#11
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Quote:
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Rocco |
#12
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Right side reverse
I've made some progress and had some setbacks.
I've done some planishing and fine adjustments to the side pieces but the main thing I've been working on is the right side reverse. I'm trying to take cliff's advice and be more deliberate. I made the left reverse by starting at the outside curve and shrinking to the inside curve. I decided for the right side I would start at the inside and shrink to the outside. template.jpgbeginning.jpg I was happy with how the panel cut out. I gave the panel a simple bend to match the left station. The left edge is the same length as the station it fits over, the right edge needed to stretch about two inches to cover the other station. The wheel is the best tool to make this shape, but I don't have one or the funding to make one. Instead, I decided I would just pretend I was the wheel and make a series of even stretching passes over the dolly. I made one pass at the edge, then another an inch away, then back over the first pass, etc. working my way inwards. wheeling1.jpgwheeling2.jpg This was working, but very very slowly. After 2 hours of doing this there wasn't much crown to speak of. I needed a way to stretch faster. I started using the cross pein, and that worked a little better, but it was still very slow. checking.jpg In this picture, the green line is touching the station but the red line sits about an inch away from the bottom. I still had a long way to go. To get the most possible stretch, I made a jig to hold my tightest radius dolly up so I could use it with my cross pein. stretchingjig.jpgstretching.jpg This stretched faster but wherever I stretched crushed the curve flat, so to check against the buck I would have to work it over the rail dolly again to get the curve back. I did this stretching for an hour and got some good crown, but I started to run into an odd problem: I had plenty of surface area but the inital bend I had made had flattened, so that only one part of the panel would touch. I tried messing around with it on the sandbag with a mallet to get the bend back, but eventually I had to face facts: Either I had to stretch the middle of the panel ALOT, or shrink the left flange. I tried stretching first, but it wasn't going anywhere, so shrinking it was. firstshrink.jpg The stump has dried a little, so first I tried shrinking with a tucking notch. After tucking and hammering and tucking again, the panel still wasn't moving where I wanted. At this point I decided I needed to change my broad strategy. I needed a way to guarantee I would arrive at the curve I needed, so I came up with a plan: I copied the curve from the right station onto my template, then made a jig to hold my panel shrink1.jpg Then I used the tucking fork until I got the bend I wanted back shrink2.jpg Then I clamped the panel hard so it couldn't spread out as I hammered down the tucks shrink3.jpg I had some tucks that were threatening to overlap so I had to take the panel out and re-clamp it where I could get at them. It didn't spring when I unclamped it, at this point the panel still had the curve I wanted overlaps.jpg But I must have done something special with those last tucks, because a small miracle happened: miracle.jpg I definitely wouldn't have guessed I'd end up with a flatter curve than I started with but there I was. I tried this process again, but I ran into some new problems: The flange really, really doesn't want to move. It hates moving so much that it bends my tucking fork instead of the fork bending the panel. Why not just anneal it? I finished my new slapper, I blocked the contact surface flat as can be and gave it a great finish, I'm proud of it: newslapper.jpgshiny.jpg But in the middle of heating it up for the joggle I ran out of acetylene, and I can't get more at the moment. So no more torch for awhile. The slapper still works good flat though! I have some ideas for how to proceed, but that's all I have for now.
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Rocco |
#13
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Rocco. Put down the hammer to long distance from you and get the wrapping paper and tape. This is the most important point for understanding. The basic question is where the fibers of the material are heading. Stretch or shorten. You need orientation.
The first two threads show a fender. 1. Arching. When the plate is twisted into a small coil. 2. You grip the scroll by the edges on the other side and place it on the table and spread it out. If you don't have the strength, put it on the ground and step on both feet. 3. You smoth in EW Note: Not a single jaw for download !!!! Mj. similar to the shape you make. In the second thread: Reverse curve in EW. You are rolling the edges with a slight pressure and the sheet is shaped where you need it. No hammer. Even if you little tap the edge properly and avoid the middle, it will work. You can see the paper templates in the pictures. How to use them and why. What the paper shows can be made of sheet metal. !!!! In my other threads are all the procedures including mistakes and thoughts and nerves. It takes time and effort. Exercise makes perfect. And lessons from one's own mistakes and the mistakes of others. I am waiting for your results. https://www.allmetalshaping.com/showthread.php?t=19643 https://www.allmetalshaping.com/showthread.php?t=18968 DSC01607.JPG DSC01608.JPG DSC01609.JPG DSC01611.JPG DSC01612.JPG DSC01619.JPG DSC01617.JPG DSC01336.JPG DSC01385.JPG DSC01344.JPG DSC01345.JPG DSC01346.JPG DSC01386.JPG
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Jaroslav |
#14
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Without an English wheel, another option to consider is an arbor press. Now that youve divided the work into smaller pieces, I think you would like the results. For shapes like a motorcycle fender (whether shrunk/curved along both sides or just one) it's a great method.
Much less clean-up is needed because the arbor press work doesn't wreck the metal as much. They're Super accurate, which helped me learn to do better work with a regular swung hammer. You can make your own tooling. Tonnage isn't as important as throat for clearance . Before I got my English wheel, I had my arbor press. I still use it to shrink edges whenever feasible because it doesn't damage the metal like a regular Lancaster does or typical tuck&hammer work can. If you can find one that fits your budget, it's worth considering.
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AC Button II http://CarolinaSculptureStudio.com https://www.youtube.com/channel/UCzSYaYdis55gE-vqifzjA6A Carolina Sculpture Studio Channel |
#15
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If I am viewing your tuck shrinks correctly it looks like your hammering them down by working (hammering) from the edge inward. That is backwards.
Doing them that way will always leave a bit of extra metal (a little bulge) where the far end of the tuck was. You want to hammer from the farthest point out towards the edge. You will get a better shrink with no bulge at the far end of the tuck. https://youtu.be/qBG4XNzDKs8 Go to the youtube link and watch it. It is less than a minute long. But notice how he locks the far end of the tuck in by changing the "Y" shape at the far end of the tuck to an "I" shape. Then he hammer out towards the edge.
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Dave Bradbury Last edited by blue62; 04-22-2022 at 03:54 PM. |
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