I am in the midst of waterproofing the interior side of my basement. I have many leftover form ties that I've cut off flush with the concrete. The ties originally looked like this:
My waterproofing sealant (Thoroseal) manual recommends I drill into the ties about 1", and fill the hole with some hydraulic cement before continuing with covering the wall with a sealant. In the image below, the dotted circle is kind of where I'd like my hole. You can see the ground down stubs (cut with an angle grinder) from the ties in the middle.
However, I'm not sure how to accomplish this. I tried purchasing a simple carbide-tipped concrete twist bit, but it jumps around when I try to center it on the ties and I can't get it to drill both the concrete and the metal.
Any tips on how I can successfully drill this hole?