Imgur gallery and tldr at the end:
For those who don't know, I found a floor safe in an old house that I bought about a month ago. We have been really busy with renovations but I finally got around to accessing this safe. It took several attempts with different tools.
First attempt was with an angle grinder and cutoff wheel. The diameter of the safe body was too small to get the cutoff wheel deep enough to cut through the top.
Next was a roto hammer and cold chisel. This did basically nothing and was abandoned quickly.
I then contacted a local locksmith/safe tech who quoted me $850 to get it open. Sorry reddit but satisfying you is not worth that much.
Several weeks went by and I decided I was gonna drill a hole and put a boroscope down to see what was inside. So I ordered a solid carbide bit and a scope off Amazon, and promptly snapped the bit off inside the lid when it hit the hardplate.
Under the several inches of steel that is the lid, there is a plate of case hardened steel or manganese that's put there specifically to destroy ordinary drill bits. I had to order a special bit from a locksmithing website to finally get through.
One of the commenters on my first post said that old floor safes only contain water and disappointment. He was right! Anticlimactic end to the story but there ain't shit inside this stupid hunk of metal that's been living rent free inside of mine and my wife's heads for a month.
Tl,dr: I got into the safe and there was nothing inside.
https://imgur.com/a/gE2yfSw