"Christopher Graham" wrote in message
news:wl00e.759956$8l.580013@pd7tw1no...

Thanks for the reference. This: http://www.medfordtools.com/mb3.html
bender looks like it would work.

So, I assume I also need a bunch of dies for the sizes and angles I want
to bend.

I have these questions:

- How close does the tubing diameter have to be to what the die was
designed for?
- Does the die radius exactly determine the bend radius?
- Can the angle of bend be anything up to the angle the die was designed
for?

I have a 4 axis cnc milling machine, so what I may do is order one die set
and use this as a guide to making others.

- Chris



Chris

I will try to answer some of your questions. I'm not an expert, but have
learned enough to know that "simply bending a tube" often ends up not being
that simple. I bend tube for my copper creations and have run into alot of
information trying to get my bends right and using the right equipment.

Each die is made for a specific OD of tubing. So you'll need one set of dies
for each OD of tubing, also for each radius of bend.

There is springback to account for, how much depends on the type of metal
and it's hardness. For example soft copper tubing will have less springback
than hard drawn copper tubing. Yes the angle of bend can be anything up to
the andle the die was designed for.

As far as making your own dies, yes I've done it. However, I know that some
dies for mandrel bending and other specialty bending are not the usuall have
round shape. Don't know if this fact would apply to you or not.

Who ever you buy your machine and initial die from should be able to tell
you what you need to know. Most manufacturers are pretty good at making the
customer happy and selling you a machiine that does what you want it to do.
Just make sure you give them all the information so that you purchase the
right product. Why buy something that doesn't do what you want it so.

Tube bending can be a complicated science. There are things to calculate
like "D of bend" "Wall factor" "bend difficulty factor";
http://www.bendtooling.com/bending_formulas.htm

Reading this guide will help you to understand the science of tube bending:
http://www.hinesbending.com/BASICTUBEBENDINGGUIDE.pdf Granted not all of it
may apply to you, but it will help you to understand exactly what is going
on when you are bending.

Hope this helps.
Lane