I am looking for recomendation for good drills for bolting granite. Specific model name/numbers would be helpful so I can try to find one for a good price. Also if you know please let me know the average # of 3/8"x3" holes one battery will drill in granite. EDIT: I am looking for a rotary hammer not hammer drill. I got a hammer drill and tried using it...FAIL! Hahaha. Thanks In Advance!