I have welded several lock boxes into gates, when my clients wanted a way to lock the gate with a deadbolt, or even made
their gates self-latching and self closing and I did them all with my super junky Harbor freight 110vt ac arc welder and some
5/64" welding rods. Of course the quality was not great, but a bit of sanding and some patch work with a bit of body filler,
a little wet sanding and a coat of black primer made them all look well worth the money I was paid.
Now if I were to be called upon to do another I would use my Hobart wire feed welder and would do a better job. Though as far
as I know all the gates I have welded on are still in use.
I just don't want people to think welding a gate box into a gate is rocket science-- measure twice & cut once and take your time
to do it right the first try