How to Make a Ducting Elbow

Sometimes I don't understand why they can't calculate how to make a ducting elbow, and this is really happen in our workshop. And for this one I think this is one of the basic knowledge that every Fitter has to know. And because of that, now Piping and Fabrication will post about How to Make Ducting Elbow and how to calculate it (shown in the picture below).

To find out the Radius of a Long Radius Elbow, this is how to do it. Radius = 1 1/2 x Nominal Size, and that's really simple when we want to learn. And from that calculation we know what is the requirements for the materials, and how many plate we will use to make a ducting elbow.

I think may be this post will enough to them know how to make a Ducting Elbow, and hope they will learn much about Piping.