Spi 29-558-4 Class Zz Plus Plug Gage 0.558 Inch

Product Description

The SPI 29-558-4 is a Class ZZ Plus plug gage designed to verify the inside diameter of bored or reamed holes with a nominal size of 0.558 inches. It holds a tolerance of 0.0002 inches, making it suitable for go/no-go inspection in production environments where consistent hole sizing is critical. Constructed from steel, this gage provides the hardness and wear resistance needed for repeat use on the shop floor. Machinists, toolmakers, and quality control technicians use Class ZZ plug gages as a fast, reliable method for dimensional verification without the need for electronic measurement equipment.

This gage is used in metalworking, machining, and precision manufacturing settings where hole diameter acceptance must be confirmed before assembly or further processing. It is well suited for inspecting drilled, reamed, or bored holes in steel, aluminum, and other common workpiece materials. The 0.558 inch nominal diameter fits a specific range of hole sizes where direct-contact gaging delivers faster throughput than CMM or air gaging in a high-volume inspection workflow.

Key Features

• 0.558 inch nominal diameter for direct hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for reliable go/no-go results
• Steel construction for durability and wear resistance in production use
• Compact, lightweight design at 0.2 pounds for easy bench or floor use
• Single-piece package quantity — no minimum order beyond one unit

Compatibility

Designed as a standard Class ZZ Plus plug gage for use with any workpiece or fixture requiring verification of a 0.558 inch inside diameter hole to accepted go/no-go inspection standards.

Installation Notes

Plug gages are handled and applied by machinists or quality inspectors — no power source or lockout procedure is required. Ensure the workpiece is clean and free of burrs or chips before gaging to avoid false readings or gage wear. Handle the gage with clean, dry hands or inspection gloves to prevent corrosion from skin contact. Store in a protective case away from other tooling to preserve the gaging surface and tolerance integrity.