How to Put a Hole in the Wall...

Core drilling can be a easy enough task..."can be".

If this foundation is loose laid stone and there is wiggle movement of any one stone to be drilled through it would quickly bind and slow and even stop the bit rotation.

All the you-tubes shown were stable one piece concrete with no shifting stones.

It only takes one stone to move/shift a smidge and it's a show-stopper...and then there is trying to get the expensive bit back out from in the hole.

If your wall is massive 18" thick single squared up sandstone blocks then no problem...will cut like butter...just hold the tool steady so not drilling a arc/curved hole during the whole drilling time. And oversize that hole size and patch around is more forgiving than snug.

With all due respect, I feel you are spinning your wheels trying to core drill laid up stone. Not only could it bind the drill, it has the potential to break your arm. Done a ton of masonry over the years, & the only way I see it is to start at the top & tooth out the stone to the desired depth & width. Once you get the top relieved, it shouldn't be too bad. Once you get the rough hole established, then re tooth the sides with what you removed. once complete, you are ready for a door.
Jim

JP, how/what progress ya makin on this? Don't think you're gonna post & then disappear!! Ya got some of us mason people curious.

Taking wall apart stone by stone is how did mine. It was not that difficult also when I relaid stone I built a angled shoot into the wall 4 -5hour job. But before you do that consider when getting you delivery have the hauler use a longer shoot to deliver coal farther into bin. I also use roof shovel to pull coal into the bin as it is comes down the shoot. My bin is 5x12 with opening on the shortside

What??? no pix?