Method and apparatus for making superconductive magnet coils

A curved, shell type magnet coil, adapted to be used in a superconducting magnet, is wound by providing a mandrel having a tubular cylindrical midportion terminating at both ends in tapered end portions formed with longitudinal slots having flexible fingers therebetween. An elongated electrical conductor is wound around an elongated oval shaped pole island engaged with the outside of the cylindrical midportion, to form a multiplicity of oval shaped turns engaged with a 180 degree segment of the mandrel. The coil turns have longitudinal portions with curved portions therebetween, engaging the tapered end portions of the mandrel. Upon completion of the winding, tapered expansion members are fully inserted into the tapered end portions, to displace the flexible fingers outwardly into a cylindrical form and to displace the curved portions of the turns into a shape conforming to such cylindrical form while also exerting increased tension upon the turns to minimize draping of the turns and to enhance the mechanical integrity of the coil. A half cylinder clamp may then be employed to clamp the coil, whereupon the coil may be solidified by the use of an epoxy adhesive.