Spi 19-178-3 Class Zz Minus Plug Pin Gage 0.178 in

Product Description

The SPI 19-178-3 is a Class ZZ minus plug pin gage designed to verify hole diameters in precision machining and inspection work. It measures 0.178 inches in diameter and holds a tolerance of 0.0002 inches, making it suitable for go/no-go gauging applications where dimensional accuracy is critical. Manufactured from steel, this pin gage is a standard tool in quality control environments, toolrooms, and production floor inspection stations. Machinists, toolmakers, and quality technicians use pin gages like this one to confirm bore and hole sizes conform to engineering tolerances without relying on calipers or micrometers alone.

The 19-178-3 is suited for inspection of drilled, reamed, or punched holes in metal, plastic, and composite workpieces. It fits into standard pin gage set handles or can be used as a standalone check pin depending on the application. Typical use cases include incoming inspection, in-process quality checks, and final verification on machined components. This is a minus-type gage, meaning it is manufactured to the lower end of the tolerance band, which is standard practice for plug gages used in go-gage applications.

Key Features

• Class ZZ tolerance rating provides an economical option for general-purpose inspection work
• Minus designation indicates the gage is ground to the lower tolerance limit, consistent with go-gage convention
• 0.0002 inch tolerance ensures reliable dimensional verification at the 0.178 inch diameter
• Steel construction offers durability and resistance to wear under repeated use
• Lightweight at 0.2 pounds, making it easy to handle during repeated inspections

Compatibility

Designed as an OEM-style individual pin gage compatible with standard plug gage handles and holders used in general machining and inspection applications.

Installation Notes

Pin gages should be handled with clean, dry hands or cotton gloves to prevent corrosion from skin oils. Before use, verify the gage and the workpiece bore are at the same ambient temperature to avoid thermal expansion errors. Store the gage in its case or a lightly oiled protective environment when not in use. Inspection personnel should follow applicable ASME B89 dimensional measurement standards when using plug pin gages in quality control procedures.