Spi 29-688-9 Class Zz Plus Plug Gage 0.688 Inch

Product Description

The SPI 29-688-9 is a Class ZZ Plus plug gage designed to verify the diameter of machined holes to a nominal size of 0.688 inches with a tolerance of 0.0002 inches. Plug gages of this class are used in quality control and inspection environments where precise go/no-go diameter verification is required. Manufactured from steel, this gage provides the dimensional stability and wear resistance expected in production and toolroom inspection work. It is handled by machinists, quality technicians, and tool and die professionals as part of standard dimensional inspection procedures.

This plug gage is suited for use in machine shops, toolrooms, and manufacturing facilities where hole diameter verification is part of the inspection process. The 0.688 inch nominal diameter makes it applicable to medium-range bore inspection tasks in both high-volume production and low-volume precision work. It is a single-unit item, appropriate for bench inspection stations or portable use at the machine.

Key Features

• Class ZZ Plus tolerance rating for reliable go/no-go hole inspection
• Nominal measurement diameter of 0.688 inches
• Tolerance of 0.0002 inches for tight dimensional verification
• Steel construction for durability and dimensional stability
• Lightweight at 0.2 pounds, suitable for bench or portable inspection use

Compatibility

Designed as an OEM-style replacement or direct-use plug gage for standard Class ZZ Plus inspection applications requiring a 0.688 inch nominal bore diameter verification.

Installation Notes

Plug gages are handled by qualified inspection or machining personnel and do not require installation in the traditional sense. Before use, clean both the gage and the bore to be measured to prevent false readings from debris or coolant residue. Store the gage in a protective case when not in use to prevent surface damage that could affect accuracy. Calibration and handling should follow applicable ASME or ANSI dimensional metrology standards.