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Koyo Metric Inner Rings for HK Needle Bearing

Koyo JR Series Metric Inner Rings
When it is impractical to meet the shaft raceway design requirements (hardness, surface finish.) These inner rings are made of rolling bearing steel and after hardening, their bores, raceways and end surfaces are ground. Metric series inner rings may be used to provide inner raceway surfaces for metric series radial needle roller and cage assemblies, metric series needle roller bearings. The extended inner rings are suitable for use with bearings containing lip contact seals and for applications in which axial movement is present. 
JR Series have chamfers to assist in bearing installation but are without lubrication holes. Inner rings of series JR.JS1 and IMC have bearing installation chamfers and lubricating holes (bores diameters 5 to 180 mm (0.1369 in to 7.0866 in). Inner rings of series JRZ. JS1 are without installation chamfers, allowing for maximum possible raceway contact.