How to bend
Pipe Without Kinking
Introduction to Square Tube Bending @ Trick-Tools
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hi I'm Bruce with trick tools today I
want to talk about something that we
talked to a lot of our customers about
sometimes people struggle with and that
is bending square tubing if you're new
to tube bending you may think about
square as being easier to work with and
around sometimes if you don't do things
properly or have the right equipment
bending around can create some
challenges but if you have the proper
bender you can get a really good result
on round tubing for a low cost you can
see on a tube like this very little
deformation to the tube and this was
done on a very simple manual bender with
round tube you have to worry about
fitting tubes together and cutting a
notch in the end of the tube that takes
a little bit more time or more equipment
sometimes with square tubing you can
simply mitre cut or just cut to ninety
degrees the end of your tube and fit it
up against another piece of square that
that is a simple way to fit the tubes
together but the bending process can be
a little bit more complex
bending square tubing can be a little
bit more frustrating if you don't
understand the challenges so we hope to
clear some of those things up for you
today and show you what the differences
are almost all of our two benders will
Bend square tube it's just a matter of
having the right die so this die as you
can see has a square slot in and it also
has a little bit of a bump in the middle
and the reason for that bump there is to
be able to push the material on the
inside of your square in just a little
bit so you need to have this happen
because there's so much shrinking and
stretching going on on a square tube in
that you have to give it a little bit of
a push in the right direction so in this
case you can see this is a one inch
square o 65 tube and it obviously has a
little bit of caving on the inside and
outside wall of the tube now you will
always experience this with square
tubing
unless you have very sophisticated
bending equipment that can cost upwards
of $50,000 or more a bin like this can
be achieved with a simple tube bender
either manual or hydraulic and it just
requires the proper die now you can see
on this bend o 65 wall gives you a
little bit more deformation of the tube
then this 8-inch wall actually has very
little so the heavier the wall thickness
of the tube the the nicer the quality of
Bend you can get it also has to do with
how how broadly you bend it or the
radius of the bend if you bend it on a
bigger radius die you're gonna get less
deformation if you bend it on on a real
tight radius like this you're gonna get
a little bit more now this is some
aluminum tubing that can also Bend
easily on on a tube bender and you can
see the result here with a little bit of
a little bit of dimpling on the outer
wall and here you're pushing the inner
wall in to be able to allow that to Bend
without without collapsing one of the
challenges that people often experience
with square tubing is that when you bend
square it tightens into this square slot
so unlike round tubing where it can fall
right out of a round slot in square you
bend it and the tube will expand into
this slot and become stuck so you may
need to have a mallet or a hammer and
actually hammer your tube out of the die
to be able to get it free now as you do
more and more degree of Bend for
instance like this hundred and eighty
degree Bend then it becomes a real
challenge because so much of it is
pinched in that die opening the die up
and giving yourself more clearance on
the die doesn't necessarily help because
it just allows the tube to expand that
much further into the die so we've got
several square samples here some of
these tubes as you can see like this two
by three rectangular this is bent with a
lot of deformation
and that's done on purpose to be able to
bend a thin wall thickness to a real
tight radius sometimes this is a more
economical way to do it now this could
be done with no deformation to this Bend
but again the machinery to do that
probably getting close to $100,000 to be
able to do that so a typical a typical
square Bend is going to have this type
of dimpling happening on the inside
radius and a little bit of this
deformation on the outside radius so
depending on your application that may
be perfectly acceptable for some it's
not acceptable at all obviously if you
were bending square solid like this
square bar here then you can just bend
it with no problem and there's nothing
to collapse so again it's it it's a
relationship between the wall thickness
and the radius that you're bending how
much deformation you will experience so
let's take a look at the actual bending
process okay so we've got a simple
hydraulic machine here we're gonna bend
a piece of one inch o 65 tube just to
give you an idea of the process with
this rotary draw style machine it uses
they call a you strap to pull the tube
around the radius die and I think we're
all set here
so as I extend this hydraulic ram out
the tube gets pulled around the radius
die and is formed by this follow bar
here so we're just going to run out to
about a 45 degree Bend
and then our cylinder limits out but
that's where we want to stop for this
Bend so the thing was square it would be
now to relieve the pressure slightly but
not to return the die all the way back
under powering the thing that I want to
do now is relieve release this tube from
this follow bar or a counter bend I once
I've got the two broke loose by tapping
on at this direction now I can take my
follow bar off
and I can return the cylinder back
now the tube is wedged a little bit into
this forming by but that can usually be
lever down or tapped out with a mallet
to release this direction
so as you can see we've got a nice
successful bend in our square tube here
on the outside you've got just a slight
concave shape for where the outer wall
started to pull in on the inside you've
got a little bit more of a dimple where
the dye actually pressed the inner wall
in but the sides are nice and flat
giving you a nice strong Bend for a lot
of applications we hope we cleared up a
few things for you today gave you some
ideas and please feel free to give us a
call if you have any questions at trick
tools Thanks
