$fa = $preview ? 12 : 1;
$fs = $preview ? 1 : 0.2;

height=168;
diameter=67;
thickness=2.5;

intersection(){
union(){
    difference(){
        cylinder(h=(height+thickness-15),r=diameter/2+thickness,center=true);
        translate([0,0,thickness/2+.1])
            cylinder(h=(height-15+.1),r=diameter/2,center=true);
        translate([0,0,.6])
            difference(){
                cylinder(h=(height-15-1.2),r=diameter/2+thickness-.6,center=true);
                cylinder(h=(height-15-1.0),r=diameter/2+.6,center=true);
            }
    }

    for(i=[-4:1:4]){
        translate([0,0,i*15])
        union(){
            difference(){
                cylinder(h=2, r=diameter/2+thickness,center=true);
                cylinder(h=2.1, r=diameter/2, center=true);
            }
            rotate_extrude()
            translate([diameter/2,0,0])
                scale([.5,1,1])
                    circle(r=1);
        }
    }
}
if($preview){
    translate([0,20,0])
    cube([80,40,200], center=true);
}
}