bend

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