Hello everyone, quite a while back I posted a classroom aide that was modeled to help explain spiral staircases and some of their lay-out issues and methods. At that time someone asked me about the handrail; well I finally did something about the handrail, but not before I did some "heavy" research(for me), to determine the formula for determining the starting size for the handrail helix. I had a home-brew type of formula that would get close but it still wasn't quite right, after checking on the internet some I found a couple of sources for much better information and what follows is a first attempt at providing an applicable method. The "pitch" that is referenced in the formula is the height of one 360 degree turn of the rail and the "inside radius" that is referred to in the formula is the number that is representative of the finished inside radius of the rail. The "Answer" that is arrived at by dividing "Product 1" by "Product 2" is the inside radius used to layout the rail section in it's flat condition before stretching. I hope this makes sense, if not please help out with any comments for something more user friendly. Best regards, Allan