Electric machine rotor e.g. for power tool such as grinder

A rotor for an electric machine such as a motor includes a rotational shaft (11), a core (13) having a number of slots running along the length of the shaft (11), a coil (17) running along the several slots and having opposed end sections extending out over the core (13) and a ribbed strip elements (21, 23) made of a layer of material permeable to varnish and plastic and having a number of ribs (23a) provided in an axial direction relative to the rotor (10). The ribbed strip elements (21, 23) is wound around the end second in such a way that the first strip (23b) lies such a way that the first strip (23b) lies nearer the core (13) and is satd. in varnish or resin so that the ribbed strip element (21, 23) adheres firmly on the end section of the coil (17).