Spi 29-021-3 Class Zz Plus Plug Gage 0.021 in

Product Description

The SPI 29-021-3 is a Class ZZ Plus plug gage used to verify bore and hole diameters in precision machining and inspection work. It measures a nominal diameter of 0.021 inches with a tolerance of 0.0002 inches, making it suited for close-tolerance quality control tasks. Constructed from steel, this gage is built to withstand repeated use in shop-floor inspection environments. Machinists, tool and die makers, and quality control technicians use this type of gage to confirm whether a drilled or reamed hole falls within specified limits.

This gage is appropriate for use in manufacturing, tooling, and precision inspection applications where small-diameter holes must be confirmed to tight tolerances. It is typically deployed in production settings requiring go/no-go verification at the 0.021-inch diameter range. The compact size makes it practical for bench inspection and in-process checks on machined components.

Key Features

• Nominal measurement diameter of 0.021 inches for small-bore inspection
• Class ZZ Plus tolerance rating of 0.0002 inches for close-tolerance verification
• Steel construction for durability and dimensional stability
• Single-piece package quantity suitable for individual use or replacement
• Compact form factor for bench and in-process inspection tasks

Compatibility

Designed as a Class ZZ Plus plug gage for verifying 0.021-inch nominal diameter bores in standard precision machining and inspection applications.

Installation Notes

Handle plug gages with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Store the gage in its protective case when not in use to avoid damage to the precision-ground surface. Calibration and use should follow applicable metrology standards; gages should be inspected periodically for wear that could affect accuracy. Do not force the gage into a hole, as this can damage both the gage and the workpiece.