Bob Engelhardt wrote:
Winston wrote:
...

1) It did occur to me that the line between the center of your
hinge and the gap between the clamping leaf and bending leaf
appears off - center a bit, which would cause the workpiece
to be lifted unnecessarily.

Good catch. I went to great effort to make the hinge axis on the bend
line, but didn't get it quite right.

Nevertheless, the clamp resists lifting well enough and fails when the
bending force starts pushing horizontally more (after 45 degrees).

I can envision that, now that you mention it,
given the axial discrepancy.

See how Dave used a *piano* hinge? Kewl!
http://www.ch601.org/tools/bendbrake/brakeplans.pdf

That is a nice solution for his problem, but not very extensible. First,
a piano hinge is WAY too weak for any non-trivial bending.

One could always stack regular door hinges side by side, too.
*That* is extensible! *And there is prior art*.

Also, it puts
the hinge axis below the bend line, which might not be too bad - I'll
have to think about it. That would leave the ends open, like the
MagnaBend does.

Interesting, wot? Boring to look at, but very effective.

2) Can you use a permanent magnet to be sure your MOTEs are
indeed out-of phase magnetically? (With your head *out*
of the path of the magnet, preferably!)

Yep, but I want them to be in-phase, to avoid the magnetic shorting that
later posts point out.

Experiment time!

Take two button magnets and place them flat on a table.
bring them together *edge on* so that they are 180 degrees
out of phase magnetically. (That is, flip one over if they do
not attract each other initially). You now have two button
magnets snapped together side - by - side and they are
magnetically 'shorted out' right? North to South and South
to North. Bring a piece of steel down on the magnets
axially. What happens? If their fields are really 'shorted
out' then nothing happens, right?

It's not as if both magnets fly up to the steel or anything.



Now repeat the experiment with the magnets *in phase*.

(When I do this, only *one* magnet flies up to the steel
and the other magnet is *repelled* by the combination!)

'Like' poles repel. Opposites attract.

3) As practice for the next design, would you consider removing
both of your windings, welding both your cores together and
providing a rectangular winding that encloses both center
legs?

Well then I'd have to wind a coil. I'd really rather avoid that.

It is a lot less time and bother than you imagine.
I envision a jig cut from scrap lumber using a scrap 1/2"
machine bolt as an axle. A plywood base aligns the
axis of your 'winding crank' with your spool of magnet
wire. A few hundred turns goes more quickly than you
might think. A lot of inspirational work is
available on Youtube.

--Winston