Spi 29-850-5 Class Zz Plus Plug Gage 0.85 Inch

Product Description

The SPI 29-850-5 is a Class ZZ Plus plug gage designed for precision bore and hole measurement in machining, manufacturing, and inspection environments. Built from steel, this go/no-go style gage checks whether a hole falls within the required dimensional tolerance. The 29-850-5 measures holes with a nominal diameter of 0.85 inches and holds a tolerance of 0.0002 inches, making it appropriate for moderate-precision inspection work. Machinists, quality control technicians, and toolroom professionals use plug gages like this one to verify drilled, reamed, or bored features against print specifications quickly and without complex setup.

This gage is suited for use in job shops, production machining facilities, and inspection departments where consistent, repeatable hole verification is required. Class ZZ Plus designation indicates a commercial-grade tolerance class appropriate for general inspection of workpiece features rather than master gage or laboratory applications. The steel construction provides durability for regular shop-floor use across ferrous and non-ferrous workpiece materials.

Key Features

• Nominal measurement diameter of 0.85 inches for direct bore inspection
• Tolerance of 0.0002 inches supporting moderate-precision dimensional verification
• Class ZZ Plus rating for commercial-grade go/no-go inspection work
• Steel construction for shop-floor durability and resistance to wear
• Single-piece package quantity for individual replacement or kit supplementing

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for any inspection application requiring a 0.85-inch nominal diameter Class ZZ Plus go/no-go gage in steel.

Installation Notes

Plug gages should be handled and stored with care to prevent surface damage that would affect measurement accuracy. Clean the gage and the workpiece bore before use to remove chips, coolant, or debris that can affect readings. Do not force the gage into a bore; improper insertion can damage both the gage and the workpiece. Calibration verification against a certified master is recommended on a scheduled basis per applicable quality system requirements.