Abstract: Apparatus for radial drilling into selected formations adjacent an earth borehole, the apparatus consisting of concentric, counterwound spring shafts operating in conjunction with a rotary drive source and a guide housing positionable to direct the rotating bendable shaft down and outward in a radial direction. The apparatus includes bit weight limiting means and guide housing locking means which enable effective radial drilling operation in any selected angular and/or radial directions to greatly multiply and enlarge the producing formation interface.