Basically have some detailed drawings before you go to the machine shop. Hand drawn blue prints will work if they are legible and coherent. CAD software will greatly aid you in the whole process if you have the access/know-how.
Imagine taking this drawing to an contractor. Sure you've got some ideas down, but they aren't going to even think about making it with out specifics. This means dimensions, tolerances, thread sizes and all that fun stuff.
Good luck.

Imagine taking this drawing to an contractor. Sure you've got some ideas down, but they aren't going to even think about making it with out specifics. This means dimensions, tolerances, thread sizes and all that fun stuff.
Good luck.