Spi 29-346-4 Class Zz Plus Plug Gage 0.346 in

Product Description

The SPI 29-346-4 is a Class ZZ Plus plug gage designed to verify that a drilled, reamed, or bored hole meets a specified nominal diameter of 0.346 inches. Manufactured from steel, it delivers a tolerance of 0.0002 inches, making it suitable for go/no-go inspection work in production and shop environments. Class ZZ Plus gages conform to established American Gage Design standards for cylindrical plug gages and are a standard tool for machinists, tool-and-die makers, and quality control technicians who need fast, repeatable bore verification without the setup time required by a dial bore gage.

This plug gage is used in metalworking, machining, and manufacturing inspection applications where hole diameter conformance must be confirmed to close tolerance. It is appropriate for both incoming inspection and in-process quality checks on parts produced by drilling, reaming, boring, or honing. The 0.346-inch nominal size covers a common fractional and close-decimal bore range found in general machining work. Its compact, lightweight form allows easy use at the machine or on an inspection bench.

Key Features

• Nominal measurement diameter of 0.346 inches for precise bore inspection
• Class ZZ Plus tolerance of 0.0002 inches meets standard go/no-go gage accuracy requirements
• Steel construction provides durability and wear resistance in shop environments
• Lightweight at 0.2 pounds for easy single-hand use
• Single-piece packaging suits individual replacement or kit supplementation

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any application requiring go/no-go inspection of a 0.346-inch nominal bore to Class ZZ Plus standards.

Installation Notes

Plug gages are used by quality control technicians and machinists and require no installation in the mechanical sense, but proper handling is essential for accurate results. Clean the bore and gage surfaces before use to prevent debris from causing false rejections or premature wear. Never force a plug gage into a hole; if resistance is felt, the bore is undersize and should be returned for rework. Store the gage in its protective case or on a gage block when not in use to prevent surface damage that would affect measurement accuracy.