Originally Posted by
hanermo
1. No.
2. Yes.
Concrete, and derivations, are pretty weak in terms of strength, bending, and rigidity.
They are strong in compression, and good in vibration resistance.
A mill C frame, like a BP (old, 60 year old design), or a VMC (modern) has about 30-40 cm D thickness on the column.
Forget anything like 6".
Basically, concrete, granite, marble, etc are about 3x less strong and rigid than cast iron, and steel is about 1.5-2x "stronger" than cast iron.
You "could" make a very good mill from concrete derivates, granite, etc. by simply upsizing the column to 60 cm.
But if it had a steel skin it would be much better.