Cylindrical records were hard to duplicate. How do you release a grooved cylinder from its one-part mould? The problem was eventually solved with shrinking wax, but meantime multiple editions meant recording the same piece many times or using a duplicator like this. Master and blank rotate together while the movements of the pickup stylus are conveyed via levers to a cutter which makes the duplicate. The machine could produce twenty copies an hour, though quality could be poor and the master soon wore out.
© Science Museum / Science & Society Picture Library