use <Threading.scad>

difference() {
 sphere(20,$fn=300);
 translate ([0,0,-10]) {
 cylinder(h=45, r1=5.7, r2=5.7);
 rotate(a=40, v=[1,1,0]) {
        cylinder(h=44, r1=1, r2=1,$fn=20);
    }

 rotate(a=[0,0,135]) {
    rotate(a=35, v=[1,0,0]) {
        cylinder(h=42, r1=1, r2=1,$fn=20);
    }
 }
 rotate(a=[0,0,225]) {
    rotate(a=35, v=[1,0,0]) {
        cylinder(h=42, r1=1, r2=1,$fn=20);
    }
 }
 rotate(a=[0,0,315]) {
    rotate(a=35, v=[1,0,0]) {
        cylinder(h=42, r1=1, r2=1,$fn=20);
    }
 }
 }
 translate ([0,0,10]) {
 threading(pitch = 2, d = 12.9, windings = 7, helices = 1, angle = 60, steps=140, full = false);
 }
}