Waterpower cutting knife (casing cutter) is able to bear drastic vibration when cutting multilayer noncentric casings. Thanks to its unique structure, burly slicer arms can extend as far as five times of its diameter to obtain maximum stability under all kinds of unfavorable cutting conditions (including hard spot, decentration,discontinious incision etc.). For example, the diameter of 13 3/8" casing cutter is only 11 3/4", but the diameter of casing of all kinds of weights it can cut exceeds 60".