OpenSCAD $fn=50; difference(){ union(){ difference(){ hull(){ translate([100,0,0]) {cylinder(h=10,r=10);} cylinder(h=10,r=10);} hull(){ translate([100,0,2]) {cylinder(h=10,r=8);} translate([0,0,2]) {cylinder(h=10,r=8);} } } translate([50,0,0]) {cylinder(h=20,r=10);} translate([0,0,-10]) {cylinder(h=12,r=2);} translate([100,0,-10]) {cylinder(h=12,r=2);} } translate([50,0,-1]) {cylinder(h=22,r1=2,r2=5);} } hull(){ translate([-10,-1,0]){cube([2,2,10]);} translate([43,-1,0]){cube([2,2,20]);} } hull(){ translate([57,-1,0]){cube([2,2,20]);} translate([107,-1,0]){cube([2,2,10]);} } translate([0,0,0]) {cylinder(h=10,d=5);} translate([100,0,0]) {cylinder(h=10,d=5);}