Spi 29-166-6 Class Zz Plus Plug Gage 0.166 Inch

Product Description

The SPI 29-166-6 is a Class ZZ Plus plug gage designed for go/no-go inspection of drilled, reamed, or bored holes with a nominal diameter of 0.166 inches. Class ZZ is the standard tolerance grade for production-floor inspection work, and the Plus designation indicates the gage is sized at the high end of tolerance to maximize usable wear life. With a dimensional tolerance of 0.0002 inches, it provides reliable verification of hole size without the tighter tolerances required for Class Z or Class ZX master gages. The steel construction gives it the hardness and stability expected from a working-grade plug gage. Machinists, quality technicians, and tool room personnel typically keep these in regular rotation on high-volume inspection lines.

This plug gage is suited for general production inspection in machine shops, fabrication facilities, and manufacturing environments where consistent hole diameter verification is required. It is commonly used to check close-tolerance through-holes in metal parts after drilling, reaming, or boring operations. The 0.166 inch diameter is a common fractional and decimal-inch size encountered in standard fastener clearance and pin-fit applications across a wide range of industries including aerospace, automotive, and general metalworking.

Key Features

• Class ZZ Plus tolerance grade for production-floor go/no-go hole inspection
• 0.166 inch nominal measurement diameter
• 0.0002 inch dimensional tolerance for consistent, repeatable results
• Steel construction for durability and wear resistance in regular use
• Compact and lightweight at 0.2 pounds for easy single-hand handling

Compatibility

Designed as an OEM-style working gage for production inspection of 0.166 inch nominal diameter holes in metal components. Suitable for use wherever Class ZZ plug gage standards apply.

Installation Notes

Plug gages are handled by quality technicians and machinists and require no permanent installation. Keep the gage clean and lightly oiled when not in use to prevent corrosion and protect the ground surface. Do not force the gage through an undersized hole, as this will damage the precision-ground diameter and invalidate the measurement. Periodically verify the gage against a calibrated master to confirm it has not worn beyond its tolerance band.