TFS: Tube Bending Basics 1 - What You Need to Know

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81,000 welcome to another episode of the

fabricator series with yours truly

so strut tower braces bash bars roll

cages roll bars and miscellaneous pieces

of to all have one thing in common when

you get to fabricating all of these

they're all going to need to be bent so

that's we're gonna go over right now a

2-bit in basics


a lot of people tend to get confused -

versus pipe now both of them are around

in shape both of them having wall

thicknesses they're identifying size and

both of them have the same number to

identify their actual size or reference

so in this case we have inch and they

have two then we have inch and a half

pipe let's start with the tube tube is

measured on the outside diameter or the

actual size that it is and it also has

an identifying wall thickness was the

actual measurement that it measures out

to so in this case this is an inch and a

half OD with a 120 wall which means it's

an eighth of an inch thick pipe on the

other hand this is based on measured on

its inside or nominal inside diameter so

the outside of this is about 1.9 inches

round and the wall thickness is referred

to as a schedule so in this case its

inch and a half scheduled for T now

since this is pipe and it's measured on

the inside diameter that means I can

actually take this ancient have tubes

live inside of the inch and a half pipe

both of them are inch and a half that's

what the rare or referenced as but both

of them don't actually measure to inch

and a half only tube does and only two

is used for making roll cages now that

we've got the differences in materials

figured out let's talk about the bender

this is very very popular to do when

trying to save some money in bending all

of your materials there are two benders

and there are pipe benders now one is

really not supposed to be used with the

other one for a couple of reasons let's

just go over real quick the tubing

bender when you stick your tube into the

bender itself and you lock it down the

tube will actually be pulled or drawn

around this bond of this die itself go

through here and I'll actually pulled

bent around it now most tubing benders

will actually sell pipe size dies and

you can do the exact same thing with but

one way to identify the pipe is by

looking at how it's set up in which case

that is usually set up with a hydraulic

press and a little bending shoe right in

the middle of it that presses up against

the center of the pipe itself and what

that will do is eventually form and kind

of wrap it around there now while that

does work for pipe as a material it's

actually terrible for

there are millions of hacks and tweaks

and ways to try and get tube to work in

a pipe vendor but take it from me save

yourself the time and hassle by a tubing

bender if you plan to bend tubing all

righty so three words that people

typically get confused with regarding

bending dies

center line radius Center meaning the

center of something line meaning in

reference point and radius meaning half

of a circle which if you pay attention

in geometry class you know that the full

circle is diameter half the circle is

radius so in this case we have our diet

and each die has its own size that it

bends this one is Eames and 1/2 this one

is one-inch each one also has its listed

centreline radius this inch and a half

die is a four and a half inch radius for

centerline radius this one-inch die is a

3-inch centerline radius what does all

of that mean well let's actually break

this one down centers meaning a

reference point in this case it's the

center of the tube itself so this

section here would be the center of it

this section also the center of it this

section any point at least within this

tube or at least within the points where

it actually starts at the bend itself to

create that radius is the point where

it's going to be reference so anywhere

in here all of this is your centerline

of course my hand a little squiggly on

this one but you get the idea

line meaning the actual point of

reference were measured at so again when

I traced around so a centerline which is

this area and radius meaning half of the

circle so we'll show you want to die

here every die obviously centered since

this is a semicircle or it is round we

have a center point which is right here

in the middle of it and to the center of

the actual tube itself where the bend is

that distance between the center point

here and the center point of the tube is

your centerline radius okay so the

larger the number you have for the

centerline radius the more gracious or

more gradual your bend is going to be

the smaller the number the tighter the


do you you're gonna end up with okay so

this is where a lot of people ask me and

I'll tell you every single time the same

way what size died do I get when it

comes to bending stuff like cages or

bash bars or whatever the case is now

the answer that one really is entirely

up to you theoretically you're supposed

to measure out what exactly you need for

each one now say roll cages for instance

you're not allowed to have too tight of

a bend and of course you don't want to

have to gradual of a bend because you

know there are some areas inside of like

a chassis or the body of a car where you

know the tube might not fit if it's you

know a th centerline radius that'd be

kind of ridiculous so most rules will

specify the general rule of thumb and a

general rule of thumb for identifying a

centerline radius is diameter times

three so no matter what the bend radius

is or whatever the rulebook specifies

they almost always follow that one so at

bare minimum when you get a die and you

intend to bed roll cages for example out

of that specific size diameter times

