The way I'd do it is clean it all up preheat the case to about 250-300f weld it up peen it with a ball peen hammer all over the weld area, weld again, slow cool to room temp under welding blankets and then grind to shape, re drill and tap and use an engraver / needle scaler to reapply the cast...
These are generally done with oxy acetylene using an inline gas fluxer. Theres a few shops still doing it.
That being said If you plan on making another run consider making yourself an expanding heat sink like they use in bicycle building for the warpage of the head tube...
The only way ive found to get good tubing cuts on a portband is a saw guide like ones from Techsouth. Ive done tons of sanitary tubing that way. That being said for cutting elbows I would get one of those holding jigs and use that as a cut guide in a horizontal saw. TICON makes a fancy $$ one or...
I don't have any of those super long cups myself. In this instance i'd run a large cup like a Furick *** thats made of glass to get a better viewing angle but also large enough to run a long stickout. In some real tight circumstances Blue Demon makes bendable tungstens.
Pferd robust grind CC imo. That being said I'd still use a scarfing tip to get it down tighter first.
Hypertherm makes a nice flush cut attachment as well if you had one of their plasma cutters.
https://www.garagejournal.com/forum/threads/years-that-snap-on-first-gen-4-side-handles-were-made.75662/ perhaps this thread may interesting to you.
as well as this website https://collectingsnapon.com
With the production of these 3/8 head 1/4" body ratchets lately I pretty much never grab 1/4" drive anything anymore. Very uncommon I can't fit my 3/8 stuff now. I even use 3/8 impacts for lugnuts usually cause its whats on hand.
Not a big helicoil fan myself Keenserts are where it's at but overkill in this application. Far easier to just drill out and tap to the next size up since it looks like the hole in the sheet metal is already plenty large.
If this came to me to be done I would cut out the existing bracket completely and replace it with a newly designed one from Send cut send or similar Tig weld in, Then machine/ shave the swing arm itself down to fit the frame.
Dealing with the warpage possibilities from plugging the original hole...
In my experience aluminum or stainless is the way to go for animal cages. But the only animal cages I have experience are in a lab setting which needs the more robust materials. That being said last Stainless countertop I did I bonded to the below plywood with Loctite PL Premium Max and it's...
100% i'd use a pre drilled mounts with a most likely ground shaft at the correct diameter from MCmaster or similar to hold the two concentric the whole way through. It can be done other ways but this is how i'd do it.
Standard panel bond like 3M 38315 would work plenty for this application. The only downside being you need the special applicator gun
JB weld 50139 would be the most cost effective being that it doesn't require an applicator and is relatively affordable.