An early disc cutting lathe, probably and AM131 made by Neumann, Berlin in the early 1930s, shown here with a DMM master disc. TheDirect Metal Mastering process (DMM) was developed by TELDEC for manufacturing the master disc of vinyl records. The glass at the bottom right of this photo contains the chip or “swarf”, which was cut off during the cutting process of copper masters (normally unbroken, finally with the complete length of the cut groove- the particular challenge of this special dmm-process). Own photograph of a device in the TelDec Museum, Nortorf.
(Note: TelDec is a joint company of Telefunken and Decca founded in 1950)

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