Gt-12

[gwaii]

figured i'd put together a small 2 into 1 collector,just to show the process.

i start by cutting pieces of tube a little longer than i want the collector to be.in thi case i wanted the finished length to be 3'',so i cut them 3 1/4''.i cut stock from the same size as the smaller pipe,and the number of pieces that the collector inlet will need.

now the fun part...caution-some math is required.

i run two centerlines down the length of the tube,180* apart from each other.i divide the circumfurence of the larger tube size by how many inlet tubes are going into it to get a working measurement.

so in this case,the larger tube is 2'',the circumfurence of which is 6.28''.there are two inlets,so i divide this by two,for 3.14''.
i need to center this measurement on one of the centerlines marked earlier,so i will round this off to 1 9/16'' either side of the line.

these marks are then connected to the opposite end of the centerline on the other side of the tube,marking out a triangular section.

then cut out this triangle.i find a zipcut works well for this.

now you need to open the big end out to the size of the bigger tube.in this case i used a piece of 1 3/4'' tube as a die to hammer out the end.keep in mind that the other end needs to remain at the original size,so don't get too carried away.

after a little bit of dressing on the mating edges(i like to run them over the belt sander,a file would work just as well)the two pieces can be put together.the ends still need to be squared up-this is why i made the initial pieces a bit long,some material will need to be removed.

a view from the other end.after tacking,a little more tapping will get a nice round outlet.

just a little demonstration of how it should fit.to square off the ends,i used tin snips to get it close,then finished it off with the belt sander.

this is the same process regardless of how many inlets or what size outlet.as an example,my secondary collector will be 3 2'' inlets to a 3 1/2'' outlet
so for that i will cut 3 4 1/2'' long pieces of 2'' pipe,my 3 1/2'' circumfurence is 11'',divided by 3 is 3.66''.i'll round this to 3 5/8,so i'll measure 1 13/16'' either side of the centerline.you get the idea,this can be used to easilly make professional looking collectors of any size and any number of inlets.

 

[MountainMike]

I am so lost. On the bright tomorrow I'm going to study each word and picture in detail and learn just one of your many awesome techniques and gain a little knowledge

 

[TheTopher]

Very well explained, mate.

 

[dhinch279]

so basically it all equals "pi". just kidding. But thats a good right up. If it was me, I usually just eyeball it, but its nice to know that there is a formula for that to get exact measurements so you know it will work the first time AND look symmetrical. I just printed this page to put in my toolbox, you never know when you might need it.

 

[COPPERHEAD85]

When I was in the Duct Work biz we called that a pair of pants...lol.
Never crossed my mind to apply it this way.Working with square Duct is a little different than pipe though but the end result is the same I guess.

 

[martin]

I can imagine hundreds of guys are now heading out to their garages or driveways to start building headers for their rigs. here's a tip for the guys that are not happy working with the math or numbers in general. If you use a piece of string to measure the circumference of the pipes you can fold and mark the string into the number of divisions you need instead of dealing with the math. Another thing that was not stressed enough is "THIS IS NOT A FIVE MINUTE JOB". I would also not recommend it as your first welding job.

When you do the finish welding are you going to bolt the flanges to a blank of some sort to prevent warpage?

 

[gwaii]

When I was in the Duct Work biz we called that a pair of pants...lol.
Never crossed my mind to apply it this way.Working with square Duct is a little different than pipe though but the end result is the same I guess.

yup,a 'pair of pants' is exactly what that is known as in the vent biz.i spent a lot of years in the sheet metal(hvac)industry before morphing into general custom fab work,and all the rules for flow and layout are the same whether it's air,exhaust,or whatever flowing through the pipe.

When you do the finish welding are you going to bolt the flanges to a blank of some sort to prevent warpage?

at that point i'll just tack a piece of flatbar or angle to the flanges,then cut it off when done.

 

[gwaii]

so basically it all equals "pi".

that it does

with this sort of stuff,pi is your best freind.in the example above,the working dimention happened to be pi(3.14)simply because the 2'' tube size is 2x3.14 divided by how many inlets(2)for 1x3.14=3.14.

but if you have a typical v8 header with four 1 5/8 tubes going into a 3'' collector,i would do it as such:

3x3.14=9.42
9.42/4=2.35.this is pretty close to 2 3/8(we don't need to be super accurate on these,so i always round the decimal size to a close fractional size for ease of working)half of 2 3/8'' is 1 3/16'',so this is the amount i would measure each side of center for the cutout.
make four of them,and weld them together.if you do careful measuring and welding,you'll have a pro looking collector.

 

[kris97ranger]

i cant believe how much ive missed! for some reason im not getting any emails from this site saying someones posted. but it looks awsome

 

[gwaii]

i cant believe how much ive missed! for some reason im not getting any emails from this site saying someones posted. but it looks awsome

just gotta keep checking,i guess.

theres posts to this thread almost every day....maybe i need to get myself a life





na,i had a life once...it was boring.i'm better off like this

 

[gwaii]

had some e-bay goodies come in today.new taillight lenses and a hood latch.
still waiting on the tach.

 

[COPPERHEAD85]

I love packages from Ebay almost as much as LMC....lol!
If I could score a gig laying out and building duct work again I would jump on it as long as I didnt have to install it.I hated crawling under houses.
By far the hardest thing to lay out was a square to round from scratch.I think I would have a brain hemmorage trying to do that again.

 

[gwaii]

I love packages from Ebay almost as much as LMC....lol!
If I could score a gig laying out and building duct work again I would jump on it as long as I didnt have to install it.I hated crawling under houses.
By far the hardest thing to lay out was a square to round from scratch.I think I would have a brain hemmorage trying to do that again.

i was in commercial/institutional/industrial sheet metal,but the insallation could be just as bad as residential.layout of fittings was one of my favorite things,i was pretty dissappointed when computerised plasma tables started taking over.

you want fun?try laying out 7 segment square-to-round elbows...those aren't in the computer

 

[gwaii]

another little project i was involved with....

i was in charge of the shop fabrication and field installation of this project.

that's me fourth from the right,in the blue hardhat.

 

[COPPERHEAD85]

It figures you would be the one with his hat tilted trying to be cool.....lol!
I never made it up to square to round elbows,I thought they cheated when the switched to duct mate instead of drives and s cleat.
The Plas table was kinda nice though.The last time I ran one was to cut table slats for a Laser,3000 watt Trumph also got to run a 4000 watt.The plasma table went the way of the Trac-Torch which I bet you have ran also.