Concentricity measuring device for large cylinder

The utility model discloses a concentricity measuring device for a large cylinder. The device comprises a horizontal base, two cylinder placing frames, two guide rail frames, two linear guide rails, two measuring meter seats and a linear square key, the two cylinder placing racks are used for placing and fixing a to-be-measured cylinder. The two guide rail frames are correspondingly and fixedly arranged at the positions, located at the two ends of the linear square key, of the horizontal base. Wherein one linear guide rail is horizontally and fixedly erected at the top ends of the two guide rail frames, the other linear guide rail is horizontally and fixedly positioned on the upper surface of the horizontal base, and the two measuring gauge stands are respectively and correspondingly arranged on rails of the two linear guide rails in a sliding way. Compared with two thimbles, the barrel placing frame has the advantages of being convenient to assemble and disassemble and reliable in positioning, the effect is