// --- Parameters ---
base_radius = 55;
wall_height = 20;
thickness = 1.5;
flare_angle = 20;
$fn = 500;

rotate_extrude() {
    offset(r = 0.5)
    offset(delta = -0.5) 
    polygon(points = [
        [0, 0],
        [base_radius, 0],
        [base_radius + wall_height * tan(flare_angle), wall_height],
        [base_radius + wall_height * tan(flare_angle) - (thickness / cos(flare_angle)), wall_height],
        [base_radius - thickness, thickness],
        [0, thickness]
    ]);
}