#11
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Yes Kent. Somehow similar way. It would only be possible to shape it into a cutout and then finish it in EW. For ease of preparation.
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Jaroslav |
#12
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Kent, A couple of questions if I may, 1. form looks to be MDF with a plywood base and clamping plates? 2. The nylon rivet set, do you shape it into a radius? Many thanks
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Neil Morgan Last edited by xlr8tr; 07-22-2021 at 05:29 AM. |
#13
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arrangement of parts for flow forming c.jpg Upper "clamping block" = plywood, MDF, HDF, partikle "p'board", etc Lower "Form Block" = oak, ash, maple, aluminum, HDF, MDF - directly depending on alloy, temper, thickness of metal being formed. P1010658 c.jpg etcetera - MDF upper clamp block and lower MDF form block P1050429 c.jpg "Rivet guns" used for this "flow forming" methodology. This is aviation stuff, dating to at least 1930's - first pneumatic rivet guns circa 1914. NOT "rivet sets" at all - rather, "flow form tooling/tools." Incapable of setting any kind of rivet, nohow. Polymer schnoobles, of varying flavors. Color-coded by hardness. Shaped for offsets, domes, flanges, joggles, etc. ... myriad shapes needed for aviation.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. |
#14
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Kent, I just have a similar assignment you're showing. Looks like I'm will be using Pullmax. I don't know what the idea will be.
Yesterday I tried the repaired tool. I grinded the insert in the tool by hand and I was very angry. My anger did not subside even after a successful test. Tool with plastic inserts ..... I shaped the shape using Eckold, EW and hammer. Al 1,5mm. DSC07690.JPG DSC07692.JPG DSC07695.JPG DSC07704.JPG
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Jaroslav |
#15
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finished bulkheads, 2024-0, ready for treat c.jpg
Making all the bulkheads to rebuild a wrecked airframe, Globe Swift w/210. P1120021 c.jpg Heavy 5X CP rivet gun, and long+ short flow form tools w/various inserts. Gooseneck and offset (pistol) handles still available on some models. (I'm a fan of the gooseneck as it keeps my wrist directly inline with the barrel impacts.) ( trivia: I have reason to believe Northrop came up with the gooseneck in 1947 ... as they won the US National aviation riveting championships that year....) ( I was pleased to see parts mfg done via flow forming at both Erickson Air Crane (Sikorsky S64 models) .... and at Columbia Helicopter (previously CH47 models .... now Boeing Vertol 107 and 234 models).... Many other small aviation outfits make parts for their replacements/rebuilds/repairs this way, also.
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Kent http://www.tinmantech.com "All it takes is a little practical experience to blow the he!! out of a perfectly good theory." --- Lloyd Rosenquist, charter member AWS, 1919. Last edited by crystallographic; 07-24-2021 at 06:51 PM. |
#16
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IMG_5323.JPG
IMG_5329.JPG IMG_5330.jpg IMG_5331.JPG IMG_5332.JPG Following Kents advice I made my form and clamping blocks from MDF, drilled oversize holes in the Ali, annealed using the sharpie method and tried to work evenly and slowly - However as you can see the material tore. So my question is should I anneal several times during the process? Is there some technique I'm missing that would help?
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Neil Morgan Last edited by xlr8tr; 08-06-2021 at 05:03 AM. |
#17
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It is clear. The material braked against the screw holes. The material brakes only between the plates. Try to make only a smaller neckline only to the screws and tighten less. First shape from the edge and finally the center.
The smaller neckline does not have as much tension. Make experiment n. 2 on the same instrument with a smaller neckline. Material only to the screws and tighten less !!!
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Jaroslav |
#18
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Shown above is, basically, a stretching exercise with the material “trapped” by the forms.
Consider the opposite with a slightly different approach - “Slip forming” - also developed in the 30's and 40's. Same basic form and clamp blocks but with the clamping bolts outside the edge of the material and the clamp block relieved or spaced to “trap” instead of clamp the material. If the edge radius into the form is sufficient, the material will be drawn into the form - less stressed, as it both stretches and shrinks while being pulled into the form by the flow forming tool - eventually assuming the shape of the female form.
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Marc |
#19
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Thank you both for your help, I've trimmed the material to just inside the bolts so it's free to slip between the clamp blocks which has solved the tearing problem.
A couple of more issues I've come across, 1. How to prevent the material being drawn into the form pulling away from the edge over the radius - learning as I go so obviously I don't have any real technique or experience to draw on. IMG_5333.JPG 2. How to shrink this tight inside corner IMG_5334.JPG
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Neil Morgan |
#20
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2. How to shrink this tight inside corner
Try what it does. Tighten the bolts more or less. I don't know. I would start shaping this corner first. Gradually, I would shape the material from this corner. Show the tool you are using.
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Jaroslav |
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