Cracks in Spider gear bearing tube

[Viv James TraX Interconnect (Pty.) Ltd]

I just stripped a rusty rear axle that I found lying behind a shed
after 30 years. Inside, I found a really nice crown wheel and pinion.
I want to use the centre unit in my latest restoration but there are
fine cracks in the threaded bearing mounts on the spider gear
housings. The cracks run inwards across the threads and are worst
in the cut-out that that the nut clamping washer fits into. I can't be
the first one to find this problem. Is there a neat fix?

Viv James