Abstract: A planar workpiece of polygonal outline, such as a metal frame for use as a spacer in thermally insulating glass is stood on its edge and transported to a manipulator which tilts the workpiece about a horizontal axis to position one of its corners in a treatment location where it can be, for instance, soldered or brazed. Thereafter the workpiece is tilted over and set on an edge and either transported away to another such treatment location or positioned with its next corner in the same treatment location. The manipulator which tilts the workpiece in an upright position can be a plate with four sides or a pair of arms pivotal between horizontal and vertical positions.