Spi 22-172-1 Class Zz Plug Gage Set 0.251-0.5 in 250 Pc

Product Description

The SPI 22-172-1 is a 250-piece Class ZZ plug gage set covering a diameter range of 0.251 inches to 0.500 inches. Designed for shop-floor and inspection use, the set allows technicians to verify hole sizes, slot widths, and center distances quickly and accurately. Each pin gage is manufactured from steel and held to a plus tolerance of 0.0002 inches, meeting Class ZZ standards for go-gage inspection work. A certificate of accuracy with NIST-traceable calibration is included, along with a pin gage holder for organized storage and retrieval. The complete set weighs 21.94 pounds.

This set is suited for quality control and dimensional inspection in machining, fabrication, and manufacturing environments. It covers the 0.251-inch to 0.500-inch range in fine increments, making it practical for inspecting drilled, reamed, and punched holes across a wide variety of workpiece materials. Applications include go-gage inspection of hole tolerances, slot width verification, and calculating distances between hole centerlines. The set is appropriate for use by machinists, quality technicians, tool-and-die makers, and maintenance professionals who need reliable, traceable measurement tools at the bench or on the floor.

Key Features

• 250-piece set covers 0.251 inches to 0.500 inches diameter range
• Class ZZ tolerance of plus 0.0002 inches per pin
• Steel construction for durability and dimensional stability
• NIST-traceable certificate of accuracy included with each set
• Pin gage holder included for organized access during inspection
• Suitable for go-gage inspection, hole sizing, slot width, and inter-hole distance measurements

Compatibility

Designed as a standard Class ZZ plug gage set for use in dimensional inspection applications requiring hole and slot measurements in the 0.251-inch to 0.500-inch range.

Installation Notes

Plug gages should be handled and stored carefully to prevent nicking or corrosion, which can affect dimensional accuracy. Clean gages and the workpiece hole before use to avoid false readings caused by debris or machining chips. Do not force a pin gage into an undersize hole, as this can damage both the gage and the workpiece. Recalibrate or replace individual pins if the certificate of accuracy becomes outdated per your facility quality management requirements.