$fn=30;

SWg=25;
Hg=10;

SWk=10;

Da=70;

H=25;

radius=2;

difference() {
  union() {
    cylinder(r=SWg/sqrt(3), h=H, center=false, $fn=6);
    translate([0,0,radius]) union() {
      hull() rotate_extrude($fn=90) translate([Da/2-radius,0]) circle(r=radius);
      cylinder(d=Da, h=H-Hg, $fn=90);
    }
    for(i=[0:360/16:359]) rotate([0,0,i]) translate([Da/2,0,4]) hull() {
      sphere(d=4);
      translate([0,0,10]) sphere(d=4);
    }
  }
  cylinder(r=SWk/sqrt(3), h=3*H, center=true, $fn=6);
  translate([Da*4/5/2,0,0]) cylinder(d=5, h=3*H, center=true);
}