Spi 29-856-2 Class Zz Plus Plug Gage 0.856 in

Product Description

The SPI 29-856-2 is a Class ZZ Plus plug gage designed for precision hole diameter inspection. It measures a nominal bore diameter of 0.856 inches with a tolerance of 0.0002 inches, making it suitable for go/no-go acceptance inspection of machined holes. The gage body is constructed from steel for durability and dimensional stability under repeated use. Machinists, quality control technicians, and tool room professionals use this type of gage to verify that drilled or reamed holes fall within specified tolerance limits before parts advance to the next stage of production.

Class ZZ Plus plug gages are typically used in production and inspection environments where hole diameters must be verified to close tolerances. This gage is appropriate for checking bores in metal components across general machining, manufacturing, and fabrication applications. Its compact size and straightforward design make it well suited for both bench inspection and floor-level quality checks on machined parts and assemblies.

Key Features

• Nominal measurement diameter of 0.856 inches for direct hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for high-accuracy go/no-go gauging
• Steel construction provides wear resistance and long service life
• Designed for production inspection and quality control environments
• Compact form factor suitable for bench or floor use

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any application requiring Class ZZ Plus inspection of 0.856-inch nominal bore diameters in machined metal components.

Installation Notes

Plug gages should be handled and stored carefully to prevent damage to the precision ground surfaces. Before use, clean the gage and the bore being inspected to remove debris, oil, and chips that could affect measurement accuracy. Do not force the gage through a hole; apply only light, consistent hand pressure during inspection. Gages should be periodically calibrated and checked for wear according to your facility quality standards and applicable metrology guidelines.