Hi Dave, I use a Dewalt DW541K Rotary Hammer Drill. 3/4" ground rods are no problem for it. It will take a 1 1/2" bit and I have dry cored 4" holes for Wiremold poke thur floor boxes. I also use it as a chipping gun. The company I work for has about 50 large hammer drills. A combination of Dewalt and Bosch. They used to buy Hilti but don't anymore. I believe the reason is price.
