... area: 1. Hydraulic pressure and pneumatic parts field: valve, fairlead, gear wheel and piston;2. Machine tool parts: sea saw, ... guiding rail, worktable and transmission gear;3. Metallurgy machine parts: the transporting ... : gear, gear box etc.7. Weave and printing machine parts: roller, axis, gear and flange;8. Train making fields: dowel ringer ...