Spi 29-321-7 Class Zz Plus Plug Gage 0.321 in

Product Description

The SPI 29-321-7 is a Class ZZ Plus plug gage designed to verify bore and hole diameters to a nominal size of 0.321 inches with a tolerance of 0.0002 inches. Machined from steel, this fixed-limit gage provides a reliable go/no-go reference for quality control inspection in machine shops, manufacturing facilities, and production environments. Machinists, quality technicians, and toolroom professionals use plug gages like this one to confirm that drilled, reamed, or bored holes meet specification before parts advance to the next stage of production.

The 29-321-7 is suited for inspection applications requiring precise diameter verification at the 0.321-inch nominal size. Class ZZ tolerance class is appropriate for general-purpose inspection and incoming quality checks. The gage is packaged individually and is ready for immediate use on the shop floor or inspection bench.

Key Features

• Nominal diameter of 0.321 inches for direct bore verification
• Class ZZ Plus tolerance of 0.0002 inches for reliable go/no-go inspection
• Steel construction for durability and dimensional stability under normal shop conditions
• Compact form factor at 0.2 pounds for easy handling at the inspection station
• Individual packaging — no additional components required out of the box

Compatibility

Designed as a fixed-limit plug gage for general-purpose bore inspection of holes nominally sized at 0.321 inches across machined, drilled, or reamed workpieces in metalworking and manufacturing applications.

Installation Notes

Plug gages are inspection instruments, not cutting tools — never force a plug gage into a bore or use it to remove material. Handle with clean, dry hands or inspection gloves to prevent corrosion from skin oils. Store in a protective case away from heat sources and abrasive surfaces to maintain dimensional accuracy. Periodic calibration against certified master gages is recommended to ensure continued measurement integrity.