sup fabrication nation welcome to the
channel today i think i'm going to spend
a little bit of time and go over pie
cutting so the popular thing these days
is to pie cut tubing to make bends not
necessarily my preferred method of
welding or making bends but that doesn't
mean that it's not a good way of doing
it and I get a lot of questions about
how to do it so without going into great
detail I'm going to spend a little bit
of time show you how.... give you some
pointers give you some guidelines to go
by when doing pie cut bends and maybe
show you something that you didn't
already know all right so pie cutting
creating bends with pie cuts is for you
for anybody out there that doesn't know
it's basically taking sections of
straight tubing cutting them out of pie
shape and then when you stack them
together you can actually create nice
smooth bends... okay now obviously you
could just go start cutting all kinds of
pie shaped pieces of tubing and weld
them together and you have a pie cut but
there is kind of a proper way to do this
a professional way to do this I don't
really prefer pie cuts myself so im not
necessarily an expert on this I usually
just go with a mandrel bent tube I buy
mandrel bends and then put those bends
together to achieve what it is that I
want to achieve just because I don't
prefer it doesn't mean it's not a good
method there are some pros and some cons
to pie cutting and mandrel bends both
there's also a place for pie cutting
there's certain instances where you
can't necessarily Bend tube mandrel bent
tube to the radius that you need or the
material itself is
not very bendable and in those cases pie
cutting is a must there are actually
several companies already out there that
do pre-cut pie cutting for you most of
its laser cut it's very precise and
exact one of those companies is called
ticon ticon basically does titanium
tubing of all sorts you can see mandrel
bent stuff to being exhaust anything you
basically need they can do for you the
reason I bring them up is because they
do offer a sample kit so they offer
sample pieces of titanium that are
already pie cut it's a very well priced
kit they're not very expensive and in
those kits they'll send you some filler
rod some pieces of pie cut tubing and
different sizes and some pieces of
titanium plate so if titanium is
something that you wanted to experiment
with you can go get one of these sample
kits from them all this is unpackaged
but when you get it it will be nice and
sealed package them pretty ticon ticon
industries com actually sent me this kit
plan to experiment with it at some point
never really tried my hand at titanium
I'm going to give it a try and maybe use
it for like wastegate tube on the bid
stir something where it's nice and clean
and cool as long as I can pull it off
alright so let's talk about some of the
pros and some of the cons to pie cutting
some of the pros would be you can get
tighter radiuses then you might be able
to get with mandrel bending you can use
materials that maybe aren't very good at
bending like the material itself might
be too brittle to bend it so if you pie
cut it you can actually achieve what
you're looking for in some instances it
might be cheaper to buy straight tubing
and pie cut and creates your bends versus
buying a mandrel bent tube alright so
now let's get into some of the basic
theories of pie cutting
and kind of the right way to do it so
pretty much what the standard is is
either a 9 degree pie cut so four and a
half degrees off either side of center
so if this is a tube and you mark a
center line you want to go four and a
half degrees one way four and a half
degrees the other way and you have a
9 degree pie cut the other way is an
18-degree pie cut so this was a straight
tube you'd have a 9 degree cut in a 9
degree cut equaling a total of an
18-degree pie cut the reason that these
are pretty standard is because you can
achieve the angles as you want the easy
angles very simply so if you have a 9
degree pie cut 10 of these makes 90
degrees it's easy for you to do that
five of them would make a 45 degree and
then basically the same thing when you
have an 18-degree pie cut it only takes
five of these to make a 90 degree angle
and you can see when you use a 9 degree
pie cut when you stack several of these
together you can actually make a very
nice smooth radius on the inside some of the
other pros are you don't get any
shrinkage through the bend so even in
mandrel bent tubing you do get some
shrinkage through the bend itself and
pie cuts you don't get that these are
all straight tube so if this is a you
know two and a half inch tube you're
going to get a true two and a half
inches of your radius through the bend
some of the downfalls to pie cutting
obviously the labor you have to cut and
weld so many little pieces it's kind of
a disadvantage another pro to pie cutting
is you really kind of have unlimited