three is a safe centerline radius to

purchase now if you're doing the math

inside of your head make sure that you

get your numbers right so if everything

is based off of the center you've got to

know that if you've been less than 180

like this piece you'll know that the

center line radius is four and a half

inches not only leads from Center to

Center which means from Center to Center

you have nine inches wide now if you go

all the way to the outside of each bed

you'll know you have a ten a half inch

wide Bend total getting the inside of

that Bend will be seven and a half

inches so just make sure that you do

your math correctly and know that when

you get a half-inch centerline radius

that you'll know your total width the

total inside measurements


a little bit about the dies with

centerline radius let's actually break

down the nomenclature of the bender

itself this is my bender it is a G B

squared model 3 a lot of people will ask

me how I like it and in all honesty I'm

actually you could probably consider

this a step down to what I used to use

which was the tube shark and honestly I

believe in this mechanical bender here

or a manual bender it's I have a lot

more control out of all of my bends and

actually I really prefer it over the you

know big heavy expensive models so this

isn't actually a great bender and a lot

of people would say how would you rate

this for let's say beginner to advanced

is is exceptional it actually really it

has done everything for roll cages the

tube chassis and everything in between I

love it so this section right here the

main section right here is your frame

link this is essentially what holds

everything to at the stand holds your

ratcheting assembly your ratchet arm all

of it goes on to the framework itself

all right next up we have the drive link

in this section here when we plant the

dyad and we swing this along here this

is what's actually going to move the die

around and make our bend then have our

die this one being my inch-and-a-half

die with a four and a half inch Center

no one reads pin goes in the middle

holds everything together now notice

that these two swing independently of

each other so we have our drive pin now

each die has its own contour its own

profile cut into it now the idea behind

this is it will hold the walls together

and not allow the outside of it to crush

inward and not course let the inside

kink now every manufacturer will have

their own die profile that they cut of

course you have to have the follower now

the follower is for the outside of the

tube to keep that same profile cut into

it when we set the die in here or the

follower in here along with its pin you

now have the ability to throw a tube

inside of there and start bending it

gravel am I gonna have to

with our TBA also has a pin and we'll

lock it in there normally that would be

in there very tight take this and you'll

start bending little by little and go

all the way around now if you've watched

any of my other videos where I reference

a lot of bugs to bending or I do a lot

of tube bending you'll see me do two

things and when I before I start my Bend

one of them is setting my dial to zero

but that is after I set the preload now

you notice that in here we have a little

bit of looseness okay before the tube

actually starts to contact the die and

the follower that's preload when you're

set to zero and it's ready to start its

Bend immediately when that happens you

set your die right on your zero mark and

then you make your bed of course this

follows around the pin will follow

around and you eventually stop wherever

your Bend angle is that you need to make


now there was one more question that I

receive a lot from viewers and whatnot

when they write in and ask about bending

so here it is you'll see a lot of

manufacturers JT squared in particular

also does this they sell dies in 90

degrees and 180 degrees which one should

you buy Wow that choice is entirely up

to you because they are two different

prices and of course 180 degree is

normally more expensive than the 90

degree now how often do you actually end

more than 90 degrees well if you're in

the off-road industry and whatnot like I

build a lot of parts for those and they

tell you like shock hoops and stuff like

that they start around 120 degrees and

go up to 180 so it really all depends on

if you're planning on doing that some

model benders for example they're a

little bit difficult to make a 180

degrees worth of a bend

I agree doc because you have to make

them back-to-back and made that

transition in between there's almost

always something a little bit of a gap

in between there because it's very very

hard to set that up now which one should

you buy what that choice is entirely up

to you but if you ask me personally I

always say go ahead and go with the

hundred eighty degree because you just

don't know when you're going to need to

bend more than 90 degrees now we get to

the fun part this is before we can

actually start bending anything there

are two things that you need to know or

at least one that you really need to

know on the other one you should always

have on hand because there is an easy

method dependent the first thing you

need to know is your cost of material

per Bend

or how much material it takes you to

make let's say a 90 degree bed or

anything in between including 180

degrees any Bend that you make on it you

need to know how much material it

actually uses throughout that bed in any

one of these beds or any Bend that you

do and you need to do this for every

single sized die that you have it's one

of those things that you have to have

them out of your head or at least know

before you start calculating all my pins

the second thing you need to do is

