A new type of multi-chopper (22) for cutting strands or ribbon shaped material such as strands of glass fibers, and a method of using this chopper, is disclosed. The chopper has at least two chopper assemblies on a rotating frame (50,350). When one chopper assembly needs repair, the frame is rotated which brings a rebuilt or repaired chopper assembly into operating position quickly and also brings the assembly needing repair into a position where it can be worked on while the other chopper is operating resulting in much reduced downtime. The frame of the chopper can rotate around a vertical (26) or horizontal (141) line, or around a line passing through two opposite corners of a frame.