Bending brake isnt giving me the right bend radiu

Discussion in 'Pitts Model 12' started by FastEddie, Aug 5, 2010.

  1. Aug 5, 2010 #1

    FastEddie

    FastEddie

    FastEddie

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    Hey All,


    I had a problem with getting the correct bend radius when making my heeltrays in a bending brake (not a press brake) and I wondered if anyone can tell me what I'm doing wrong.


    I needed to make a 90 degree bend with a .125" radius in a piece of 0.050" thick 3003-H14 aluminum.


    I adjusted the setback to 0.175" (0.125" radius plus 0.050" material thickness) on the bending brake. When I made the bend, the material bent right at the clamping point with a really tight radius (0.025-0.050") instead of the 0.125" that I should have seen. The grain of the material was perpendicular to the bend line.


    Do I need to also insert a piece of material with a 0.125" radiused edge into thebrake on top of the aluminumto act as a 'former' to keep the radius correct? Will I have this same problem with steel as well?


    I'm really confused. I followed the set-up instructions to the letter and even double-checked everything, but the bend kept coming out way too tight.


    Thanks in Advance,


    Ed
     
  2. Aug 5, 2010 #2

    Beej

    Beej

    Beej

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    <Do I need to also insert a piece of material with a 0.125" radiused edge into thebrake on top of the aluminumto act as a 'former' to keep the radius correct? Will I have this same problem with steel as well?
    That's how I did it..I used MDF with a round-over bit in a router..
     
  3. Aug 6, 2010 #3

    cwilliamrose

    cwilliamrose

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    Often you can bend one or more pieces of sheet metal in the brake and use these as your radius bar. Here a single piece of .063" used as a radius bar for .093" material. It's just a quick example from our pile of "tooling" for the brake. This is easy to do if you have some scrap sheet metal laying around.

    [​IMG]

    ...................Bill

    Edited by: cwilliamrose
     
    taff and christopher like this.
  4. Aug 6, 2010 #4

    FastEddie

    FastEddie

    FastEddie

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    Thanks guys. I admit I was surprised when the bend radiusjust didn't work out automatically. That's what happens when you forget to adjust for "Murphy's Law".
     
  5. Dec 21, 2012 #5

    taff

    taff

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    Thanks for sharing this idea. Will keep it in mind.
     
  6. Jan 4, 2013 #6

    verticalroll

    verticalroll

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    Don't forget about the bend radius allowance you will find this in tony bingelis book on bend radius application
     

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