No one has a reply to my latest attempt?

Hi Todd,
I've been working on a pictorial answer for you ... I will post when it's done.

Todd, with only a shrinker/stretcher available, doing two "L"s and welding together is about the only way I know of to end up with a "U" channel. That is how I will probably make the weatherstrip channel on my roadster. I could do a U channel on the Pmax or Eckold but getting the shape perfect in 3 dimensions would be a real exercise in frustration.

Todd
Have you tried what I suggested??
Peter

Working Curved Channel
 

Hi W.C.
Here is one simple method of working curved channel, that is close to what you are doling, with tools you likely have ..... :

1) Make half-channel flanged pieces:
Attachment 44190
2) Select your cross pein hammer for stretching the short leg:
Attachment 44191
3) Hammer the edge of the short leg, holding it firmly against a stout steel block for back up and hitting so hard the hammer rings against the block - but the part does not move. Hitting accurately is essential.
Attachment 44192
4) Curve your piece to match the inside radius of your corner - length of part is two fingers longer than needed, for fitting and trimming.
Attachment 44193
5) Shrink the other flange to match curve and length. Some repeat stretching with the hammer is sometimes needed for the best fit.
Attachment 44194

In many cases the channel is made and arched for the lengths of each side of the opening, with ends left long. After forming the arches the ends are snipped into flanges - leaving the inside wall and leg - and curved around into one corner. That section is held in place while the cross piece is arched, and one end is snipped to match the previous, with the outside wall and leg. And so forth around the opening. When done, the car shows neat clean work with a couple of weld seams in the corners of the drip channels.

Another method is to form the channels to make it around half of the opening, measuring around the outside of the channel. Form the arch like before, but cut out the entire inside "L" or flange for the full corner, and then make the two ends half-arch to the car Centerline. Make the opposie side, fit both and trim, and weld the two Centerline joints, front and rear.

Now, go back and make the four missing "L" corner sections, stretching the legs to fit and welding two butts and one corner joint at each corner.
Done.

Handmade cars like these, below, had their hood and rear lid channels made using these methods:
Attachment 44195Attachment 44196Attachment 44197Attachment 44198Attachment 44199Attachment 44200Attachment 44201Attachment 44202
Hope this helps you solve your curved channel forming problem,

Perhaps you should try Peters approach at this time as it seems like a reasonable way to attack the problem.
It helps for me to see pictures or diagrams of a process this complex done by hand work.
Maybe if you ask nice Peter would elaborate a little more as I would like to see it formed all in one piece by hand methods.
That's a pretty daunting piece to tackle by hand work for anyone I would think.

aka "form block" in aviation - after WW2 with car industry starting up again, and with labor migrating from war factory to auto, the technique became "hammer forming" which is different from "Wheel forming" I suppose...

Many ways to skin the same old catfish.

If I could draw on the computer I would show how it's done , BUT....I would not know how to even start:eek:
the only thing I can suggest ....
I have cameras in my shop.... no audio (not just yet) but I could try to record the way to do it... and then with a bit of help from my son I could copy it on to a USB stick and send it to who ever is interested:D
Peter

Not sure that the original poster has an English Wheel.

Whether or not he does, the way Peter uses a wheel is not like the videos and demos I have seen. after watching Peter manhandle his wheels at RockHillWill's shop last fall, all I can compare it to is how people are supposed to use a screwdriver and how every one of us really uses a screwdriver. Most use an English wheel passively. Peter pumps, twists, lifts one side of the metal while pushing down on the other- whatever it takes. At times, it looked like he was going to flip the wheel over when he was making the metal do what he wanted it to do. I'm not kidding. It wasn't the calm back & forth while holding your mouth funny like most pics show....

Think about how you put something in a vise, then twist and pull and push against it to bend it, often to the limit of how the bench is attached to the floor or wall. The same thing happens in the wheel. The difference is that when done in the wheel the metal is rolling back & forth instead of staying in one place.

By cocking the flat/square lower wheel so it isn't parallel to the upper wheel, you can use the chosen higher edge of the lower wheel (which is now all that is part of the lower wheel-metal-upper wheel contact group) to create the desired line in the metal. Move slowly to follow your desired line while pulling down or pushing up as needed. It works very well and is not difficult. Peter's English wheels have a screw on each side of the lower wheel saddle to make such adjustment simple. But you could easily shim an axle end on a non-adjustable saddle to achieve the same thing. I ordered my flat lower wheel/anvil from Hoosier with different radii on each edge for exactly these reasons. No bead roller here yet.

Whether or not you have an English Wheel, like Kent said, there are many ways to achieve the same result.