Thread: Help with tube bending machine

Hello people

I introduce myself, I am gustavo. I have a problem with a hydraulic bending machine,
the 2 "steel tubes come out without problems but the 2 1/2" and 3 "tubes have a terrible result,
the same happens with the stainless steel in 2". I enclose some images so that you can see my problem,
your advice is greatly appreciated as to why this may be happening to me.


Greatings






Best regards from chile

Hi tavooandres7

Welcome to the MetalWorking Forum

Is the machine a dedicated TUBE or a PIPE bender? There is a difference. Light walled tube does not always fare very well in a pipe bending machine.

It gets down to the wall thickness of the tube or pipe being bent. I think the recommended bending radius for tube will be different to that of pipe There is a formula to calculate this somewhere on the net.



Grahame

Welcome Gustavo. In your picture; https://metalworkforums.com/redirect...186218f1eo.jpg, it appears that your tube/pipe is not sitting in the former correctly. It should sit in the former a little over half way, this is to give support to the pipe/tube as it is bent and stops the kinking that sometimes occurs. You should be able to get the correct size dies/formers from the supplier of your machine.
As Grahame mentioned, pipe and tube formers are different, pipe is measured on the inside diameter, (ID) while tube is measured on the outside diameter (OD).
Have attached charts to assist you with your OD and ID of pipe and tube

https://www.rolledalloys.com/tools/pipe-chart/ https://www.google.com/search?q=tube...hrome&ie=UTF-8

Hope this helps with your problem.
Kryn

Another work around I can recall was to pack the tube with dry sand and use plugs of newspaper to retain it.

In case you are not properly confused yet, I will throw in this.

As an example 2'' tube has a different OD from @'2" pipe which is measured as Nominal Bore.

If the machine is a pipe bender ,2" tube placed in it, will be smaller than the same pipe and therfore will not fit that 2" die and former properly.

Mind you its all bit hazy after 50 years and the pipe benders then were different to what you have shown ,but the principles should be the same.

Check this link out and scroll down to Draw bending,which I think your unit looks like.

https://www.listertube.com/links/tub...-design-guide/

Grahame


Grahame

Hi Guys,

Thanks for the refresher ! I remember some of this from nearly 40 years ago when I was involved in bending 1" pipe and being supplied 1" tube. Very confusing and expensive as I recall.