Spi 29-290-4 Class Zz Plus Plug Gage 0.29 in Dia

Product Description

The SPI 29-290-4 is a Class ZZ Plus plug gage used to verify the dimensional accuracy of drilled, reamed, or bored holes. It checks whether a hole meets its specified diameter tolerance by using a hardened steel go or no-go member that either passes or does not pass through the work. The 29-290-4 measures a nominal diameter of 0.29 inches with a tolerance of 0.0002 inches, making it suitable for close-tolerance inspection work. Machinists, tool and die makers, and quality control technicians typically use this type of gage during in-process and final inspection on precision components.

This plug gage is intended for use in machine shops, manufacturing facilities, and inspection departments where hole size must be confirmed to a tight standard. It is applied wherever a 0.29-inch nominal hole diameter must be verified against print tolerance. Class ZZ Plus gages are generally used for production inspection of commercial-grade work where moderate precision is required. The steel construction provides durability through repeated use on metal, plastic, and composite workpieces.

Key Features

• Class ZZ Plus tolerance grade for production-level hole inspection
• 0.29-inch nominal measurement diameter
• 0.0002-inch tolerance for close-tolerance verification
• Steel construction for wear resistance and dimensional stability
• Compact, single-piece format suitable for bench or floor inspection use

Compatibility

Designed as a standard Class ZZ Plus plug gage for verifying 0.29-inch nominal diameter holes in general production inspection applications.

Installation Notes

Plug gages require no installation but should be handled and stored carefully to prevent damage to the gaging surface. Clean the gage and the workpiece bore before use to remove chips, coolant, or debris that could affect the measurement. Do not force the gage member through a hole; if resistance is encountered, the hole is undersize. Periodic calibration against a traceable standard is recommended to confirm gage accuracy over time.