Wheeler-Rex 7800 Earthworm Hydro Drill The Wheeler-Rex Earthworm Hydro-Drill bores holes underground without the need to trench or disturb surface materials. It is ideal for installing water, gas, drain, and electrical lines and comes standard with a combination drive/water valve assembly, and a 2″ diameter auger. (User supplies 3/4″ pipe for drill shaft.) Additional Augers (sold separately): 7801 1″ (25mm) Auger 7810 3″ (75mm) Auger 7808 4″ (100mm) Reversing Auger 7809 6″ (150mm) Reversing Auger Grounding Instructions: Install ground wire before using drill (Grounding wire is included). Clip one end of wire on the water valve stem. Clip the other end to the top of the ground rod or steel pipe (user supplies). Drive rod at least 12″ into the ground several feet from the operator.