Hi John,
I'd safely say that these are pretty well finished and either you fabricate new ones or simply toss that chassis into the scrap bin and find a better one to work with. These machines are not rare and there's still bucket loads of them out there to be had.
Maybe it's best that this one becomes spare parts for another as that's what's happening with many bad ones due to the ridiculous prices of all the consumable components required.
Sadly as these rails get worked and reworked again and again using heat the steel becomes rather soft and it's pointless mucking around with it any further
If this other guy in Perth is able to fabricate new rails and stitch them into your side plates then that will be the best option I'd say.
All in all this chassis as it stands is now considered as compromised.
Cheers,
BB.
