How can I bend 1" tubing?

Discussion in 'Motorized Bicycle General Discussion' started by Russell, Jan 2, 2011.

  1. Russell

    Russell Active Member

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    I am looking for a method of bending 1"OD .058 wall steel tube for a bicycle frame. I do not have a 1' manderal and have not had any luck with the sand fill method. I will be greatful for any help.
     
  2. wileydavis

    wileydavis New Member

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    What radius? If you can get away with a large radius, you can just bend it by hand (slowly) around something large and round. I bent the 1' x .049" top tube on my bike using two 18" particle board discs routed to form a half round. See pic. I also used this to bend the chainstays. Even on the .035 wall chainstays I didn't get any wrinkling.

    [​IMG]

    [​IMG]
     
    #2 wileydavis, Jan 2, 2011
    Last edited: Jan 2, 2011
  3. Russell

    Russell Active Member

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    I was kinda thinking of doing something like that. But the drop loop is a pretty tight bend and I was worried about getting a kink.
     
  4. Russell

    Russell Active Member

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    I just measured an old cast iron 3/4" EMT bender. It starts out a 1.030" and ends up at 0.960. It is to big to fit in my lathe so I will attempt to take a file to it to open it up to 1.020.

    If so I can bend the tubing using it the way the tool was designed or perhaps build a backer and use it in a manderal type setup.
     
  5. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

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    You can go to most any small muffler shop & they'll be able to bend it for you (most likely for free.) :)
     
  6. The 26incher

    The 26incher New Member

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    Have you tried to fill the pipe with water and freeze it then bend it?
     
  7. NunyaBidness

    NunyaBidness Active Member

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    I'm thinking that would crack the pipe he was trying to bend. Sand would probably be better to fill it with, tightly packed sand would help keep it from kinking.
     
  8. Russell

    Russell Active Member

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    That was also something I was thinking about. There is a small muffler shop that I have bummed scrap exhaust pipe from. The downside is that I won't have control, as most of my work is trial and error.
    Thanks everyone, looks like I'll try the modified EMT bender.
     
  9. Russell

    Russell Active Member

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    #9 Russell, Jan 3, 2011
    Last edited: Jan 4, 2011
  10. wileydavis

    wileydavis New Member

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    Do you mean a mandrel or the die? You shouldn't need a mandrel to bend .058 wall tube... not for 1" dia anyway. A 6" radius would probably work for a drop loop, which isn't so tight that a mandrel would be necessary.

    I've had better luck in the past with ice than with sand. You could also try cerro bend, a low-melting point metal alloy... kinda nasty stuff though... and not terribly cheap.
     
  11. Russell

    Russell Active Member

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    Wiley,
    Yes you are 100% correct, I should have used the word die not mandrel as the items for sale are dies. I will also try the ice method. Perhaps the ice method would work good if I used it on a form as you suggested.

    Thank you for the correction and suggestion.
     
    #11 Russell, Jan 4, 2011
    Last edited: Jan 4, 2011

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