The procedure for the Eccentric and Concentric are near identical. The only real difference comes into the fact that the Eccentric branch if off center. If you remember back when we divided up the half circle for the concentric, we could get away with only laying out half because it was a mirror image. The Eccentric is off center and to show the details of where the lines intersect, we will divide up the entire circle.
Let get started by drawing the end view of Header and Branch. You will notice that the Branch in off of the center line of the header. This off set will be determined by layout needed to make up this fitting and may vary depending on what the situation dictates.
Now we will draw the half circle on end of branch and extend out the height of branch and draw the stretch-out. You will have to verify size of pipe or refer to chart to find total circumference.
Greens lines are to show the extension of branch to develop the stretch-out.
Now we can divide up the stretch-out into 16 equal spaces and divide the half circle up as well. Note: Since this is an eccentric branch and it is not on center. We have to divide up the entire half circle.
Now we can transfer lines from end view to the stretch-out and number match them and place out tick marks. Remember to number each line as well.
Now we can draw our curved line between tick marks and remove transfer lines.
Remove the non-essential lines and the template is ready to use.