Flintstone, vises take an eternity, and often multiple processes. There is about an 18 month saga of getting a Wilton apart on a site I'll not name for many reasons. It began with the electrical process. It eventually welt into a long soak in Diesel fuel and finally came apart with force applied in a press. The very nature of a vise tells you time will be required.
Nola, I'll give you a homework assignment.
Look at a concrete mixer frame. Also look at a pottery wheel.
A power driven positioner is only necessary in production welding. A positioner that holds at strange angles is damn valuable a lot of days.
Take a good look at how the planetary drive works in a snowblower. It will make an excellent drive unit with a drill motor, and most snowblowers go to China with the drive in fine condition.
I've built a few field expedient positiners, and they are a walk in the park if you think a little bit.
Offer the guy scrap price for the chuck after he lugs it to and from the flea market, and he'll probably give it to you. THEN, go to work on it.
Some Diesel fuel will probably free it up and you can blow away most of the rust easily.
Either molasses or Citric acid should be your first choices, in that order.
Once you get it cleaned up, you can offer it for sale on sites like Practical Machinist where people salivate for such huge chucks.
Worst case, if it doesn't sell you have one hell of a positioner chuck. In time to come you will be very happy to have it.
Take advantage of your ability to learn and think now, so you don't grow old taking orders from someone who learned to think.
