Hi, I'm trying to create a flattened part from a tube that has been spiral cut.  I'm not sure if I should start with the tube and work towards a flattened part, or start with a flattened part and work towards the tube.  My finished tube is 12" OD X .125" wall X 12" OAL.  I need two revolutions w/ a 6" pitch.  I'd like to have the flattend part water cut for subsequently conversion into the tube shape.  Any ideas would be greatly appreciated.

Thanks