If you want aid measuring the centerline radius of the existing elbow, it is best to talk to an elbow production professional to ensure you get the ideal measurements and the ideal solution for your requirements. Pipe fitter education, metal fitter training, piping and structural fitter fabricator instruction tips on https://www.malleableiron-pipefitting.com/industry-knowledge/how-to-find-elbow-center-of-pipe.html