Spi 29-378-7 Class Zz Plus Plug Gage 0.378 in

Product Description

The SPI 29-378-7 is a Class ZZ Plus plug gage designed for precision go/no-go inspection of machined bores and holes with a nominal diameter of 0.378 inches. Built to Class ZZ Plus tolerances of 0.0002 inches, this gage gives quality control technicians and machinists a reliable, low-cost tool for verifying hole size acceptance in production and inspection environments. The steel construction provides durability for repeated use in shop-floor conditions. It is used wherever tight dimensional verification is required on drilled, reamed, or bored features.

This plug gage is suited for use in manufacturing, fabrication, and machine shop settings where hole diameter must be verified against a controlled tolerance. It fits standard inspection routines for small-diameter bores and is appropriate for incoming inspection, in-process checks, and final quality audits. Machinists, QC inspectors, and tool and die professionals are the typical end users. The 0.378-inch nominal diameter makes it applicable to a specific range of drilled or reamed hole sizes produced to close tolerances.

Key Features

• Class ZZ Plus tolerance rating of 0.0002 inches for precise go/no-go inspection
• Nominal measurement diameter of 0.378 inches
• Steel construction for shop-floor durability and wear resistance
• Compact and lightweight at 0.2 pounds for easy handling
• Single-piece packaging — ready to use out of the box

Compatibility

Designed as an OEM-style Class ZZ Plus plug gage for go/no-go hole inspection of 0.378-inch nominal diameter bores in standard manufacturing and quality control applications.

Installation Notes

Plug gages are used by QC inspectors and machinists and require no installation tools, but proper gage handling practices apply. Clean the bore and gage surfaces before use to prevent debris from affecting readings or causing premature gage wear. Never force a plug gage through a hole — if the gage does not pass freely, the bore is undersized. Store the gage in its protective sleeve or case when not in use to protect the precision-ground surface.