wall_thickness = 1;
holder_floor = 3;
holder_arms_length = 10;
-holder_height = holder_floor + holder_arms_length + (5 / 8) * ball_diameter;
+holder_height = holder_floor + holder_arms_length + (11 / 16) * ball_diameter;
holder_radius = ball_radius + wall_thickness;
holder_diameter = holder_radius * 2;