Devices for exactly positioning a workpiece and a tool machining the workpiece

An apparatus for machining a workpiece to create a manufactured article having a desired configuration, which apparatus comprising:

• a rotary worktable on which the workpiece is held,
• a machine tool which engages the periphery of the workpiece on the worktable to remove material therefrom to shape the workpiece,
• a first device associated with the worktable to rotate the workpiece so as to precisely position it with respect to the tool, and
• a second device associated with the tool to precisely position it with respect to the workpiece as it is rotated,
• wherein said first device includes a slider coupled to the worktable to cause the table to turn clockwise when the slider is advanced in one direction, and to turn counterclockwise when the slider is advanced in a reverse direction, and
• wherein an advance of the slider is effected by a pair of drums, one being linked by a flexible metal band to one end of the slider, the other being linked by a flexible metal band to the opposite end of the slider whereby when the drums simultaneously rotate, the slider is caused to advance in a direction that depends on the direction of drum rotation.