screw_head_dia=7.5; width = 19; length = 35; height = 6; $fn = 100; module rdrop(radius, length){ { union() { sphere(radius); translate([0, 0, radius * sin(20)]) cylinder(h = length-radius, r1 = radius * cos(20), r2 = 0); } } } module x() { difference() { /* solid */ scale([1,1,height/width*2]) rotate([90,0,0]) rdrop( width/2, length ); translate([0,0,-500]) cube([1000,1000,1000],center=true); cylinder(h=1000,d=screw_head_dia,center=true); } } x();