I'm not a practicing metal shaper but my long-time friend , John Toom,
had a solution for the problem that is being discussed. He made a "C"
shape of sheet metal that was firmly attached to the lower part of his
wheel and floated on stand-offs around the shape of the wheel until it
got to the area of the upper wheel. Here he put a calibrated plate that
was attached to the main frame and a pointer that was attached to the
"C" shape that was not under stress. When pressure was applied to the
metal being wheeled he could read the amount of deflection in the main
frame and thus the amount of pressure. Of course the more rigid the
frame the harder it would be to measure deflection. I'm thinking that a
dial indicator would be able to very accurately reproduce the same
amount of deflection (pressure) every time. This might make it possible
to repeat a process that would work on consecutive pieces.
Maybe you have already done this and I'm just not following the
discussion well enough.
My $.02, Larry

--- In metalshapers@yahoogroups.com, "Kerry Pinkerton" <pinkertonk@...>
wrote:
>
> I don't know Bob. The problem with what you describe, imo, is that
you're probably not going to be that consistent. When you're making a
panel and go through a stretch/shrink process and find the panel still
needs more smoothing or stretching, you just increase the pressure a
little and wheel a while. If you had a set clearance and a stiff frame,
you've basically got a rolling mill but a set clearance probably won't
give you the finess you want to obtain the shape you're after...
>
> Just my opinion.
>
> Have you considered an upper adjuster. Kickwheels have little
feedback to tell you how much pressure you're applying but the handwheel
and your hand is Gods own torque wrench and I find it very repeatable
and controllable.
>
> Kerry Pinkerton
> ----- Original Message -----
> From: robert lovell
> To: metalshapers@yahoogroups.com
> Sent: Thursday, July 02, 2009 6:02 PM
> Subject: Re: [metalshapers] Re: pre stretching
>
>
>
>
> Yowza All,
>
> Been following this thread and others like it for a while..
>
> Made my last 2 e-wheels and the third one is partially
CAD-ed up. As of late I wa thinking the same thing about repeatability
along with keeping both hands free.
>
> My second unit was a kicker style adjustment that went
through several modifications until I realized something else may be
needed.
>
> Currently debating a gearbox with an indexing motor or some
other way which would allow me to have a "value" assigned to the wheel
used that could be easily repeated fro later use.
>
> Almost wish there was a "standard" that could be utilized
but most likely will set the value to be a function of the number of
threads used or possibly a force gauge would be slipped in to give me a
running reading of what I'm doing.
>
> If anybody has suggestions or caveats don't hesitate to
educate me.
>
> Thanks, Bob
Lovell
> --- On Thu, 7/2/09, John Buchtenkirch jbhammer@... wrote:
>
>
> From: John Buchtenkirch jbhammer@...
> Subject: [metalshapers] Re: pre stretching
> To: metalshapers@yahoogroups.com
> Date: Thursday, July 2, 2009, 7:23 AM
>
>
> I was thinking while I was doing mine. Yeah I know... If a
person were to index his handwheel/kickwheel with some type of
repeatable markers and then kept a good shop notebook of what index for
what bead with what width pre-stretch in what material, it should be a
repeatable process without the trial and error every time. At least I
don't see why that wouldn't work. Something to try if doing a lot of
bead rolling anyway. ~ Kerry Pinkerton
>
>
>
> Kerry, don’t see how that couldn’t work on a
run of parts that had the same bead and same gauge metal. That is the
advantage of doing runs of parts over the one of hero type jobs,
sometimes you can figure out how to produce parts quickly enough to make
some serious $$$. I think if I had to do a large run of beaded parts I
would devise beading tooling for the Pullmax that was surrounded by
pressure pads so the beading would be truly stretched in to eliminate
the pre stretching step all together. Just thinking out loud. ~
John Buchtenkirch
>