(This may be more opinion than factual.)
I have a rolling cart my wife uses for hobby supplies. Each leg is a rolled metal tube about 2" in diameter. In each leg, there is a disc of metal tack welded to the sides and a nut has been tacked to each disc so threaded casters can be installed. One of the nuts broke off because it was poorly tacked in only two spots. Unfortunately, I can’t measure the thickness of the metal disc, but it is fairly rigid.
Can I braze the nut back in place? I can get a pencil torch head for my propane cylinder for about $20 and several flux-coated brazing rods for about $5.
I don’t have any welding equipment. Even if I did, I understand that welding to sheet metal can be tricky and require practice. A couple friends suggested hauling it down to a welding shop, but I honestly don’t want the hassle and will probably end up giving the cart away if I can re-attach the caster. I can always use the torch head for other projects.
Mods, feel free to move this to IMHO if appropriate.