Abstract: An first induction hardening coil assembly according to one embodiment of the present invention comprises a coil having a top surface, an underside surface, and an inner coil curvature disposed between the top surface and the underside surface. The inner coil curvature extends approximately 180 degrees around a coil axis. The coil further includes a first end section adjacent a first end of the inner coil curvature which extends between the top surface and the underside surface. A second end section adjacent a second end of the inner coil curvature extends between the top surface and the underside surface. A support arm is connected to the coil and is constructed and arranged for providing an electrical connection between the coil and a source of electrical current. The support arm includes a current-in portion connected to the underside surface adjacent the first end section and a current-out portion connected to the top surface at a location which is between the first and second end sections.