I was recently approached by a customer who happens to be a market gardener, who wanted me to manufacture him a strange new design of plant climbing stands. Essencialy what he wants is a large spring, 4 FT high with a bottom diameter of 10 in and a top diameter of 18 in with the body composed of 7 coils and made out of 5/16 ss rod. And since the customer wanted quite a few of these i fiugured the best way to go about it was to build some kind of machine to roll the above-mentioned coils. But when i started on the design i dicovered that i really had no clue on how to start and so i humbly request that those among you reading this with more experiance and inteligence then me to please contact me with any tips or ideas you would be willing to share with me
We used to make coiled titanium tubing for a heat exchanger. The process which worked well was to create a mandrel which was mounted in an engine lathe. The tubing was inserted, braced, then the lathe was spun at a very low RPM.
The process allowed for very repeatable results.
5/16 SS rod will bend a lot easier than 1/2 Ti tubing, so you should be able to use a less powerful device to spin the mandrel. The mandrel will be rather important for getting the diameters, and coil spacing right.
Be careful winding the stock, if it snaps back for any reason, it will a serious injury.
I would not suggest a hand cranked approach, but check out this link on making jump rings for chainmail armor: http://www.artofchainmail.com/patterns/windingandcutting.html
The images should give you a good idea on how the mandrel will work to form the rod.