Yet I haven´t worked with either machine so I don´t know much about the internal technical details. I know there are dedicated synchronized binder machines of either type. My question is if it possible to convert lets say an Adler 69-373 (or Pfaff 335 equivalent) into synchronized binder machine? I mean do all the machines factorywise already have the synchronizer mechanism thats is probably just covered by the arm cover? Or with other words - can I remove the plain arm cover and replace it wi