Spi 29-554-3 Class Zz Plus Plug Gage 0.554 in

Product Description

The SPI 29-554-3 is a Class ZZ Plus plug gage designed to check the inside diameter of machined holes to a nominal size of 0.554 inches. Built from steel, this go/no-go style gage gives machinists and quality inspectors a fast, reliable method for verifying bore tolerances during in-process or final inspection. The Class ZZ Plus designation indicates a tolerance of 0.0002 inches, making it suitable for checking holes held to standard commercial tolerances. The gage weighs approximately 0.2 pounds and is intended for bench or floor use in production and inspection environments.

This plug gage is used in machine shops, manufacturing facilities, and quality control departments where consistent hole-size verification is required. It is appropriate for both production-floor spot checks and more formal inspection station use. Typical applications include verifying bored, reamed, or drilled holes in metal components where dimensional conformance to print is required. Installation and use do not require power or calibration equipment beyond routine gage block verification.

Key Features

• Nominal measurement diameter of 0.554 inches for direct hole-size verification
• Class ZZ Plus tolerance of 0.0002 inches for standard commercial inspection work
• Steel construction for durability and wear resistance in production environments
• Lightweight at 0.2 pounds for easy single-hand operation
• Single-piece packaging with a minimum order quantity of 1

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any application requiring inspection of a 0.554-inch nominal bore diameter to Class ZZ Plus standards.

Installation Notes

Plug gages are used by machinists and quality control inspectors and require no power source or installation in the traditional sense. Before use, clean the gage and the bore being checked to remove chips, coolant, and debris that could cause false readings. Handle the gage carefully to avoid dropping, as impact can alter the ground surface and invalidate the tolerance. Periodic calibration against certified gage blocks is recommended to maintain measurement integrity.