Abstract: A synchronized device for welding contact pieces onto support material. The device has two electrodes mounted on a housing. The contact pieces and the support material can be separately fed between the electrodes. At least one of the electrodes has an electrode insert for engaging a contact piece resting on the surface of the support material to which the contact piece is to be welded. The electrode can turn around a longitudinal axis which is substantially perpendicular to the surface of the support material to turn a contact piece between the support material and the electrode insert to a desired angular position with respect to the support material. Turning of the electrode is synchronized with the other parts of the device.