1. Of the 3 rollers, only the middle one needs to fit the stock, right?
The outer two are just pushing and no bending is taking place there.
Except when bending angle iron with the leg out, or when bending flat
stock the hard way, the outer rollers hold the stock "upright".

2. Grant (I think) posted recently about bending tubing quick-and-easy
by bending around a cylinder whose thickness was equal to the tubing
diameter and sandwiched between 2 flat pieces. I.e., the cross section
of the die was as wide as the tubing, but was square & didn't fit the
tubing at all points (just at 3 points). He reported that this did a
fine job bending and that the tubing was not distorted.

Could this style die be used on large scale benders such as Ernie, Don
(?), and ed_h have built? Such a die would *so* much easier to make,
not having to turn semicircular profiles. Also, dies could be built up
by stacking different thicknesses. I suppose the answer is that if it
would work, somebody would would be doing it, so it must not work. What
do you think?

Bob