12 in which is a connecting rod assembly 13 having an upper universal joint 14 connected to the motor rotor 10 and a lower universal joint 15 connected to a drive shaft 16 which extends downwardly through an elongated bearing housing 17 within the bearing housing 17 are a suitable radial bearings 18 and thrust bearings 19 centralizing the drive shaft 16 within the bearing housing and transmitting weight from the weight means w to the drive shaft 16 as it is being rotated by the motor means m the connecting rod assembly 13 converts the eccentric or orbital motion of the lower end of the motor rotor 10 into concentric rotary motion of the drive shaft 16 the drilling fluid is adapted to be supplied to the motor and drill assembly through an upper inlet 20 at the upper end of the tubular housing assembly passing downwardly through the usual valve 21 through the motor stator and into the connecting rod housing from which it enters the hollow drive shaft 16 through upper port means 22 therein the drilling fluid then passing downwardly through the drive shaft and exiting through the usual bit nozzles as is well known in the case of drills of the type here involved in the illustrated form three of the motor and drill units are revolvably mounted about a central post or shaft 23 and are interconnected by upper and lower connecting collar and bracket assemblies 24 and 24a to an outer shaft or support 25 which is revolvable.