MiamiCuse wrote:


I do have a hammer drill. The holes are roughly 4" in diameter.

I am just worried that if I drill through and I cannot pull the concrete
out, and I have to break it into pieces it will drop down into the pipe.


I would think the pipe down below has covers on the holes and the sheet
metal tubes were a crappy idea for future access. If you are still
worried then rent a 6 inch masonry hole saw and after the outside blade
starts to cut a circle in the concrete, stop and remove the center pilot
bit of the hole saw so it doesn't drill through the drain plug.

Tony