I have an industrial plater who does a super job, regardless of the material. I've had him polish and rechrome several forks and my primary objection is that there was not enough attention to detail where it was most needed--around the lug margins and other tight locations--that I suspect was more driven by the tools and methods used to polish on that scale than by poor workmanship. Everything I get back from them, included a full frame and fork that was nickel-plated immediately goes into my old clawfoot tub for a soak in a baking soda solution and cleaning of bleed holes. I now take my polishing needs to a local guy who is more focused and equipped on turn out finely-polished work. As for threads, I provided a pair of sacrificial cups for the bb shell and an M10 bolt for the derailleur hanger. After plating there was no need to chase any of the smaller threads for bottle holder braze on, fender eyelets or rear dropout adjuster threads. I think your lbs would have real difficulty trying to chase chromed threads anyhow.