Gentlemen:
In screw construction the problem is not drawing or laying out the flights of the screw but actually find the correct inside and outside diameters for the disks that you are going to cut, then twist a little so that you can weld them one to the next to achive a continuos strip and then streching them.
You will have to get a tight fit to your center tube and the right outside diameter, this while having the usual "step" equal to one diameter for every 360º turn, you will find that one disk once streched accounts for less than 360º of a flight.
The flights once streched will have a thinner section on the edge than the original plate thickess due to heavy metal flow on the outer edge and that varies with the relationship between inner initial hole and outside diameter, I have found that the smaller the center hole (smaller cenetr tube) for the same outside final diameter the higher flow of material and consecuently bigger thinning of the steel plate.
The big manufacturers even offer you two different ways of manufacturing the screws one as described and the other keeping a thicker section on the outside by using laminating techniques only possible in mass production plants.
Cheers
SACEM1