Abstract: Apparatus for supporting and guiding a machine for operating on sheet material such as cloth while the material lies on a surface of a supporting structure having a pair of substantially parallel sides extending lengthwise of the structure, the apparatus comprising a carriage adapted for movement lengthwise of the supporting structure along a path substantially parallel to the sides, a guide arm on the carriage extending across the supporting surface between the sides and spaced from the surface, and a support arm connected to the guide arm extending at an angle thereto and located in spaced relation to the supporting surface, the support arm carrying at one end a machine for operating on the sheet material, and the support arm being pivotally movable about an axis substantially parallel to the longitudinal axis of the guide arm and along a plane disposed substantially perpendicular to the supporting surface.