Wise chain padlock

[candado3]

I posed this on another forum and did not get any satisfactory answers so thought I would try here.

I have this old wise chain lock that I was not able to open because the outer larger ring was frozen and would not budge no matter what I tried. So I decided to take it apart to see what the problem was. I now have an answer but also a question.

The outer, large ring, was frozen to the housing so firmly that I had to fashion a flat tool that fit into the key slot and hammer it into the slot against the outer ring in order to drive the ring out. It took some hard knocks and I had to force it all the way out in this way. The other outer ring in the other part of the housing is also firmly stuck and won’t budge.

My question is. Does anyone have any suggestions on how I can fre this ring without destroying it or the lock. I would like to salvage the lock and possible hold it together with a screw of some kind. I have tried soaking the lock in penetrating oil, freezing the lock to see if the different metals would contract differently, freezing and then boiling the lock to see if that would loosen the ring but nothing has worked. As you can see from the photos there is very little of the ring protroding so nothing to grasp.

Thanks for any suggestions that you might offer.