Possible repair suggestions

[69L72RS]

I wanted to see if anyone has a suggested repair method for the following problem.

I have a BE rear that someone welded the posi to make it a spool. I would like to keep the original unit with the original rear.

Right now my only idea it to go at it with a die grinder and a lot of time.

I don't want to use a plasma cutter or torch.

I have had one suggestion of using a CO2 busrt and a hammer to shatter the spiders. I don't know if this would crack the case too. I think the case is made of cast steel.

I know it might end up being a junk case anyway, if the case relaxes after the weld stress is removed, but I want to give fixing it a try anyway.

Thanks in advance for your help.
Eric