I was trying to jack hammer a hole through my foundation. This turned out to be a herculean task. I blame the old concrete from 1950 which is filled with rocks. I keep getting my bits stuck in the foundation. What's the best way to get them out?

Is there a chemical or something that you can spray around a bit to help free it? Is this something I should try next time?

2 Answers 2


I'm not going to mark this answer as chosen, but in order to get my bits out what I ended up doing was taking the big (1-1/8-hex bit) demolition hammer, the one that got the first pointed bit stuck and I removed the demo hammer from the bit that was stuck in the ground. The hammer came with another flat-chisel bit which I was able to use to free the pointed-chisel bit.

In the process though I put a lot of wear on the flat-chisel bit since I basically had to chisel down the top and the bottom of the flat-point bit.

  • why asking a question if you have the answer
    – Traveler
    Jul 3, 2023 at 0:54
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    @Ruskes For the same reason I said I wouldn't mark the answer as chosen: because I'm not satisfied with it. It's a starting place. And for the same reason there are other parts of the question not in the answer "Is there a chemical or something that you can spray around a bit to help free it?" But, even if I had an answer and didn't want further input. It's encouraged to ask and self-answer: stackoverflow.com/help/self-answer Jul 3, 2023 at 1:02
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    Self-answered questions are not only perfectly acceptable here, @Ruskes, they're actually encouraged!
    – FreeMan
    Jul 3, 2023 at 1:13
  • To the question itself, I don’t have an answer. I’d suggest a strategy of push/ pull/ clear debris to keep this from happening in the first place. Jul 3, 2023 at 3:12
  • You might also try drilling multiple holes with an actual drill bit and then trying to break the web between them with a chisel. Jul 3, 2023 at 3:14

Just had several holes drilled through concrete: 3 at 2" diameter and 1 at 4" and then 2 at 7" in diameter.

These were done with a type of pillar drill and big core drills - all very clean holes, the setup time was about 10 minutes as a bolt needs to be used to secure the pillar drill. Each hole of 7" through a thickness of 10" took about 5 minutes.

I hate to think how long it would have taken to drill drill multiple smaller holes around the diameter...

This link shows the model of drill they used:

  • 2
    Doesn't answer the question.
    – brhans
    Jul 3, 2023 at 7:45
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    @brhans yes it does - use the correct tool for the job :)
    – Solar Mike
    Jul 3, 2023 at 7:46
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    This is a reasonable answer for "how do I make a large hole in my concrete floor", but it doesn't address the OPs current issue (possibly due to using the wrong tool) of "how do I unstick the bit?".
    – FreeMan
    Jul 3, 2023 at 15:00

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