[morzh]

Well, if you use a nylon bolt of a large diameter (and I am sure you can find one in black) you could use it as the insulator.
Now, you could simply drill a hole through that nylon bolt and insert a metal smaller bolt (the one that is the terminal), and then when all is assembled, simply glue the plastic bolt inside the copper tube.

I am sure given the proper instruments that can be done.

Then there is that groove at the bottom that a pipe needs to look a bit more authentic but that can be simply turned. And if it is deep inside the chassis - simply disregarded.

The top though has nothing special about it - it does simply look like a pipe and a cap.

Someone should try it.