A motor drive for a rotary medical device having at least one seal-set which comprises a bore defining bearing, a motor having an output shaft, a flexible shaft, having a diameter smaller than the bearing's bore, being power transmittingly and concentrically connected to the output shaft, a seal, defining a bore that is smaller than the flexible shaft's diameter, being mounted adjacent to the bearing with its bore concentric relative with the bearing's bore, wherein the flexible shaft passing through the bearing's bore which sufficiently deflects it to align it with the second bore to interferencingly fit through it and hydraulically seal it.
