... or thickwall tube).3. screw the expander head on expander.4. put the end of tube on expander head.5. tighten ... tube.3. expander segments are made of high-quality hardened steel.4. For inch:3/8",1/2",5/8",3 ... /4",7/8",1",1-1/8" O.D. Tubing.5. ...