Method and apparatus for making superconductive magnet coils

A method of making a curved generally pancake-shaped coil adapted to be mounted around a 180-degree segment of a cylindrical support,

• such method comprising the steps of providing a tubular mandrel having a tubular cylindrical substantially rigid mid-portion terminating at both ends in tapered tubular end portions formed with a multiplicity of longitudinal slots providing flexible fingers between said slots,
• providing an elongated oval shaped pole island in engagement with the outside of said cylindrical mid-portion and parallel with the axis thereof,
• winding an elongated electrical conductor around said pole island to form a multiplicity of generally oval shaped turns in engagement with a 180-degree segment of the outside of said mandrel,
• said turns having longitudinal portions with curved portions extending therebetween,
• the curved portions of at least some of said turns engaging said tapered end portions of said mandrel,
• providing tapered expansion members of circular cross section for expanding said tapered end portions, and
• inserting said expansion members into said tapered end portions of said mandrel and thereby displacing said flexible fingers outwardly into a generally cylindrical form so as to displace said curved portions of said turns into a shape conforming to said cylindrical form while also exerting increased tension upon the turns of the coil to minimize draping of the longitudinal portions of said turns and to enhance the mechanical integrity of said coil.