radius = 8.25;
wall = 6;
len = 30;

difference() {
    union() {
        hull() {
            rotate([0,0,30]) translate([wall,0,0]) rotate([0,90,0]) cylinder(r=radius+wall,h=len+wall*2);
            rotate([0,0,-30]) translate([wall,0,0]) rotate([0,90,0]) cylinder(r=radius+wall,h=len+wall*2);
            translate([0,0,-radius/2-wall]) cylinder(r=radius+wall,h=radius+wall*2);
        }
        cylinder(r=radius+wall,h=len);
    }
    rotate([0,0,30]) translate([wall*2.4,0,0]) rotate([0,90,0]) cylinder(r=radius,h=len+wall*2);
    rotate([0,0,-30]) translate([wall*2.4,0,0]) rotate([0,90,0]) cylinder(r=radius,h=len+wall*2);
    translate([0,0,-radius/2]) cylinder(r=radius,h=len+wall*2);
}