Pat,
The only things are:
The machine has to have an external motor with a motor mount boss centered under the main shaft.
It is also best to put a spoked hand wheel on it.
Here is my Montgomery Wards 7 Jewel Automatic, URR-988A with and without the hand crank and spoked wheel.
[ATTACH=CONFIG]417004[/ATTACH]
[ATTACH=CONFIG]417005[/ATTACH]
It's the only machine we have that meets all the qualifications. Well, other than being cast iron and heavy.
My wife is going to practice with it using the hand wheel while we look for an aluminum machine to make into the dedicated HC.
Joe