Abstract: A cylinder rounding/holding tool that is positioned in the center of the rotary table and bolted to a base plate for rigidity. The tool is formed from a metal frame that is circular on the inside diameter to form a locating boss and has flats on the exterior corresponding to the number of shoes required for the application. At each flat is a shoe that has two mechanical jacks (one at each end of the shoe) and a center guide tube. The jacks are powered by DC electric stepper motors that allow precise radial displacement of the shoes. The center guide tubes provide circumferential and axial load carrying capability and stability for the tool. The shoes are replaceable to allow machining to match the inner diameter of the cylinder being rounded. A computer controller may be used to control the stepper motors and a linear variable displacement transducer may be used for input to the computer controller and a real time feedback loop for roundness condition of the cylinder.