(under subclass 221) Apparatus wherein the work supporting structure is supported to be pivoted about an axis from the first definite position to the second definite position, including an equally divided disk or cylinder (a) fixed to the work support so that movement of the work support is accompanied by a corresponding movement of the disk or cylinder relative to other structure, so that the divisions of the disk or cylinder serve to define the locations of the first and second positions of the work support or (b) fixed to nonpivoting structure such that the divisions of the disk or cylinder serve to define the locations of the first and second positions of the relatively movable work support.
