An electromagnetic coil assembly comprising a spool-spindle and a case. The spool-spindle comprises a spindle portion and a larger included portion. The spindle portion has a conductor wound thereon. The larger included portion has opening for receiving the conductor. The case has a first case end and a second case end, with an opening extending through the case. A first internal surrounding surface extends from the second case end and a second surrounding internal surface having a smaller diameter extends from the first case end. The first internal surrounding surface meets the second internal surrounding surface at an annular internal wall. The spool-spindle is positioned in the case until the larger include portion abuts against the annular internal wall, and the case and spool-spindle are joined.