WMW (UNION and SAALFELD) Round Column Drilling Machine B20-A/1. Manual WMW (UNION and SAALFELD) Round Column Drilling Machine B20-A/1. Detailed Operator's Instruction and Maintenance Manual with Electrical Schematics and a sectional drawing through the head. Manufacturers: WMW Union Models: B20-A/1 B20-A1 B20A1 Contents: Operators Manual Maintenance Manual Electrical Diagrams