firehawk

Hi, I'm from Germany. First I have to say that my English isn't the best. Ok, I own a demilitarized (non working) World War 2 Thompson, model M1A1 built in 1943. Now after a change in the law (relating weapons) I want to rebuild it to a semi automatic one. I started with the reproduction of the barrel. But I have one Problem. The screw thread at the rear end of the barrel which is used to mount the barrel in the upper receiver isn't known in Germany. Ok, I know it's not a metric one, it's an inch one. Please can anyone of you give me the correct measurements and labeling/marking of that thread? Thanks!!!!!