Spi 29-639-2 Class Zz Plus Plug Gage 0.639 Inch

Product Description

The SPI 29-639-2 is a Class ZZ Plus plug gage designed for inspecting 0.639-inch diameter bores and holes to a tolerance of 0.0002 inches. This go/no-go style precision instrument is used to verify that machined features fall within acceptable dimensional limits without requiring a CMM or digital measuring system. Constructed from steel for durability and dimensional stability, this plug gage is a standard shop-floor tool used by machinists, quality technicians, and tool room personnel performing incoming, in-process, or final inspection work.

This gage is suited for use in machine shops, manufacturing facilities, and quality labs where consistent hole diameter verification is required. Its compact, lightweight form makes it practical for use at the machine or on an inspection bench. The 0.0002-inch tolerance class makes it appropriate for moderate-precision applications where part conformance to a 0.639-inch hole specification must be confirmed efficiently and repeatedly.

Key Features

• 0.639-inch nominal diameter for direct bore inspection at that specification
• Class ZZ Plus tolerance rating at 0.0002 inches for reliable go/no-go decisions
• Steel construction for wear resistance and dimensional stability under shop conditions
• Single-unit packaging suitable for individual gage replacement or addition to inspection sets
• Lightweight at 0.2 pounds for easy one-handed use during inspection

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for inspection applications requiring a 0.639-inch Class ZZ Plus go/no-go standard in steel.

Installation Notes

Plug gages are handled and used by quality technicians and machinists and do not require power or mechanical installation. Store the gage in a protective case away from abrasive surfaces and temperature extremes to maintain calibration integrity. Before use, clean the gage and bore with a lint-free cloth to prevent debris from affecting the measurement result. Periodic recalibration against a certified master is recommended to ensure ongoing accuracy per your facility quality plan.