Umarex machine shop for notos

I'm looking for a machine shop that will shorten a umarex notos air tube..or mak a shorter air tube..
I normally do all my own machining but my lathe won't do metric threading..
thank you for any help or recommendations.
Mark
I'm wanting a compact pistol..I can shorten the shroud and barrel myself, just need the air tube shortened or a place to buy a short air tube
Mark