The Swaging Process Swaged Pipe Spool Dimensions The process of swaging, as performed on the Abbey Etna Rotary Swager, consists of hammering a piece of metal to reduce its diameter without grinding or cutting. Abbey Etna has built what is probably the largest swager of its type-- The 916 machine designed to accommodate 8" O.D. pipe. It is used by Resistoflex at its Bay City, Michigan plant to reduce pipe around a plastic liner. The largest lined pipe, until this machine was developed, was 6".