//Disable $fn and $fa, do not change these $fn=0; $fa=0.01; $fs=0.5; top_outer=20.4; top_inner=19; top_length2=15; top_length=10; bottom_outer=14.4; bottom_inner=12; bottom_length=7; difference() { union() { translate([0,0,top_length-top_length2])cylinder(top_length2,d=top_outer); translate([0,0,top_length-top_length2-bottom_length]) cylinder(bottom_length,d=bottom_outer); } cylinder(top_length,d=top_inner); translate([0,0,top_length-top_length2-bottom_length]) cylinder(bottom_length+top_length2-top_length,d=bottom_inner); translate([0,0,top_length-top_length2]) cylinder(top_length2-top_length,d1=bottom_inner,d2=top_inner); }