inner_radius = 10.75;
radius = 12;

height = 3;
inner_height = 5;

difference() {
    translate([0, 0, -1.5])
        cylinder(r=radius+1.5, h=inner_height+height+1.5-0.02);
    difference() {
        union() {
            translate([0, 0, inner_height-0.01]) cylinder(r=radius, h=height);
            cylinder(r=inner_radius, h=inner_height);
        }
        translate([0, 0, -0.01]) cylinder(r1=inner_radius-4, r2=inner_radius/4, height=inner_height);
    }
}