Spi 29-442-1 Class Zz Plus Plug Gage 0.442 in

Product Description

The SPI 29-442-1 is a Class ZZ Plus plug gage used to verify the inside diameter of bored, drilled, or reamed holes to a nominal size of 0.442 inches. Built from steel, this gage delivers a tolerance of 0.0002 inches, making it a reliable go-to tool for dimensional inspection on the shop floor or in a quality-control environment. Machinists, toolmakers, and QC inspectors use plug gages like this one to confirm whether a finished hole meets print specifications without the need for a measuring instrument readout.

Class ZZ Plus plug gages are typically used in production inspection settings where moderate accuracy is required. This gage is suited for checking holes in metal or plastic workpieces where the nominal diameter is 0.442 inches. It is a single-end gage intended for pass or fail verification. Typical applications include incoming inspection, in-process checks on CNC or manual machining operations, and final inspection before part acceptance.

Key Features

• Nominal measurement diameter of 0.442 inches for precise hole verification
• Class ZZ Plus tolerance of 0.0002 inches for consistent pass/fail inspection
• Steel construction for durability in production and inspection environments
• Compact and lightweight at 0.2 pounds for easy single-hand use
• Single-unit packaging suitable for individual bench or field use

Compatibility

Designed as an OEM-style inspection tool for use wherever a 0.442-inch nominal diameter plug gage is specified by print or quality plan.

Installation Notes

Plug gages should be handled with clean, dry hands or lint-free gloves to prevent corrosion from skin oils. Before use, verify the gage is clean and free of burrs or debris that could affect the reading. Do not force the gage into a hole; if it does not enter under light hand pressure, the hole is undersize. Store the gage in its case or a protected location to maintain calibration integrity.