Spi 19-538-8 Class Zz Minus Plug Pin Gage 0.538 in

Product Description

The SPI 19-538-8 is a Class ZZ minus plug pin gage machined from steel, designed to verify that a hole or bore meets its minimum acceptable size. The gage measures 0.538 inches in diameter with a minus tolerance of 0.000200 inches, confirming that a feature is at or above the lower limit of its tolerance band. Class ZZ gages are the standard working-grade instrument for production inspection and quality control. Machinists, toolmakers, and quality technicians use plug gages like this one to perform go/no-go dimensional checks on drilled, reamed, or bored holes without requiring a CMM or air gage setup.

This pin gage is suited for use in machine shops, manufacturing cells, and inspection departments where hole diameter verification is a routine task. It is appropriate for both ferrous and non-ferrous workpieces where a 0.538-inch nominal bore diameter must be confirmed. The minus designation means the gage is ground below the nominal diameter by the stated tolerance, functioning as a go-type check for minimum hole size acceptance. It applies wherever tight dimensional control is required on production or repair work.

Key Features

• Class ZZ working-grade tolerance for standard production inspection
• Minus tolerance ground to 0.000200 inches below nominal diameter
• 0.538-inch nominal diameter for direct bore verification
• Steel construction for durability in shop environments
• Single-piece pin format for straightforward handheld use

Compatibility

Designed as a standard Class ZZ minus plug pin gage for use with any gage handle or pin gage set holder accepting 0.538-inch diameter pin members, consistent with common working-grade inspection tooling.

Installation Notes

Plug pin gages are used by quality technicians and machinists and require no installation in the conventional sense. Before use, clean both the gage and the workpiece bore to remove chips, coolant, and debris that could cause a false reading or damage the gage surface. Insert the pin into the bore with light, controlled hand pressure only — never force a plug gage, as this can score the gage or distort the bore. Store the gage in its case or protective sleeve and apply a light coat of rust-preventive oil when not in use to maintain accuracy over time.