You can buy an Uzi barrel that is already threaded for a Mac style suppressor directly from Bushmaster. You can easily get this barrel for under 100.00 which makes it a great deal. You then can keep your orignal Uzi barrel intact and just switch it out when your ready to shoot suppressed.
I hope this helps. If you have your heart set on having the Uzi barrel turned, let me know, I have a smithy that can do that for you.