True Radius Calculation for a spiral
True Radius Calculation for a spiral
(OP)
How do you determine the true radius of a spiral staircase hand rail in order to form the handrail?
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True Radius Calculation for a spiral
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RE: True Radius Calculation for a spiral
If your staircase turns, say, 270° you need to calculate the length of handrail first. This will be the hypotenuse of a right triangle which has:
run=2*pi*(handrail centerline radius)*270°/360°
set=height from landing to landing or floor to floor
handrail length = square root(run^2+set^2)
(allow a couple of feet extra at each end)
Roll the pipe at:
true radius=(handrail length*360°)/(2*pi*270°)
(use the length calculated above not your total length)
After rolling to true radius (which with the extra added on will be somewhat more than 270°) you need to put a comealong on one end and clamp opposite end and pull vertically until you get the landing-to-landing height. Don't include the extra when measuring this height. Try to position your comealong and clamp so that you pull at the 270° position when viewed from above.
Try it with a piece of wire first at a smaller scale.
Let me know if you don't follow this.
RE: True Radius Calculation for a spiral