include <BOSL2/std.scad>

h = 10;
base_h = 5.5;
d = 28;
t = 2;

$fn = 360;

diff("R") {
    cyl(d=d+2*t, h=h, anchor=BOTTOM);
    tag("R") up(base_h) cyl(d=d, h=h, anchor=BOTTOM);
}