Spi 29-306-8 Class Zz Plus Plug Gage 0.306 in Dia

Product Description

The SPI 29-306-8 is a Class ZZ Plus plug gage designed to verify bore and hole diameters to a nominal size of 0.306 inches. Built from steel, this go/no-go style gage delivers a tolerance of 0.0002 inches, making it suitable for precision inspection work in machine shops, toolrooms, and manufacturing environments. Machinists, quality control technicians, and tool-and-die professionals use plug gages like this one to confirm that drilled, reamed, or bored holes meet tight dimensional specifications before parts move to the next stage of production.

This gage is applicable in any setting where hole diameter verification is required to close tolerances. Typical use cases include incoming inspection, in-process quality checks, and final part acceptance. The 0.306-inch nominal diameter covers a common bore size found in general machining, fixture fabrication, and precision assembly operations. Its compact size and light weight make it easy to handle at the bench or on the shop floor.

Key Features

• Class ZZ Plus tolerance classification for precision hole inspection
• 0.306-inch nominal measurement diameter
• 0.0002-inch tolerance for tight dimensional control
• Steel construction for durability and wear resistance
• Compact and lightweight at 0.2 pounds for easy handling

Compatibility

Designed as a standard Class ZZ Plus plug gage for verifying 0.306-inch nominal diameter holes in general precision machining and inspection applications.

Installation Notes

Plug gages are used by qualified machinists and quality control technicians and require no installation. Clean the gage and the bore thoroughly before use to prevent debris from affecting measurement accuracy. Store the gage in its case when not in use to protect the precision ground surface from damage. Never force the gage into a bore, as this can damage both the gage and the workpiece.