Polishing and grinding device for mechanical parts

The utility model relates to the technical field of mechanical part machining, and discloses a mechanical part polishing and grinding device which is characterized in that a connecting frame is respectively rotated at one end of a rotating shaft I and one end of a rotating shaft II through a supporting rod, and through a handle and a gear, the distance between two wheels can be adjusted through a rack and an L-shaped fixing block only by rotating the gear; a handle is arranged so that a worker can rotate a gear more conveniently, a first motor is arranged to drive a belt wheel to rotate so that a second belt wheel can drive a first rotating shaft to rotate, and the space between two wheels is adjusted so that the interior of the petroleum pipeline can be fixed; a first rotating shaft drives a connecting frame to rotate, the connecting frame in a second rotating shaft also rotates through a petroleum pipeline, and by arranging a supporting plate, a moving plate and a sliding rail, when a second motor is starte