Abstract: The present invention is related to a heating apparatus for rings or the like. A U-shaped core is placed in a case such that the ends of the two core legs can project therethrough. A primary coil is placed around a portion of the core that is within the case. A ring or the like which is to be heated and expanded is placed over the one core leg such that it rests on the outside of the casing, and a bridging core is then placed on the two legs such that the legs are bridged and thereby a loop core is formed. The core is energized causing the ring to be heated due to the electrical resistance therein. The bridging core is readily attachable and removable from the legs thereby enabling a ring to be easily placed onto and removed from the apparatus. Further, in some embodiments an adjustment means is provided to enable the core to be radially or vertically adjustable.