create a cheater and we'll go over the

cheater and how that works a little bit

later but I'm definitely to show you how

to make one of those right now so let's

start with our cost of materials to

calculate our actual cost of materials

we're gonna create what we call a

bending gauge and what we're basically

going to do is take a piece of tubing of

the size that you're going to bend the

wall sizes are relevant and we're gonna

mark it you have one inch increments on

our actual tube here and then we're

gonna throw it in the bender toss a

ninety on it and then we'll actually

figure out how much material it takes to

do ninety degrees and we'll measure out

all of our degrees subsequently in ten

degree increments as we go along

so first we'll need to start out our

star placement or actually calculate

where our start of our Bend is actually

going to be so we need to have some

material away from the die that will

actually strap and hold to the actual

die itself with the with the strap or

the or the tube stake you know whichever

one you want to call it s so we're gonna

start at four inches now I'm just going

to use the actual seam of the tube here

as it as a reference so it's gonna be

pointed upward inside of the bender

there which will actually be our center

line on the center line radius itself

and we'll just

we'll just start making some increments

here at one inch so let's see we'll go

up to up to twelve let's say 13 inches

well that's what we're run-up to so all

of these kind of straighten and thicken

them up a little bit

these are all of our one-inch reference

points then we're gonna load up into our

vendor here and this being the start of

our Bend just make a be there

now we'll go toss that in the bender

all right we'll load this up and make

sure that our seam here is when I said

was gonna identify as our center line is

actually with or along the center line

of the die itself and the start of our

bend at the die is where I'm going to

line it up that's basically point zero

our stay crank this down down here

because you don't want to slip as you're

bending it if you slip you'll cause

kinks so if you're not sure about how

much force you want to apply to this

throw a dummy tube in there and crank

that sucker down what you want is nice

and snug so it doesn't slip and you

definitely you don't want a too snug to

where it's gonna collapse the wall or

leave this massive indentation in your -

so once you figure out where that is -

just get it nice and snug in there we're

gonna pre-loved and set our dial on zero

okay every 10 degrees I'm gonna make

another mark on this too

there's one all right so we're locked

right on ten degrees now we're gonna

make a mark right at the follower on the

tube itself make sure that it's nice and

dark and that you can actually see it

now we're gonna set this up again and go

to 20 degrees there's 20 so you make

another mark at the follower we're gonna

keep on going every 10 degrees and make

another look all the way up until we get

to 90

there we go now we'll take this out and

calculate okay so we have out and what I

did is created a starting point this is

where the impression of the actual

follower is in the tube there and that's

when we are basically ground zero for

all of our angles now for our

measurements of cost of material you can

see all of our black lines still are

still on the tube and of course they're

on the centerline where they need to be

and these we can extend up into the

center line if we actually need to so

let's start with the cost of material

here take a look at your Bend and if you

hold it in the right light you could

probably see it there is a shiny spot

where the actual Bend itself begins on

the tube you'll see a little impression

where the where the dye left on the tube

same thing for its termination where it

stopped which is about right here now

you calculate or add up what's in the

middle one two three four five six seven

and that right there is about a quarter

of an inch roughly in between okay so

seven and a quarter inches that's how

much material it actually takes when

it's in the dye now notice before that I

use my bending reference or the

beginning of the dye as the start of my

Bend in everything that I do in which

case you'll add the extra three quarters

of an inch to this one which is this far

away here and you get eight inches total

now I typically in all of my bends I

usually add the tolerance into it now if

you watch that say the roll cage video

for example you'll notice that I had a

bending tolerance with everything and

I'll say that my die cost me about eight

and a half inches so in all actuality

you just need to know that the total

from the start of the bend to the

termination of the bend in the actual

die the impression that the leaves is

seven and a quarter inches on this die

now if I add in my additional to the

point of how much material I need from

the start of the die in the bender

itself then I know I need eight inches

and then I'll add my tolerance into that

later now you can check out some of the

other videos in the list and whatnot in

the links that I put up here to see a

whole lot of that visual

or that in action and then you might

have a pretty good understanding of how

it works then now what are all of these

little ticks for on all of these angles

that we created here now that's for

measuring each individual angle and how

much material it costs you to bend it so

we already know how much material it

takes to bend 90 degrees how about all

these other ones which we mark these in

10 20 30 40 50 and so on all the way up

to 90 so how do we calculate all of

those well look carefully here the start

of our Bend which I already made the

reference on this one is at the point of

zero here how much material it takes in

