Spi 12-740-7 Chrome Steel Gage Ball 21/32 Inch Grade 25

Product Description

The SPI 12-740-7 is a chrome steel gage ball designed for precision measurement applications. It features a diameter of 0.6563 inches (21/32 inch) with a tight tolerance of 0.0001 inches, meeting Grade 25 accuracy standards. The ball is hardened to 63 RC for long-term wear resistance and dimensional stability. AFBMA certification confirms it meets established industry standards for ball accuracy and surface finish. This type of precision ball is used by tool-and-die makers, quality control technicians, and metrology professionals who require repeatable, accurate gauging references.

Chrome steel gage balls at this accuracy grade are used in calibration labs, inspection departments, and machine shops. They serve as go/no-go gauging references, bore gauging inserts, and precision spacing components in fixtures and jigs. The Grade 25 classification makes this ball suitable for demanding dimensional inspection tasks where surface finish and sphericity are critical. This part is sold individually.

Key Features

• 0.6563 inch (21/32 inch) diameter for precise dimensional fit
• 0.0001 inch tolerance for high-accuracy gauging applications
• Grade 25 accuracy classification per AFBMA standards
• AFBMA certified for surface finish and sphericity compliance
• Hardened chrome steel at 63 RC for durability and wear resistance
• Sold as a single unit to minimize unnecessary inventory

Compatibility

Designed as a precision gauging reference ball suitable for use in bore gauges, inspection fixtures, and calibration equipment requiring a 21/32 inch diameter Grade 25 chrome steel ball.

Installation Notes

Precision gage balls should be handled with clean, dry gloves or non-marring tools to prevent surface contamination that could affect measurement accuracy. Store in a clean, dry environment away from corrosive materials. When used in inspection fixtures or gauging assemblies, verify seating surfaces are free of debris before use. Follow applicable metrology lab procedures and AFBMA guidelines when incorporating gage balls into calibration routines.