Jewel balls are made of synthetic sapphire/ruby. They are largely used in heavily corrosive environment and optical fiber communication because of its anticorrosion, wearable and fine transmission characteristics.
Jewel blind holed balls are used as insulated measure head on precise instruments. Specification
Diameter: F0.80 ~ F12.00mm(sapphire), Max deviation of diameter: ±0.00127
Diameter: F0.60 ~ F8.00mm(ruby), Max deviation of diameter: ±0.00127 Technical Index
Material: Synthetic sapphire/ruby (a-Al2O3)=99.99%
Tolerance of Diameter: 0.00125mm
Surface roughness: Rz0.1
Roundness: 10Grade~50 Grade
Surface quality S/D: 40/20