In my area, there are lots of cabinets (w/out machines) for sale for very little, usually $15 or so. I suppose people didn't need/want/understand the machines, tossed those, and kept the tables to be used as furniture. Imho, unless the cabinet is a genuinely nice piece after a refinish, I'd just buy a "new" one for a low price, hide a few scratches (they all have a few) and be done with it.
Both of your tables look OK, especially the treadle. The 66 cabinet is one I'd doctor a little to make it look presentable but I wouldn't invest time and effort with a complete refinish unless I really liked it.
My $0.02.