Trying to keep it a bit simpler than Snowy, maybe, and I don't want a broken bit in the Kimberly or Simpson later this year, so some 5 mm and 3 mm plate, and someone who knows 6061 ally and TIG, and voila:
The bearings were removed, and the plates were fitted over the existing welds. The arm was held in a jig while it was done. No material was removed. Notice how little heat was used, the only clear coat removed was done mechanically, none burnt.