Spi 19-125-4 Class Zz Minus Plug Pin Gage 0.125 in

Product Description

The SPI 19-125-4 is a Class ZZ minus plug pin gage machined from steel and used to verify bore and hole dimensions in precision measurement applications. With a nominal diameter of 0.125 inches and a minus tolerance of 0.0002 inches, this gage provides a reliable go/no-go reference for quality control checks in machine shops, manufacturing facilities, and maintenance environments. The minus designation means the gage is ground to the low end of the tolerance band, making it suitable for checking minimum acceptable hole size. Machinists, toolmakers, and quality technicians use plug pin gages as a fast, repeatable method for dimensional verification without requiring calipers or micrometers at every check point.

This gage is well-suited for inspecting drilled, reamed, or bored holes where tight dimensional control is required. It fits into standard gage handle holders and can be used as a standalone pin for quick pass-fail inspection on production lines or in toolroom settings. The 0.125 inch diameter makes it appropriate for small-bore applications commonly found in precision machined components, hydraulic fittings, and similar parts requiring close hole tolerances.

Key Features

• Class ZZ tolerance grade provides an economical standard for general-purpose go/no-go inspection
• Minus plug designation ground to the low side of the tolerance band for minimum hole size verification
• 0.0002 inch tolerance ensures consistent and repeatable dimensional checking
• Steel construction offers durability for repeated use in shop and inspection environments
• 0.125 inch nominal diameter covers small-bore hole inspection requirements
• Compatible with standard plug gage handles for ergonomic use

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use with conventional gage handle holders in general-purpose dimensional inspection of 0.125 inch nominal diameter bores.

Installation Notes

Plug pin gages are handled and used by machinists, toolmakers, and quality control technicians. Before use, clean the gage and the hole being checked to remove chips, coolant, and debris that could affect the reading. Insert the gage with light, steady hand pressure only — never force a plug gage into a bore, as this can damage both the gage and the workpiece. Store pin gages in a protective case away from other tooling to prevent nicks and wear that would compromise accuracy.