At my property I would like to get a 1-2" hole 8 ft deep. The only problem is, I start hitting rock (hard sandstone) about a foot deep.

Is there some kind of shank extension for a rotary hammer that I can use to get down there? I have ground rods in a trench, and they're okay, but I really would like to see if I can get one to 8 ft.

closed as off-topic by mmathis, ThreePhaseEel, Daniel Griscom, Machavity, Tyson Mar 15 '18 at 16:23

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The roto hammer is not designed to drill any where near that deep. You can try to drive the ground rod with the roto hammer. They rent an attachment. If it is indeed sand stone and not too hard it may drive it through. Other wise be content with the trenched ground rods. This method is widely and successfully used. You could contact a highway construction company and find out the going rate for a rock boring drill.

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