Other Machinery Parts,Construction Equipment Parts,Earthmoving Parts,Hyundai Machine Parts JINING SHANTE SONGZHENG CONSTRUCTION MACHINERY CO.LTD , https://www.sdkomatsudozerparts.com 1. What are the main contents of GB157-89 "Taper and cone angle series"? A: GB157-89 is equivalent to ISO1119. The standard specifies six terms and definitions, as well as general-purpose cones, taper and cone angle series for special-purpose cones. Suitable for smooth conical parts, not for conical parts such as pyramids, taper threads, bevel gears, etc.