Spi 29-031-2 Class Zz Plus Plug Gage 0.031 in

Product Description

The SPI 29-031-2 is a Class ZZ Plus plug gage machined to a nominal diameter of 0.031 inches with a tolerance of 0.0002 inches. Plug gages are used to verify that a drilled, reamed, or bored hole falls within a specified dimensional range. This gage is made from steel for durability and dimensional stability under shop conditions. It belongs to the ZZ tolerance class, which is the standard working gage grade used in general inspection and production environments. Machinists, quality technicians, and tool-and-die professionals use this type of gage to confirm hole acceptance without the need for more complex measuring instruments.

The 29-031-2 is suited for inspecting small-diameter holes in production machining, precision fabrication, and quality control applications. At 0.031 inches nominal diameter, it is appropriate for fine-bore inspection tasks where tight dimensional control is required. It is a go or no-go style inspection tool that fits into standard plug gage handle systems used in machine shops and inspection departments across manufacturing and metalworking trades.

Key Features

• Nominal diameter of 0.031 inches for small-bore inspection
• Class ZZ Plus tolerance of 0.0002 inches for reliable working-gage accuracy
• Steel construction for wear resistance and dimensional stability
• Compatible with standard plug gage handle systems
• Single-piece unit sold individually

Compatibility

Designed as an OEM-style working gage for use with standard plug gage handles compatible with 0.031-inch diameter gage blanks in general inspection and production machining applications.

Installation Notes

Plug gages are handled and used by quality technicians and machinists in accordance with standard metrology practices. Before use, clean the gage and the hole being inspected to remove chips, coolant, and debris that could affect the measurement. Do not force the gage into a hole; forcing can damage the gage or the workpiece and will produce invalid results. Store the gage in a protective case away from other metal tools to prevent nicks and wear that would compromise its calibrated tolerance.