Pie cutting exhaust

[GearHead11]

Anyone have experience with it? I have 4" to turn 90* with a 3" exhaust pipe. I've found plenty of pics online and I think it can be done but I'm not sure of the best way to measure the degree of each wedge on a round tube

 

[Black Bear]

you can get a 3" J bend from summit would be "better" than a pie cut exhaust. I have some here you can have if you find your way to Raleigh.


something like this..
http://www.summitracing.com/parts/hok-12399hkr/overview/

 

[GearHead11]

you can get a 3" J bend from summit would be "better" than a pie cut exhaust. I have some here you can have if you find your way to Raleigh.


something like this..
http://www.summitracing.com/parts/hok-12399hkr/overview/

Yeah I've been looking into mandrel bent pieces but nothing comes in a tight enough bend. I found a piece with a 2.5" bend radius and would work but it's 304 stainless and $60

 

[Black Bear]

if you think of the tube a 2d shape, if you draw a line straight across and on the right side of that line measure up 1.25". If you were to connect the starting point of the first line to mark 1.25 up on the right that would be a 22.5 degree cut.

Just keep in mind that the cross section of the cut is larger than 3", in this case it would be around 3.25".

 

[GearHead11]

Where did you get the 1.25" measurement from? I was thinking of doing 6 15* wedges to still keep the bend relatively smooth

 

[Black Bear]

i used a trig calculator.


Trigonometry Calculator

side b is 3 angle a is 22.5

 

[GearHead11]

Gotcha. Had another thought as well.. couldn't I just make paper templates that would wrap around the tube? Figure out the circumference and divide in half to figure out height of paper template then just cut the desired angle, lay it on tube, trace, the repeat on the other side of the tube?

 

[Black Bear]

That sounds like a good idea..

 

[Fabrik8]

Do you have a band saw or chop saw to cut the tube? You just need something to clamp the tube at an angle to the blade, so it really doesn't matter if the tube is a tube becsuse you can set everything up in 2D. Am I missing something here? It's no different than cutting a piece of hot dog at an angle with a knife on a cutting board.

 

[GearHead11]

Do you have a band saw or chop saw to cut the tube? You just need something to clamp the tube at an angle to the blade, so it really doesn't matter if the tube is a tube becsuse you can set everything up in 2D. Am I missing something here? It's no different than cutting a piece of hot dog at an angle with a knife on a cutting board.

I tend to over complicate things.. All I have for cutting is an angle grinder. I'm going to take it to a buddies next week who has a nice standalone bandsaw