Abstract: The invention relates to a method for producing a rotationally-symmetrical, hollow-cylindrical housing having two magnetizable housing parts arranged to straddle a non-magnetic housing zone thereby isolating the housing parts magnetically. The housing is prefabricated, for the sake of simplified, more-economical manufacture, in one piece from a magnetizable blank except for an excess dimension in the outer diameter (d), and an annular groove which is cut into the inner wall of the housing to the width of the desired housing zone. With the housing rotating, a non-magnetizable filling material is introduced into the annular groove, the vicinity of the annular groove being heated during this process, and the rotation of the housing is continued until the filling material has set. Then the housing is turned down on the outside until the final dimension of the outer diameter (d) is attained and at which time there is then no further connection between the magnetizable parts.