Nick, my first action would be to talk to Tony Betts about the possibility of replacement radius arms in good nick. Only if these are not available would I attempt a decent repair. There isn't usually too much of a shortage of Ruby bits.

Ian Mc.

Location: Shropshire

I recut the thread 20 years ago with 5/8th or9/16ths die nut.
Still holding together
The other side is moŕe problematic.
Tony Betts or the like I think.

Location: Wessex

David Wilkinson Southern Sevens has a good selection of ends. Best to call in as identifying the correct side can be hard to explain when they are off of the arm. Only know because I needed one

Location: Oakley , hants