You're just going to have to go into the throat of that 90 a little at a time till it comes out good on a level, my friend....

I have never done it but believe it can be layed out using parallel line development. If I get a chance I'll make a drawing. The only thing different is the fact that the ordinates for the ell will be transfered to the point of intersection by swinging an arc from the center of the radius of the ell.

Draw an end view of the header showing the header and the ell. Draw a projection of the,end of the ell. Divide that into 8 or 16 parts. Then from the center if the ell, draw an arc from each ordinate to the point of intersection on the header. You then have something to start with.

Transferring the lengths for each ordinate would be a pain I think.

Of course some hands can probably just rough it in little by little.

This is from my phone so may have some spelling and other errors. its a pain to edit after something is typed.

Gerald

EDIT

Here is what I THINK you are doing.



I will try to show what I was suggesting for the layout.

Hello argoncowboy, does your challenge look anything like this? This would be a "to size, direct measure" method for coming up with the necessary pattern measurements to saddle in on a ninety degree Ell. The pink outline would be how the end of the pipe might look for this sort of fit-up. If it was oriented any other way you would just change the location and angle of the centerline of the saddling pipe and then intersect the lines from that half circle division back to the ones on the Ell. For the size of the pipe you are talking about you would likely want to use quite a few more dividing lines to give your pattern better accuracy. Hope this makes some sense. Best regards, Allan

EDIT: This other picture that I have added now is probably what you were talking about....., I'll bet. After re-reading your original post I realized what you were trying to say and I was too thick to understand. Now if that is it you definitely have a challenge on your hands as far as a pattern or an "accurate layout" goes. Unfortunately, if I tried to get accross how I might go about that particular layout challenge I'd probably confuse myself and anyone else as well. I'll be interested to see if you have any others to elaborate more and give you pointers or direction. Good luck and best regards, Allan

Hello again argoncowboy, if your fit-up is similar to what Gerald drew and I included in my second image could you convince the engineer to alter his/her train of thought? Is there an issue with clearance or closed quarters where this is being put into service? If not, you may wish to ask him to allow you to use a short length of straight pipe with a saddle on one end of it that you could weld onto the Ell and then fit and weld to the header. Just throwing out some suggestions. Good luck and best regards, Allan

Based on what I think you are doing, this is what I was talking about.



Keep in mind that I feel sourdough has a great deal more experience with this and may have the best method however you may be able to combine the two methods to reduce some time.

For me to lay this out in real life I would have to divide the ell into the 16 equal sections as shown, and transfer the dimensions based upon the full scale drawing. I would suggest your own drawing since I fit this to fit OD to OD and I think that may throw things off.

I hope it helps and if not, I hope it doesn't confuse things even more.

Gerald Austin
Iuka MS
www.weldingdata.com