You need to rent or purchase a good hammer drill. You also may be
encountering rebar.


s


"willshak" wrote in message
...
X-posted to other relevant group.

Before there were concrete drill bits, or electric drills for that matter,
small round holes in concrete or rock were made by a round chisel type
tool that was pounded into the stone with a small sledge hammer while
turning the tool. It might have been 8" or 10" long. The face of this
chisel had a star-like pattern, only with 4 points, like a plus sign " +
". I believe it was called a star drill.
A Google search brings up a lot of sports drills (training regimen).
Anyone know if they still make them, or if so, where to get one on-line?
I'm trying to drill some 40 - 3/4" holes in concrete and my 1/2" corded
electric drill with a concrete bit stalls on the stone aggregate in the
concrete requiring me to stop and try to crack the aggregate with a large
punch. I figured a star drill would work better.

--

Bill
In Hamptonburgh, NY
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