difference() {
  hull() {
    translate([26,9,0])
    cylinder(h=9, r=10, center=true);
    translate([6,9,0])
    cylinder(h=9, r=15, center=true);
  }  
  hull() {
    translate([26,9,0])
    cylinder(h=12, r=4, center=true);
    translate([6,9,0])
    cylinder(h=12, r=8, center=true);
  }  
}