stability
• Compact, single-piece design for easy handling during inspection

Compatibility

Designed as a standard Class ZZ Plus plug gage for verifying 0.078-inch nominal diameter holes and bores in machined components across general manufacturing and inspection applications.

Installation Notes

Plug gages are used by quality control technicians and machinists and require no permanent installation. Clean the gage and the bore being checked before use to prevent contamination from affecting the measurement result. Handle with care to avoid dropping or striking the gage, as impact damage can alter the precision ground diameter. Store in a protective case away from moisture and temperature extremes to maintain calibration integrity.