I think swaging. The ovals I wanted to use are like the ones from murray's, copper Nicropress ovals. But the discription says they are swaged on using the appropriate sized too. I was going to use a swaging tool like the one in murray's, the 19" two handled type. I noticed they do have a bolt together type swage it tool for nicropress sleeves. I sure would like to know the technical differences of the two.