A topping or rounding off tool. These machines were used for slightly reducing the diameter of and/or truing up wheels which were not running true. They were also used for shaping the teeth of wheels which were being made. After radial slots had been cut into the outside of a wheel, leaving square-shaped teeth around the circumference, the topping tool, used with appropriate sized and shaped cutter, shaped the ends of the teeth to the correct curvature. The selected cutter, of the exact shape of the required space between two adjacent teeth, had an adjustable part offset to one side, set so that it entered the space between the next two teeth of the wheel. With each revolution it pulled the next two teeth of the wheel into position to be shaped. Each revolution of the cutter advanced the wheel by one tooth.