Spi 29-056-9 Class Zz Plus Plug Gage 0.056 in

Product Description

The SPI 29-056-9 is a Class ZZ Plus plug gage used to inspect and verify hole diameters to a precise 0.056-inch nominal dimension. It holds a tolerance of 0.0002 inches, placing it in the tighter ZZ Plus classification suitable for quality-control work in production and inspection environments. The gage is constructed from steel for durability and dimensional stability under repeated use. Machinists, toolroom technicians, and quality inspectors use plug gages as go/no-go reference tools to confirm bore conformance during part manufacturing and incoming inspection.

This gage is suited for applications requiring fine-diameter verification at 0.056 inches, including small-bore machined components, drilled holes in metal or plastic assemblies, and precision inspection tasks where tight dimensional control is required. It is appropriate for both production-floor spot checks and bench-level inspection setups. The compact size and steel construction make it durable for regular handling in manufacturing and metrology environments.

Key Features

• 0.056-inch nominal diameter for small-bore inspection
• Class ZZ Plus tolerance of 0.0002 inches for precise go/no-go verification
• Steel construction for dimensional stability and wear resistance
• Compact, single-piece gage format suited to bench and production use

Compatibility

Designed as an OEM-style plug gage for use in standard go/no-go gage handle sets or as a standalone inspection tool for small-diameter bore verification in general machining and quality-control applications.

Installation Notes

Plug gages are handled by quality inspectors and toolroom technicians; no power-down procedures apply. Clean the gage and the bore being inspected before use to prevent measurement errors from debris or oil film. Store in a protective case away from heat sources to maintain dimensional accuracy. Do not force the gage into an undersized bore, as this can damage the gage surface and alter its calibration.