Spi 29-178-1 Class Zz Plus Plug Gage 0.178 in Dia

Product Description

The SPI 29-178-1 is a Class ZZ Plus plug gage designed for inspecting hole diameters in precision machining and quality control applications. It measures a nominal diameter of 0.178 inches with a tolerance of 0.0002 inches, making it suitable for go/no-go inspection of tight-tolerance bored or drilled holes. Constructed from steel, this gage provides the durability and dimensional stability required for repeated use on the shop floor or in an inspection environment. Metrology technicians, machinists, and quality control inspectors use this type of instrument to verify that finished holes meet print specifications before parts advance through production.

This plug gage is used in manufacturing, machining, and inspection environments where hole-diameter verification is part of the quality process. It is appropriate for checking small-diameter holes in metal components, tooling, and precision assemblies. The Class ZZ Plus designation indicates a commercial-grade tolerance class suited for production inspection rather than master or working gage applications. A single gage is packaged per unit, making it straightforward to add individual sizes to an existing gage set as needed.

Key Features

• 0.178-inch nominal measurement diameter for small-hole inspection
• Class ZZ Plus tolerance class rated at 0.0002 inches for reliable go/no-go verification
• Steel construction provides dimensional stability and wear resistance
• Single-piece packaging allows individual size procurement without buying a full set
• Compact and lightweight at 0.2 pounds for easy bench or in-process use

Compatibility

Designed as an OEM-style replacement or direct addition to Class ZZ plug gage sets used for small-diameter hole inspection in precision machining and quality control workflows.

Installation Notes

Plug gages are handled and used by metrology technicians or machinists performing dimensional inspection. Before use, clean both the gage and the workpiece bore with a lint-free cloth to remove chips, coolant, or debris that could affect the reading. Never force a plug gage into a hole; apply light, steady hand pressure only to avoid scoring the gage or distorting the bore. Store the gage in its protective case away from other tooling to prevent surface damage and maintain calibration integrity.