I know that one can bend plate in a slip roll or with a press brake. But how can one put a twist in plate, like taking a strip of plate and twisting it such that the bottom becomes the top? Is that just a matter of putting a bend at an odd angle? But how can I get a very different radius at each end of the bend? With sheet metal, it is pretty easy with hand tools and jigs.
I confess that I have never even seen a press brake, and have limited experience with slip rollers.
If you want to know why I want to know, or a picture of the application, click this link:
The author mentions "stakes," which is a general name for a wide range of sheet-metal forming tools. A steel stake that fits into the hardy-hole of an anvil, or into the jaws of a heavy-duty vise, is made in different forms for bending and hammering the metal to shape. For example, a shape that's a part of a cone, triangle-shaped, is used for hand-forming metal cones.
I've made a lot of Mobius strips from paper, and a couple from aluminum flashing, so I can tell you that the problem is keeping the twist from kinking. The problem is vastly more difficult if the original strip's width-to-length ratio is fairly high, as in the sculpture examples in your link. Notice the author's aluminum example, which has a bit of a kink in it. A cone stake would let you beat some of that kink out, working gently with a rawhide or rubber mallet.
The copper and aluminum he used is fairly thin, which is easy to form. If you haven't made any Mobius strips before, buy a small roll of 6-in.-wide aluminum flashing at a hardware store and give it a try. As for making an invisible joint on the ends, that's another problem, but you'll get plenty of tips here. Do you weld or braze?
By "plate" I assume you mean heavy stuff, 1/4" thick or more. That's going to be a problem. I don't know of any tools that are made for machine-forming a Mobius strip.
Here is an overly simplistic answer. If you can cut, fold, curl or modify a piece of paper to look like what you are after, it can be done in metal. Look at and analyze exactly what it is that you do to the piece of paper to get what you are after, you will need to exercise the exact forces to the metal. The difference will be that it may take more than just your fingers, a scissors, and a roll of scotch tape to accomplish the task. Metal will actually do more things than paper, it can be made into bulges and depressions that are not possible to accomplish with the piece of paper due to metal's ability to shrink and stretch.
The sculpture piece you reference did not use a break of any type. It may have used a shear and may have used a roller, but was probably done with hand snips and hand pressure, solder, and a lot of sand paper.
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Is that your site you referenced? Or just a coincidence that you have the same name? If it is your site, why are you asking how to do what you have already done???
I don't think either are what you need for this job. There's several ways to go about it but a combination of a few of them would probably work best.
One a large press similar to the one I have (look on my home page below, misc pics page, second from the bottom). Two is some form of tie down on the floor of the shop and a hoist, winches, tie points around the piece, etc. Some means of putting serious pull in different directions. Some work with a good adjustable pinch roller would help start the piece but there will be a limit to how much can be done with that. Another method is heat and cool which will put a bend in the heaviest plate. It's slow going but that's one of the methods they use to get those compound curves in heavy plate used on ships.
As for using the press to make a twist. Well you put your supports at a angle to the piece and place your pressing block between them. I do this all the time but it's usually the other way around (I'm straightening a twisted piece). The tying to the floor is done in a lot of shops in fact they make a floor platen just for jobs like that. Google Acorn platen or table to get a idea.
Of course it does make a difference on how heavy you're wanting to go. When I think plate I usually think of something like 1/2", 1" or the like. Both would be rather difficult to get in that form but definitely doable with enough time and effort put into it.
It is doable with a press brake on quarter inch or even heavier. Of course you would not be able to make the complete strip in one piece. I would guess the revolution might take four pieces, maybe three depending on radius, width of strip and clearance on the press brake. To create the layout you will have to do a series of triangles to get the development. Look up in a sheet metal layout or good drafting text. Some developments are parallel line, radial lines and the last method is triangles Once cut the forming will be a series of hits not parallel to each other. The tighter bend area will have hit lines closer to each other compared to the large radius areas. It is not unlike forming spiral shapes. Randy
I confess that I have never even seen a press brake, and have limited experience with slip rollers.
If you want to know why I want to know, or a picture of the application, click this link:
What you suggest is more or less how I envisioned making a Mobius out of
1/4 or 3/8 inch plate. I was thinking of makeing a full size model out of sheet metal, and then using the model as a template to guide the press brake work on the plate.
Besides the issue of finding a shop willing to try something strange on a time and materials basis, there are all the learning curve issues. I might be well advised to build a medium size Mobius out of 1/8 inch sheet before stepping up to something heavier. Getting it all to fit together right would also be a challenge. Probably would need a porta-power or other way to exert major forces to get things aligned right for welding. And how do I get the joints to have a consistent curve if I can't use a hammer to make adjustments?
Looks like a challenge. It is something that I have been thinking about for a while.
If you are making a full size model it can be made of cardboard if you like.. If the operator has sweeps for each radiused section it is easier. A sweep is simply a crescent shaped template about a foot long that can be put up against the plate as the operator is bending it. A sweep for each edge of the curve would be needed, If the forming is perfect then you will not need a porta-power. Actually for 1/4 and 3/8 plate a couple of chain com-a-longs, dogs and lots of steel wedges will do the trick. The welding to connect sections will have to be done carefully or else the weld seam will increase or decrease the curvature giving a kink in your nice curve. Making a quarter size or smaller scale unit out of 1/8th plate might be economical. Randy
1/4 or 3/8 inch plate. I was thinking of makeing a full size model out of sheet metal, and then using the model as a template to guide the press brake work on the plate.
Besides the issue of finding a shop willing to try something strange on a time and materials basis, there are all the learning curve issues. I might be well advised to build a medium size Mobius out of 1/8 inch sheet before stepping up to something heavier. Getting it all to fit together right would also be a challenge. Probably would need a porta-power or other way to exert major forces to get things aligned right for welding. And how do I get the joints to have a consistent curve if I can't use a hammer to make adjustments?
Looks like a challenge. It is something that I have been thinking about for a while.
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