A carriage assembly includes a housing having first and second pieces each defining a recess that has a bearing surface with raised dimples. The first and second pieces are assembled to each other such that the recesses are aligned to form a cylindrical hole. A bushing is received in the hole and has an outer surface disposed against the dimples of the first and second pieces. The dimples are deformed during assembly to secure and locate the bushing within the cylindrical hole.

A carriage assembly includes a housing having first and second pieces each defining a recess that has a bearing surface with raised dimples. The first and second pieces are assembled to each other such that the recesses are aligned to form a cylindrical hole. A bushing is received in the hole and has an outer surface disposed against the dimples of the first and second pieces. The dimples are deformed during assembly to secure and locate the bushing within the cylindrical hole.

A portal-type positioning device includes two parallel linear guides provided with integrated linear drives, which support a separate X-carriage in a manner that allows movement in the X-direction, as well as a cross beam which is connected to the two X-carriages and movably supports a carriage in a Y-direction that extends perpendicular to the X-direction, with the aid of an integrated linear drive. In addition, the positioning device has a tool holder, which is guided on the Y-carriage in a Z-direction and holds a tool for machining a workpiece situated in an X-Y plane, the tool being disposed next to the cross beam at an offset in the X-direction. A force frame disposed above the tool in the Z-direction transmits a process force acting on the tool to the carriages LX1, LX2 without deforming the cross beam by a torque. The process force is applied by an electromagnet which acts between the force frame and the tool holder.