Universal rear cover three-jaw clamp

The utility model discloses a universal rear cover three-jaw clamp which comprises a flange plate and a conversion disc arranged on one side of the flange plate, a disc is arranged on the side, away from the flange plate, of the conversion disc, a supporting base is arranged between the disc and the conversion disc, and the supporting base extends in the axial direction to be provided with jaw parts. A circle of first threaded holes and a circle of second threaded holes formed in the inner sides of the first threaded holes are formed in the disc, a first through groove and a second through groove are formed in the outer side and the inner side of each claw part respectively, and a first fastener and a second fastener are arranged on the first through groove and the second through groove respectively. The first fastening piece and the second fastening piece penetrate through the first through groove and the second through groove correspondingly, then different first threaded hole positions and second threaded