Don't own a bead roller. Hard headed enough to try this. Started with a 3/4 plywood base. Added 3/8 strips to outline ribs. Added sheet metal and more wood strips to hold everything together. Then the fun began, tried all kinds of tools and shapes, by hand and pneumatic, failure after failure. Finnally found the dome shape on the end of a 3/4 in round stock would work by hand. Also found that 3/8 depth of rib was not working. Added strips of thin plywood into the rib moulds. Got several hours in that first rib with the shrinking spots in it. Way too long. Welded the domeed tool onto a shank to fit my air hammer. Added a air regulator too. Now we're talking, about 7 minutes each on the other ribs. Tool broke twice, not sure what to do about that. Turned the whole thing over on concrete floor and did some hammering, stood on it and bent it untill it got pretty flat.,even used the air hammer again with a flat bit around the edge of the ribs. Not perfect but good enough for my trunk floor in my 56 Fairlane. I'm qute proud. If anyone has any tips that would make this better or faster I'm all ears! Thanks for looking!
I can't add much except if you want a sharper and straight bend line....you need to run the top wood piece right on the bend line. In other words the top wood needs to be directly above the edge of your wood strip edge under the metal. One thing I just thought of. I did make pressed beads once on side aprons on a 1920 Republic truck. I made something very close to your lower form, but I laid a solid long shaft on top of the new sheetmetal, then I used a hydraulic jack to push down on the shaft every foot or so. I set this up under a crawler tractor that had a big counterweight on the back. I used the jack under that.
I'll add a little to this, since you don't seem to mind if I hijack your thread. I have a bead roller, but I really dislike using it because of all the distortion it causes. I tried this method and you still get some distortion, but on the floor pan pictured, there was zero distortion after I hammer and dollied the edges of the seams. Turned out nice and flat, with no oil canning. I have tried to hammer and dolly bead rolled dies also, but they never seem to come out 100%. I used CAD design (cardboard aided) to make the shape of the floor pan, then drew the beads out that I wanted to put into it. Cut it all out as shown. Once the basic pattern was established, it was transferred to the 18 gauge cold rolled sheet metal. Cut out the bead areas as shown. Its important to draw the shape of the beads onto the sheet metal blank cause the cardboard needs to be slipped under the sheet metal so you can draw the beads out on the other side of the sheet metal also. I took a centre punch, and very lightly marked all four corners of the cardboard pattern with a light tap of the hammer. After that, take the cardboard and slip it under the sheet metal. Then flip the whole works over, and line up the cardboard with the 4 centre punched marks. Now, the cardboard is in exactly the same place as it was on the other side of the sheet metal blank. Draw the whole design onto this side of the sheet metal blank as well. I used a sharpie, and of course you need to clean the metal so you're not trying to draw sharpie lines on an oily surface. But I didn't have to tell you that, eh? Now the sheet metal blank has sharpie marked patterns on both sides. Take the 3/16 thick steel "bead shape" and put some two sided tape on it, then stick it to the surface of the sheet metal exactly where the bead needs to be, as you can easily see that with the sharpie design. Carefully flip the whole shebang over, being careful to not dislodge the two sided taped 3/16 thick steel piece. It stayed in place no problem for me for the purpose of this exercise, but if you throw it around, it might just fall off. Use good two sided tape. I clamped the sheet metal blank to my work table, which isn't fancy. Its a 1 1/2 inch thick table top, with kitchen counter top arborite. I really like this surface for hammering, as it is somewhat resilient. Feels better than hammering on a steel table. From the pile of tools, pick a brick chisel that has had all the sharp edges eased off with a belt sander. You don't want any sharp edges on the tools, as they will transfer uglies onto your work. I use these brick chisels for a lot of stuff, and shape the ends of them, as well as steel chisels like the one shown in the pics. I have two drawers full of odd shaped chisels and railroad spikes, etc. that have various shapes ground onto the ends of them. Because you have the outline of the bead on the top side of the metal blank, you can place the brick chisel maybe 3/16 of an inch away from the straight sharpie line. Use the BFH and give it one quick blow, and you will instantly see where the edge is on the piece of 3/16 steel bead below. Then hit the other side. That should trap the 3/16 steel piece below, even if the two sided tape were to pop off. Continue around the circumference of the bead one hammer blow at a time, and you will have a beautiful bead in just a couple minutes. I use the small steel chisel with the squared end to go around the ends of the bead with many small blows, shaping it as we go. Once the bead has been established, use a hammer and dolly to clean up any imperfections.
I got some duplicate pics? I felt this might not be clear enough, so I went out to the shop and made a small piece, and took some pics of the tools so the tale can be told with a little more clarity. The first pic of the sheet metal clamped down has had 4 hammer blows with the brick chisel. The next pics that show the one corner shaped with the small chisel was another 10 small hammer blows. Once you get to this point, the sheet metal blank has to be clamped down so it won't move around on you. Once there, it only takes a couple minutes to finish the bead. This little triangular piece took me maybe 5 minutes, start to finish. (I already had the triangle blank) It takes a few more minutes to planish out the edges of the beads to eliminate the distortion. I like this method better than using a bead roller. It also works on 16 gauge material. I made the inside rear corners for my 57 Ranchero box from 16 gauge and they turned out pretty good also. It just makes the metal shaping more like blacksmithing in that you have to swing the BFH a little harder. I should add that the little triangular piece isn't totally symmetrical but I only spent a couple minutes on it. A little more time and it could be made to look a lot nicer.
Just for the hell of it, here are some pics of the Ranchero inner rear corners. These are hammered out of 16 gauge cold rolled. Same shit different project, and was a little harder to do as I had to keep moving it and turning it to pound the shape into it, because of the corner curve.
THANK YOU SO MUCH!! I read your first post twice as I was having a bit of trouble following, but you cleared that up! I searched the internet for this type info and came up short. This is the opposite of mine but I will give it a try for sure. Thanks for taking the time!
For a good source of large pattern material, I go to the local Costco store. The pallets full of toilet paper have a thin cardboard that is placed between toilet paper bundles. As people buy the toilet paper, the packing material gets discarded. I just grab a couple and roll them up and stick them under the bottom of my shopping cart. Then at checkout I tell them and they always say "no problem". It's about 4' square and PERFECT for making patterns for stuff. I consider it as doing my part to "repurpose" something. (Gawd....I hate that word)
@jvo If you pre-stretch the metal first, the bead roller won't have the distortion you are experiencing.