Walt.
No flame wars. That’s true. It doesn’t have to be true level. But if you were to use a level. What would you do, shim the level, until your got a reading on the bubble, or adjust the machine till it was on the level plane?
On a side note. I was watching some Mazak techs a few months ago, doing a 12 month follow up, on a 6 meter H650e Integrex. Their preferred method was to take a sheet metal cover off near the milling head, lay some Play Doh down on some sheet metal guard, close to the head. Press the level into that until they got a reading, and proceed to tune the machine up, based on results coming from a level pressed in to Kiddies Putty, as they traversed the base.
It didn’t look that confident to me. That machine has never turned parallel also.
Regards Phil.