Bend radius

Discussion in 'Sheet Metal' started by pfarber, Oct 9, 2019 at 5:45 PM.

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  1. Oct 9, 2019 at 5:45 PM #1

    pfarber

    pfarber

    pfarber

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    The plans I'm working from call for bend radii of various dimensions... .16, .10, .5 inches

    How can I get these radii with any accuracy? I have a sheet metal bender but the clamp's lip in just not something I can take out and change.

    What are some solutions that I can look at??
     
  2. Oct 9, 2019 at 6:14 PM #2

    Angusnofangus

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    One way would be to bend up what would be packers for the clamping bar of the brake. Say a piece of .025, three inches wide and as long as the brake is wide. Bend it as far as it will go, and you now have a new radius bar. You will have to measure it to know what you have. If you want a bigger radius, bend up a thicker piece of aluminum. You will obviously have to adjust the brake clamping bar so that your bends are in the right place.
     
  3. Oct 9, 2019 at 6:50 PM #3

    Winginitt

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    Trial and error.......;)

    What thickness and what length are you trying to bend?
     
  4. Oct 9, 2019 at 7:46 PM #4

    Turd Ferguson

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    Be pieces of various thickness around the nose of the brake until you get what you want, then bend your work piece.
     
  5. Oct 9, 2019 at 9:58 PM #5

    Angusnofangus

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    Isn't this what I just suggested in #2?
     
  6. Oct 9, 2019 at 10:29 PM #6

    TFF

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    Never heard it called packers, but thats what I do.
     
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  7. Oct 9, 2019 at 10:57 PM #7

    Dan Thomas

    Dan Thomas

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    Thicker stuff is just going to crack and break around the typically sharp nose of a non-aviation brake.

    Most of us handle it by making radius strips of thinner material. Start with one, then add another and another until you're at the radius you need. Move the clamp bar back a little each time to allow for the increasing thickness. Mark them so they nest in the same order every time you use them, since the innermost will be bent much more tightly than the outermost.

    And if you can get light sheet mild steel, use that instead. It will bend more tightly than most aluminum alloys without cracking. And it's cheaper. You could make single-piece affairs using 16, 18, 20 and 22 gauge steel. The strips only need to be maybe an inch and a half wide, bent down the middle. A fabricating shop could shear you whatever strips you need.
     
  8. Oct 10, 2019 at 12:31 AM #8

    proppastie

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    .1 and .16 go to the big box aircraft store and get stove pipe for raw material, stack them up as previously stated........ .5 (1/2 inch?).....that is going to be a problem.

    set back of the clamp did not work well for me with hardened material (2024-t3) as the material lifted and bent at where the clamp was and not at the hinge line of the bending bar. I needed the extra pieces bent around the clamp for the resulting larger radius.

    Buy a set of radius gauges or cut out of cardboard because the resulting radius will be larger than the radius of the clamp.
     
    Last edited: Oct 10, 2019 at 12:39 AM

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