How can I bend 1" tubing?

Russell

Russell

Well-Known Member
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.
 
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.

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wileydavis said:
What radius and wall thickness? 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.

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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.
 
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.
 
Venice Motor Bikes said:
You can go to most any small muffler shop & they'll be able to bend it for you (most likely for free.) :)
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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.
 
The 26incher said:
Have you tried to fill the pipe with water and freeze it then bend it?[/QUO

One thing is for sure it would be no problem freezing the 6 ft tube. Just leave it outside for an hour. I will try that method on some scrap tubing just to see how it works out. I doubt that it would crack the tubing if it was filled and left veritical while freezing with the top open.

In my teen age years I did sand filled bending but results were mixed 60-40 failure to sucess. More than likley due to lack of skill.

I saw some bending mandrels for 1" dia tube. However the shipped cost was around $200.
Two much for just one bike build.
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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.
 
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.
 
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