Spi 29-860-4 Class Zz Plus Plug Gage 0.86 Inch

Product Description

The SPI 29-860-4 is a Class ZZ Plus plug gage used to inspect and verify the diameter of machined holes and bores with a nominal measurement of 0.86 inches. Manufactured from steel, it delivers a tolerance of 0.0002 inches, placing it within the Class ZZ Plus accuracy standard used for general-purpose go/no-go inspection work. Machinists, toolroom technicians, and quality control personnel use plug gages like this to confirm that drilled, reamed, or bored holes fall within acceptable tolerance limits before parts proceed through production or assembly.

This gage is suited for inspection applications in machine shops, toolrooms, and manufacturing environments where hole diameter verification is required. It is a single-size gage intended for use at a nominal bore diameter of 0.86 inches. It fits into standard gage holding handles and is compatible with conventional plug gage inspection procedures used in both production floor and bench inspection settings.

Key Features

• Nominal measurement diameter of 0.86 inches for precise hole inspection
• Class ZZ Plus tolerance of 0.0002 inches for general-purpose go/no-go gauging
• Steel construction for durability and dimensional stability in shop environments
• Lightweight at 0.2 pounds for easy single-hand use during inspection
• Compatible with standard plug gage handles used in toolroom and production inspection

Compatibility

Designed as an OEM-style replacement or direct-use Class ZZ Plus plug gage for standard bore inspection applications requiring a 0.86-inch nominal diameter measurement.

Installation Notes

Plug gages are installed and removed by hand into the bore being inspected. No power tools or heat sources are required. Keep the gage clean and lightly oiled when stored to prevent corrosion and maintain dimensional accuracy. Gages should be periodically recalibrated or checked against a certified master to ensure measurements remain traceable to ANSI or ASME B89 standards.