that Bend itself so what you basically

need to do is take a measurement here

you'll start at the let's say a 10

degree bend to the actual start of in

itself here looks like three-quarters of

an inch away so 10 degrees takes three

quarters of an inch 20 degrees we'll say

one yeah it's a little little tick over

there so say it's about one two and a

quarter inches worth of material that it

takes and then you go over here to 30

degrees take so just under sets about

know one two and a half-ish and then you

just keep on going so on and so on and

so forth so now you can check out some

of my other videos and I'll put the

links up in here and of course down in

the description if this still doesn't

make sense to you I do reference and use

this a lot so you can absolutely follow

along there and if you're still not sure

on top of that drop me a question I'll

do my best to actually describe all of

this in reference to the video here and

all the rest of that good stuff so if

you have a question drop me a you know

comments email and either the social

media outlets of course you can post up

there and I'll do my best to get back to

you so this is essentially your bending

gauge now what I usually do is kind of

set this aside and put it into a pile

along with you know the cheater and all

the other ones I have dozens of these so

if I ever need to go back and reference

if I don't remember for example how much

material I need per angle then you know

there it is right there I can always go

back and check this out so that's how

you make your bending gauge


now we're gonna move on to making the

cheater you know what is a cheater well

here's the best way I can describe the


it is a been in which case this is 90

degrees and I use 90 degrees for all of

my cheaters unless I need something

specific which sometimes I'll make you

know I'll let make like a 70 degree

cheater or whatever the case is so it

basically is is the actual Bend that

you're using with the dye and tube that

you plan to use okay and it has your

reference cut into it the reference is

the point where you will start and

measure all of your bends from in which

case my beginning reference is always

referenced at the beginning of the dye

so like see on this one for example the

impression left on the tube is a little

bit distance right there you can

actually measure this out or whatever

the case is from the beginning of the

dye so just as we placed earlier when we

made the bending gauge the inside of the

dye at the start of the dye the same

thing goes with the cheater you always

want your reference wherever that is it

can be it can be anywhere as long as you

use the exact same reference throughout

the entire process of all of your

bending and measuring and whatnot so

this is a cheater already made of course

I can tell you how to do that or I can

show you take any length of tube this

one is let's see 17 inches long which

that's fantastic we already know that we

only need eight inches in between and

we're gonna start the beginning of our

Bend now let's say for long we'll go

four inches four inches is a decent

start of a band for a cheater this our

starting point we'll label that Bend go

toss it in the bedroom

just like before the start of our bend

or the start of the die is the beginning

of our been release that's the one that

I'd like to reference can you use

another starting location or a new

reference location yes you can use any

one that you are familiar with or

comfortable and using you can use the

beginning of the follower you can even

use the the tube stay if you want now

it's important that you identify and

know and repeatedly use the same

reference as the beginning of your bed

which every single one of my dies I

always start

the beginning of the dye as my reference

you can again you can use the stay you

can use the end of the actual stay block

itself you can use anything that's going

to be a repeat and reference it doesn't

really matter what it is but it is very

very important that you always and I

really mean always use the exact same

reference if you change reference in the

middle of a project let's say you're

building a a main hoop for a roll cage

and half of it is used as the starting

dye reference here and the other half is

used with the follower you're not going

to be able to bend it and and maintain

that kind of consistency inside of your

build so again whatever it is that you

intend to use as your reference make

sure that it's the same throughout

everything and if you choose to use two

different references you need to bend

two different cheaters okay so after you

have it locked in here crank it down

dial on zero preload a set let's go to

ninety degrees let's just continue this

line all the way around to make it as

straight as possible of course you

watched my other videos you'll see that

I actually insert the tape measure for

the end of it into the bend itself so I

can get an accurate measure so your cut

needs to be wide enough actually hooking

inside of there in which case I usually

just use the chop saw to slice down on



now of course I did actually rotate the

tube so I can get a much more broad cut

around the tube in the areas where I'll

likely be measuring so I'm going to do

is set this up one more time here I'm

gonna try and set the tube up where it's

exactly where I was before of course you

want to make sure that it stays exactly

in line with the other kind of you just

made now those insides and whatnot we

can actually go on there chase them out

with a file if you want but now you have

a means of measuring where the start of

your bend is going to go versus where it

actually sits on a vehicle or a chassis

or the project and what you are bending

so let's get to the bending