My old house has a crawl space with two dug cellars, both of which leak in ground water during heavy rain events...both have an undersized sump pit and a sump pump.
BUT...
If I had a newer house that had a mostly problem free basement with more space than I think I needed...I'd add a walk-in gun vault, maybe 6' by 6', cement walls and strong steel door.
If you are putting metal machining equipment down there, I can only assume your basement is mostly problem free, in regards to moisture?