Spi 29-381-1 Class Zz Plus Plug Gage 0.381 in Dia

Product Description

The SPI 29-381-1 is a Class ZZ Plus plug gage used to verify hole diameters to a tight dimensional tolerance of 0.0002 inches. Built from steel, this go/no-go style gage gives machinists, toolmakers, and quality-control technicians a reliable, direct method for checking bore size conformance on production and inspection work. At 0.381 inches in diameter, it fits applications requiring precise small-bore verification. Class ZZ Plus designates a tolerance grade suitable for general-purpose inspection of manufactured parts where consistent dimensional control is required.

This plug gage is suited for use in machine shops, manufacturing facilities, and inspection departments where hole diameter verification is part of standard quality assurance workflow. It applies to ferrous and non-ferrous workpieces where a 0.381-inch nominal bore must be confirmed within tolerance. Typical users include machinists, metrology technicians, and QC inspectors working with close-tolerance turned, drilled, or reamed holes.

Key Features

• 0.381-inch nominal measurement diameter for small-bore inspection
• Class ZZ Plus tolerance grade at 0.0002 inches for reliable dimensional verification
• Steel construction for durability and wear resistance in shop environments
• Compact and lightweight at 0.2 pounds for easy handheld use
• Single-piece package quantity — no minimum multi-pack requirement

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for inspection of 0.381-inch nominal diameter bores in standard machining and quality-control applications.

Installation Notes

Plug gages are used by metrology and machining personnel and require no permanent installation. Clean the gage and bore before use to prevent debris from affecting measurement accuracy. Do not force the gage into the bore; excessive insertion force can damage the gage land or the workpiece surface. Store the gage in a protective case away from other tooling to prevent contact damage to the precision-ground surface.