If you need enable measuring the centerline radius of an current elbow, it is best to talk to an elbow production professional to make sure you get the correct measurements and the ideal Answer for your requirements. Pipe fitter teaching, metal fitter coaching, piping and structural fitter fabricator instruction tips https://www.malleableiron-pipefitting.com/industry-knowledge/how-to-find-elbow-center-of-pipe.html