Spi 29-425-6 Class Zz Plus Plug Gage 0.425 in Dia

Product Description

The SPI 29-425-6 is a Class ZZ Plus plug gage designed for go/no-go dimensional inspection of machined bores and holes with a nominal diameter of 0.425 inches. Built to Class ZZ Plus tolerances of 0.0002 inches, it provides reliable pass/fail verification during production and incoming inspection workflows. The gage is manufactured from steel for durability and dimensional stability under shop-floor conditions. Machinists, quality technicians, and tool-and-die professionals use plug gages like this one to confirm that drilled, reamed, or bored features meet print tolerances without requiring a CMM or variable measurement instrument.

This gage is suited for use in machine shops, fabrication facilities, and quality inspection departments where hole diameter conformance must be verified quickly and repeatably. It is appropriate for both production-floor spot checks and receiving inspection of precision components. The 0.425-inch nominal diameter covers a common bore size found in general machining and light manufacturing applications. The compact form factor and steel construction make it practical for high-frequency use at the machine or inspection bench.

Key Features

• Class ZZ Plus tolerance of 0.0002 inches for precise go/no-go hole inspection
• Nominal measurement diameter of 0.425 inches
• Steel construction for wear resistance and long service life
• Compact plug gage form for fast, repeatable bore verification
• Single-piece package quantity for individual tooling procurement

Compatibility

Designed as an OEM-style inspection tool for verifying bores and holes at a nominal diameter of 0.425 inches in standard go/no-go gage applications across general machining environments.

Installation Notes

Plug gages are handled and used by machinists and quality technicians — no installation in the traditional sense is required. Before use, clean the gage and the bore being inspected to remove chips, coolant, and debris that could affect the reading. Apply light gage oil when storing to prevent corrosion on the steel surfaces. Never force a plug gage into an undersized hole, as this will damage the gage and compromise its accuracy.