JB Weld is not widely available over here, but Chemical Metal is the same. Also Araldite would be fine.
Drilling and tapping is possibly a good idea but cutting threads in poor metal might weaken it further, but if this route IS recommended by an expert it is probably best to use Ferret Sh*t cutting compound like Trefolex or Temaxol to ease the cutting, and take it easy. Happy to send you a spoonful if wanted.