[frogvalley]

Ok more questions for you. Are you talking about a stand alone spiral staircase that goes straight up a pole? Or are talking about a railing for an existing staircase?

If you are talking about creating a spiral one on a pole thats actually fairly easy. It is designed the same way that a regular set of risers and treads is done for a a straight staircase. Height (10 feet) divided by the height of each riser- say 7 inches. 17 steps roughly. If you add a platform or landing at top , one less. I am looking at my own staircase and can see how easy it really is , only I am not the best teacher. It goes up eight feet and has twelve steps and landing at top. Each step is 12 wide at the outer edge.

You could adapt or modify a commercial set, but it ain't that hard to do the math. I'll try to write a more coherent description of the design I would use. I have had to do trigonometry three times this week on blacksmith projects and my brain still hurts from it.