Drill press

I would find someone locally with a lathe. Take all the parts you have and get a new one made. Since that one appears to rotate in the bearings, it is likely not critical for alloy or hardness

What is wrong with the old one? Could it be brazed/ welded / built up and re-turned? could it be turned down smaller and bushed back up again?

Don't discount the idea that you might turn it smaller and then use a bearing(s) with smaller ID, same OD, whatever, etc