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-   -   E-Wheeling Shelby Cobra Bonnet (https://www.allmetalshaping.com/showthread.php?t=11762)

longyard 06-17-2014 11:36 PM

E-Wheeling Shelby Cobra Bonnet
 
Hi all. I hope to be posting a few more "how to" videos the next week or so. Here's the first. Mark Gerisch rolls a Cobra bonnet in less than an hour. The video is just over 20 minutes.

https://www.youtube.com/watch?v=CZEv...ature=youtu.be

Phil Minton 06-18-2014 01:29 AM

Thanks for posting that Bill, I enjoyed watching it and particularly liked the 'picture frame' analogy and blending in the edges once the shape is formed.

ekdave1962 06-18-2014 03:44 AM

very interesting .. i notice it took the student a little time to get his foot work right if you noticed he was walking in small steps but toward the end he got the hang of the rocking method ..

Jerry Jackson 06-18-2014 07:06 AM

A great video! What is the purpose of 'pinching' the sides together (pumping?).

Jerry

San Antonio

toreadorxlt 06-18-2014 08:47 AM

Noobie questions maybe somebody can help me with:

Why is he very particular about how his partner holds the panel? Wouldn't the same shape be induced either way? Is he trying to get his partner to induce a closer to final arrangement while adding shape?

I typically wheel alone, and the other end slips on larger panels, but it seems like my shape doesn't suffer, only arrangement.

Jere 06-18-2014 10:12 AM

Nice video Bill.

I was hoping others would get in on the tutorials thread. :D

Jere

MP&C 06-18-2014 10:15 AM

Quote:

Originally Posted by Jerry Jackson (Post 98401)
A great video! What is the purpose of 'pinching' the sides together (pumping?).

Jerry

San Antonio

Quote:

Originally Posted by toreadorxlt (Post 98402)
Noobie questions maybe somebody can help me with:

Why is he very particular about how his partner holds the panel? Wouldn't the same shape be induced either way? Is he trying to get his partner to induce a closer to final arrangement while adding shape?

I typically wheel alone, and the other end slips on larger panels, but it seems like my shape doesn't suffer, only arrangement.




If one were to planish a spot on a sheet of metal using a hammer on top and dolly beneath, this may add some stretch but things don't change all that quickly as the metal has not be persuaded very well in which direction to go.

Now take a sheet of metal on a shot bag and strike it with a blocking hammer. This has given the panel a bit of stretch, but also given it direction.


RE: the helper holding the panel in tighter at the front of the panel, the hood has more crown across the front edge than the back edge, so it is being given more persuasion.

Richard K 06-18-2014 10:38 AM

An interesting video to watch, but not very instructional. There were a number of techniques mentioned such as holding the sides of the panel together that had a very sketchy explanation attached. It would be nice to hear a bit more about certain parts of the operation. I watched Marks power hammer videos and the explanations were also lacking there. Maybe it was different in person.

For instance "the picture frame" was not mentioned until Bill asked about the waviness on the edge. But did the waviness go away? It would have been helpful to see that happen as they were wheeling on that side. Or some other mention of it. There was a bit of concern over the fore and aft curvature but the curvature across the panel was not ever talked about. How was that executed? It maybe was not planned to be a part of the video but certainly is about half of the project requirements.

What I'm trying to say is if one wanted to make a hood and just followed the video, I think you would not be successful.

Hopefully this is taken as constructive criticism. My intention is to say what I, and possibly others, would like to see in a how to video. In the videos Bill showed from the English guy, procedures were explained and then the results of that process were pointed out. those were very helpful.

toreadorxlt 06-18-2014 10:44 AM

Quote:

Originally Posted by MP&C (Post 98405)
If one were to planish a spot on a sheet of metal using a hammer on top and dolly beneath, this may add some stretch but things don't change all that quickly as the metal has not be persuaded very well in which direction to go.

Now take a sheet of metal on a shot bag and strike it with a blocking hammer. This has given the panel a bit of stretch, but also given it direction.


RE: the helper holding the panel in tighter at the front of the panel, the hood has more crown across the front edge than the back edge, so it is being given more persuasion.

Just so I'm clear:

So by inducing direction in a wheel (physically manipulating the sheet by pulling,lifting, twisting,pinching) you are saying I can achieve shape change faster? I imagine a secondary function of this would be getting the panel closer to its final arrangement as well.

Janne 06-18-2014 10:58 AM

Steve,

When you have adjusted pressure on your wheel.It is that certain pressure you just adjusted.When you take a hold of the your panels edges, and press the edges towards floor...you increase the pressure on contact point, cause you get a leverage of the sheet..as you wheel..Think what happens when you put a plastic wrap on top of a ball shape object, and pull the plastic wrap down, the ball wants to come through the plastic wrap..on metal it canīt do that, but the sheet stretches more..via the more pressure applied...

And yes more pressure, faster stretching and faster shape...

This is how I see it...someone can correct, if I am thinking this wrong..


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