I figured I would have to make a boss. I'd probably use aluminum since it's soft though a harder wood like oak might work as well and would be easier to work. Wood may actually be the better way to go. Once it was mounted and painted no one would be able to tell anyway. I don't think strength would be an issue.
I think I would drill and tap the machine column that way I can access everything from the outside.
The other choice would be to make an adapter that mounted to the base and mount the crank to that so the machine itself isn't touched. I can't think of any reason not to modify a reproduction handcrank if I need to.
Rodney
Rodney