difference() {
    cylinder(50, 32, 32, center=true);
    cylinder(51, 27, 27, center=true);
}

translate([0, 0, -25]) {
    difference() {
        cylinder(5, 32, 32, center=true);
        cylinder(6, 20, 32, center=true);
    }
}

translate([27, -10, 15]) {
    cube([26, 20, 10]);
}

translate([48, -10, 0]) {
    cube([5, 20, 20]);
}