$screw_offset = 0; // 26
$ptfe_hole_diameter = 4.4; // 4.1

difference() {
    union() {
        box1();
        
        translate([0, 0, 10])
        rotate([90, 0, 0])
        torus(i=7, o=15, xs=0.4, ys=1.5, $fn=100);
    }
    
    translate([0, $screw_offset, 3.70])
    cube([5.6, 3.235, 2.61], center=true);
    
    translate([0, $screw_offset, 3.70])
    rotate([0, 0, 60])
    cube([5.6, 3.235, 2.61], center=true);
    
    translate([0, $screw_offset, 3.70])
    rotate([0, 0, -60])
    cube([5.6, 3.235, 2.61], center=true);
    
    translate([0, $screw_offset, 0])
    cylinder(h=10, d=3.2, center=true, $fn=100);
    
    translate([0, $screw_offset, -4.5])
    cylinder(h=1.01, d=4.4, center=true, $fn=100);
}


module box1() {
    hull() {
        for (x = [-8, 8]) {
            for (y = [-4, 4]) {
                for (z = [-3, 3]) {
                    translate([x, y, z])
                    sphere(d=4, $fn=100);
                }
            }
        }
    }
}

module torus(i, o, xs=1.0, ys=1.0) {
    r = (o - i) / 2;

    rotate_extrude()
    translate([i + r, 0, 0])
    scale([xs, ys, 1.0])
    circle(r);
}