[Jason Kixmiller]

As for turning down one end, most lathes have a chuck that will allow the material to be passed through the entire machine. If the lathe you hope to use has the capability to handle the diameter you are using, this is probably the easiest method. Be very careful with the extra tubing that is spinning outside the lathe...it can be easy to forget but will remind you that it's there very quickly! For the slot, I would use a V-Block set-up in a standard vise to hold the pipe on its sides allowing you to run an endmill through one side of the tube.