A direct drive servo-valve (10) wherein rotational motion of a drive motor rotor (28) is converted into linear motion of a spool valve (16). The drive motor (26) includes a shaft (50) which has affixed to the end thereof a ball (54) which engages the spool valve. The ball is affixed to the shaft by providing a bore (52) internally of the shaft which is disposed eccentrically to the longitudinal axis of the shaft. The ball has a portion thereof (64, 66) ground off so as to provide an integral protrusion (60) which is received within the bore in the end of the shaft. The ball is permanently affixed to the shaft by brazing the protrusion into the bore and a planar surface (62) which surrounds the base of the protrusion to the end of the shaft against which it mates.