Any good metal fabricators should help out with threading!
Just take your barrel along and state it's not a firearm, I have a good one that I know next to my workplace and they've fettled an awful lot for me over the past couple of years.
They have a young Polish chap working for them who is handy as he used to make firearms back in Poland. So really knows what he's doing and only charges me a tenner.
Failing that any gunsmith in the yellow pages is the next best thing!! Might cost more tho!
Cheers Mark
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