Guide hole is in a horizontal direction at hole opener drilling a predetermined angle and drilling holes in a predetermined cross-section, including a straight slash and some large radius arc. Drill pilot holes at the same time, the contractor may choose and use larger diameter drill (ie irrigation tube) to shield the guide rod. Rinse the catheter tube may play a similar role, can also facilitate retracting the guide rod and replace the drill bit and so on. Direction of the guide hole is controlled by a controller located at the rear end of the drill pipe within the drill bit (called bent housing) is completed. Drilling during the drill is not rotating If you need a change of direction bent housing right position, bore path that is right along a smooth curve forward. Drilling curves by placing the rear end of the drill pipe in the drill of the electronic direction finder is measured and then the results transmitted to the surface of the receiving device, the data is processed and calculated in digital form displayed on the screen, the electron means primarily intended for monitoring the relationship crossover drilling between the drill pipe and the earth's magnetic field and the inclination (bit three-dimensional coordinates in the ground), the measured data are compared with the design data, to determine the deviation of the actual position and the design position of the drill, and the deviation value within an allowable range, and so on until the drill pilot holes in accordance with a predetermined curve unearthed at a predetermined position.