The invention belongs to the pump elements and the pump-element-based dosing pumps, to fabrication of devices and parts thereof, in particular, to the method of machining of cylindrical surfaces of parts of aluminium-oxide-α-modification-based crystal.The pump element comprises the external and the internal parts of aluminium-oxide-α-modification-based crystal, preferably of leucosapphire single crystal, with roughness Ra of contacting working faces of 2-5 angstrom. The surface smoothness is achieved by the machining method comprising drilling of parts preliminary workpieces of crystal using diamond tool, three-step machining of surface with diamond tool in the presence of lubricating fluids with successive reduction of abrasive grain size, relieving of internal stress in workpieces through annealing in the muffle furnace, surface machining with semi-soft or soft polishing wheel or lap with diamond grain size of 5/3 um and/or 1/0 um on clock oil, surface tribochemical polishing with colloidal-SiO2-based polishing compound.This invention allows increasing service life of pump elements as components of dosing pumps, and prolonged maintaining of dispensed liquids dosing accuracy due to rubbing surfaces friction coefficient reduction.
