pipe layout

first, sorry i posted this in "pro tips and articals" i hit the wrong area to post in.... so here it goes again. i need help making a conical reducer from 2.5" into 2". im trying to lay it out on paper first so i have a template. i got my circumfrence layed out for both diameters, and connected with a distance of 2.5". only thing is when i cut it out and fold it up my ends dont match and arent straight. ill post pics of what im trying to do here in a bit.
the small line is the circumfernce of the 2" pipe and the big is the C of the 2.5.... but like i said, when i fold it in, it isnt straight...... but its a great side view of what i want..
http://i1143.photobucket.com/albums/...t/IMG_0157.jpg

Your template should look like a doughnut with a bite out of it, you will need to triangulate to find the taper.

Draw an extended line on both tapered sides of you pattern, where they intersect will be the center point of your doughnut. the distance from the intersection/center point to the angled cut on the bottom right of your drawing will be the smaller radius arc on the doughnut, the distance from the center point to the angled cut on your pattern on the lower left will be the larger arc radius on the doughnut.

Edit: I see you already converted the diameter to circumference. Your side view drawing will need to be diameter to do the layouts.

There is a difference between Chord length and ARC length, to understand this, take a piece of paper, make a cone out of it, then flatten the cone, then cut two parallel cuts on the flattened cone as a trim and then unfold it, you will see the Arc and the chord, and you will have your reducer. But it won't look like what you have drawn, it will be curved.

When you fold it back up it will be your cone, you had the right idea but you needed to have the circumerence drawn in an arc, you have it drawn as a chord..

Ya i now relize that it doesent look like a side view, the other one i tried did though, thanks for the help, after a little though i relized it needed the donut look, back to the drawing board

what thickness is the pipe? Is there a reason you couldn't shrink and stretch the ends of the pipe to make them fit? (i.e. get a dolly and shrink the end of the bigger pipe in, and stretch the end of the smaller pipe out to make them fit each other? the bigger pipe will have what looks like a partial dome on the top, and the smaller pipe will look like it has a small trumpet bell on the end of it)