GRUPP (Wilhelm Grupp) WF1 Precision Universal Milling Machine. Operation & Maintenance Manual GRUPP (Wilhelm Grupp) WF1 Precision Universal Milling Machine. Operation & Maintenance manual with electrical schematic. GERMAN TEXT. This manual, although perfectly readable, is not to our usual high standard. Manufacturers: Grupp Models: WF1 Contents: Operators Manual Maintenance Manual Electrical Diagrams