[TheForge] Re: helical railing calculations

[Bruce Freeman]

Ries,

I can see rolling a flat bar "the easy way" (i.e., deforming the short
side) to a small diameter, but why would you ROLL a handrail "the hard
way"?  Is that even possible?  I'm envisioning putting a, say, 2"x1/2"
bar in a slip roll "standing on edge."  Sounds difficult to me.

Are we communicating here?

I would have presumed such a bend would be done hot around a mandrel
(or around several posts in an acorn table, together acting as a
mandrel).

Bruce
NJ 

>>> rniemi at fidalgo.net 9/23/2004 11:22:33 AM >>>

Usually, I am a "get out the 24" crescent wrench and the cheater bar" 
kind of guy. As opposed to the integral equation kind of guy.
So I just yank on it till it looks right, then add enough decorative 
details to distract the eye.

But one thing I think you theoriticians are getting away from is the 
way real tools work in a real shop.
And I cannot think of anyway to either "pretwist" a bar to a specific 
pretwist, or to roll a curve in a bar that has been pretwisted. My 
rolls will easily bend that flat bar the hard way, but in doing so, 
they will remove any pretwist I had somehow managed to put in. And 
since short of building a twisting machine as big as my whole shop, I 
can imagine how that pretwist got in there in the first place.

Otherwise, keep going. I  am reading it, even if I am not fully 
comprehending it all.

ries

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