[TheForge] Re: helical railing calculations

[Andy Vida]

Ries Niemi said:

> > But one thing I think you theoriticians are getting away from is the
> > way real tools work in a real shop.

	Actually, Bruce is a pretty practical guy, but as far as I
	can tell he likes to have the theorectical basis worked out
	as well.  It's a sickness with him, trust me on this.

> > 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.

	Mongo th ebender would be able to do this without a problem.
	If you know how many turns to make, it's a piece of cake.

	As for twisting it, the problem that will arise is the undoing
	of some portion of the twist as the material is curved, so you
	would have to experiement a bit with over-twisting it, then
	curving and checking to see if you need to twist more or less
	than you have.  A twist will always attempt to undo itself
	when the twisted material is turned into a curve.

	Curving the twist, especially cold, would be a pretty serious
	undertaking, I think.  I'm sure it culd be made trivial with
	sufficiently sophisticated CNC equipment, but why would anyone
	bother?