Circular stairway handrail roll radius
Circular stairway handrail roll radius
(OP)
How do I calculate the radius to roll the railing for a circular stairway? I know the plan radius and stairway angle. I know this is simple but it eludes me!






RE: Circular stairway handrail roll radius
The actual handrail shape is a helix. Rolling a handrail to a circular arc only approximates the shape. The handrail has to be twisted slightly as it is installed, after rolling.
The formula above is derived by taking a very short section of handrail, finding the deviation from a straight line, and then solving for the radius that will give that deviation with the actual sloped length as the arc, with small-angle approximations applied as needed.