help figuring out how to cut steel tube / mandrel bend :(

[imcool]

I've completely wasted all materials, time etc in this project.

I cant figure out how to cut two mandrel bend in a way so i can move them either at -x , +x or +y or -y. i want to cut them so they match exactly and go where i want them to go.

What i did was i cut only one end of mandrel bend and tried to match it other side,

for example, i wanted to move #2 from photo towards the engine block i.e. -x axis so I started cutting and grinding #1 but I ended up making it worse and kept cutting and I made side 1 of mandrel shorter and still 1+2 wont go towards -x axis, the I tried grinding #2 side as well but they never fit for me

Same issue happened when I tried to align #3 and #4 so they will go perpendicular on bottom pipe at #6 but again I kept cutting at angles on #3 and nothing aligned

Between #7 and #8 I tried to move them +z and -z , kept cutting and never got it aligned and never got it to fit with minimum spaces between joins.

I used angle grinder for cutting by putting tape after measuring angles on mandrel bend. I watched 100 hours of YT videos on how to draw angles on steel tubes, i think I cut them alright but couldnt figure out how to move them so they can fit.


I gave up after wasting 2 weeks to cut the bends.

I hope someone can help me out here, I have ordered new bends, band saw so I can start over again.

Thankyou for reading

[SweetMK]

I would stop at a muffler shop,, with a pizza and a dozen Dunkin's,,, and ask for a little help.

Those guys could do this with their eyes closed,, while they are sleeping,,

[Oldiron2]

It would be better if you hand-drew a sketch showing what you want the whole thing to look like when done; I don't have the time or energy to read the description again and then figure out what it's all supposed to mean.

[tapwelder]

Print a template?

Bend-tech software may help you.

[Rex_the_Nerd]

Did you try looking for lake style headers at Speedway Motors? They might have a kit with the parts you need.

[imcool]

I would stop at a muffler shop,, with a pizza and a dozen Dunkin's,,, and ask for a little help.

Those guys could do this with their eyes closed,, while they are sleeping,,

I called 10 businesses around my city and they all said no and they dont have time, they are booked for next 6 months, thats why I decided to take matter in my hands. this is what you get when you live in COMMUNIST COUNTRY AKA CANADA

[imcool]

It would be better if you hand-drew a sketch showing what you want the whole thing to look like when done; I don't have the time or energy to read the description again and then figure out what it's all supposed to mean.

this is how it should look like

[imcool]

All I am asking is how to cut bends couple degress so they fit where i want them to fit,
'
tell me like you are telling to a kid who doesnt know anything about cutting bends.

[SweetMK]

this is how it should look like

All I am asking is how to cut bends couple degress so they fit where i want them to fit,
'
tell me like you are telling to a kid who doesnt know anything about cutting bends.

The photo you are looking at involves creativity and artwork,,
You are asking for a simple math formula that you can punch into your phone, and have the answers pop out,,
That ain't gonna get you to the finished product in the pic,,

Practice, trial and error, learning,, no one can "give" you that,,
Part of it is realizing that for YOU to DO this product,, YOU have to make the inputs to get there.

The image that you show has multiple diameters, They are at multiple angles,, that is not something that involves a simple "math formula".

I thought that headers were supposed to have equal length tubes to begin with??

[tapwelder]

Looks like you only need to form the bend then miter for the lower tube. Then use a straight union the connect the top and bottom.

I agree more art involved there.

You just need matching satisfactory bends and miter. Should be done on a bench off the on scrap. Then just weld in place.

[Oldiron2]

All I am asking is how to cut bends couple degress so they fit where i want them to fit,
'
tell me like you are telling to a kid who doesnt know anything about cutting bends.

There are some basic ideas you can use. If working with two pipes of the same diameter that you want to join at an angle, both need to be cut at the same (half) angle so the cuts are the same length, in order to have them fit together. To make ( to "approximate") a long curve, multiple small pieces may need to be welded together, each joint having the same angle at the cut ends of the two parts. It's more complicated if different diameters; might have to squeeze one and cut it at a different angle to get the same length (circumference of the tube's cut end) to fit the second part.
Get some paper/cardboard tubes (e.g.paper towel rolls, shipping tubes, even toilet paper rolls), or maybe short discarded sections of thin plastic pipe to experiment with.

My fit up and welds below aren't perfect, but they will hold and ain't bad for a freebee quickie stick job:

[52 Ford]

this is how it should look like

What are the headers going on? I see a foot peg in that picture.

[Welder Dave]

First of all Canada isn't a communist country. If you believe it is then move. Most muffler shops don't make headers. The better ones will have guys that can do more complex exhaust but it took them a lot of time to figure how to do it. If they're busy they don't have time to design some guy off the streets headers. You need to draw out what you want in full size and make kind of a jig. It could even be made of wood. You have basically 3 outlets that need to be parallel. Might make it easier to get those figured out and then cut the pieces (#1) that weldthen s onto the flange. Then if the 3 down sections aren't perfect you can compensate when cutting the pieces that weld to the flanges. The length and cut has a little more leeway because of the thickness of the flanges. If you want to start with the pieces welded on the flanges you need to make sure they stick out the right distance. It's much easier working with common angles like 90 deg's., 45 deg's or 22.5 degree's. It will take some trial and error to get it right. If that header was a commercial bought would probably be computer designed. Guessing it's fir a Triumph Speed Triple or other 3 cylinder model Triumph.

[Lis2323]

To repeat what Welder Dave said, I don’t know why you consider Canada a Communist country.

As far as muffler shops go I am certain there are some capable of creating what you need but the cost will most likely considerably more than what you would be willing to pay.

[52 Ford]

To repeat what Welder Dave said, I don’t know why you consider Canada a Communist country.

As far as muffler shops go I am certain there are some capable of creating what you need but the cost will most likely considerably more than what you would be willing to pay.

Commies can't make headers... duh.

Back during the Cold War, that's one of the ways the CIA could figure out if a welder was communist or not.

[52 Ford]

All I am asking is how to cut bends couple degress so they fit where i want them to fit,
'
tell me like you are telling to a kid who doesnt know anything about cutting bends.

Buy a belt sander and use that to fine tune your angles.

[Leogl]

Like the rest of them said lots of patience very creative cuts and lots of grinding with a very fine belt grinder or flap disc