Square-to-Round (STOR) is a software application to design square-to-circle transformers. Within the construction industry, tradesmen and especially sheet metal workers need to know how to construct a square-to-round. Square-to-rounds are often used to form hoppers, stove chimney hoods and HVAC pipe work systems.
The pro (paid 2gbp ) version can export dxf files. There's no adds, no in-app billing and no lengthy in cloud processing required.
https://play.google.com/store/apps/details?id=uk.co.tyharness.storpro1