access to clocking of angles so as you
are doing a band you can start to rotate
these and create all kinds of complex
curves and bends it wouldn't necessarily
be as easy to do with mandrel bends you
could you could chop them out and
basically pie cut the mandrel bends
themselves but wouldn't be as easy to do
a need that's enough about these let's
go over here to the bench and I'll kind
of show you how you want to lay these
out in a fashion that
give you a give me the same cut
repeatability and allow you to make
really nice lobster or pie cuts all
right let's play something out here to
scribble on alright so we're going to do
is I'm just going to give you the very
basics to the proper way or at least a
good starting point to lay out tube for
pie cuts so the first thing that you
need to do is you need to figure out the
distance around your tube alright so
what you want to do so the first thing
you want to do is going to measure the
diameter of the tube which is obviously
the distance across the tube itself so
from one side to the other a diameter
and on this one we're going to say it's
four and a half so 4.5 is the diameter
and you want to multiply that by pi
which is a 3.14 that is going to give us
14.1 three so 14.1 three is the
circumference around this tube alright
we want to find out is we want to find
the halfway mark perfectly half way
through this tube here so we're going to
do is we're going to take 14.1 three
we're going to split that in half and
divide that in half it's going to give
7.065 okay so we know that 7.065 inches
around this tube from this point here is
going to be perfectly half way around so
it's going to give you basically your
perfect halfway through this tube now
the reason that you want to know this is
because this is going
to be critical as far as cutting and
lining up the tubes themselves because
we're going to mark the to you halfway
so you can see these marks on this tube
here that is the halfway mark when you
mark the tube halfway before you cut it
it allows you to cut those angles
perfectly square ok every time and once
they're cut it's going to allow you once
you line these up you know that you're
going to have a perfect 90-degree Bend
it's not going to waver any as it as it
bends as long as those line up it'll
also allow you to clock these things
purposely alright so these are these
here at hand mark before they were cut
if you get them from ticon or a company
like that a lot of times they'll have a
weld seam on the inside have a weld seam
on the inside here as long as you line
up that well team you know that it's
going to be exactly the same throughout
that bend alright so using this formula
you take a long straight piece of tube
which essentially would look like that
right so essentially that's what that
tube looked like before it was cut
there's a straight tube I've got a line
drawn down this side got another line
drawing the other side's achieve that is
perfectly opposite of this line and all
you have to do is Chuck that thing up in
your bandsaw or whatever you're going to
use to cut it make sure that this side
is perfectly the highest point up and
then to start cutting for half degrees
four and a half degrees for a half
degrees four and a half degrees in
perfect world you kind of want these
inside pieces here to match so you want
all the inside distances to match or be
very close
if you take that straight tube and cut
it up into a bunch of pie cuts that are
exactly the same you will then be able
to put these together and make nice pie
cut bends so you can see how that works
once again measure the diameter of the
tube times it by pi 3.14 that's going to
give you the circumference split that in
half that's going to give you your
perfect halfway point once you figure
that out draw lines down the entire
length of the tube that are opposite of
each other you want them to be perfectly
opposite of each other and then just go
down and cut once you've done that
you've got all your pie cuts then you can
kind of put those together as needed
usually you'll just want to tack it
together as you create it and then once
you have what you want then you can go
back and weld it all up all right guys
there you go a very easy introduction to
pie cutting and making pie cut bends
that's so what you want to do it those
are the basics of it the rest of it you
can kind of figure out on your own there
are some very in-depth videos on YouTube
about pie cutting if you kind of want to
look into it more I know the fabrication
series does one I'll put maybe a link to
that video in the description if you're
not familiar with that channel you can
go check it out like I said that's the
basics there that's all you really need
to know to get started and make nice
professional clean looking pie cut bends
I hope you guys enjoyed that as always
thank you for joining me and uh I'll see
you guys tomorrow go do work son
