Tired of turning items too quickly or too slowly? Let Pi be your guide! The ratio of the diameter of an item to 3.14 determines the optimal speed at which the inches go by the cutter - the larger the Tired of turning items too quickly or too slowly? Let Pi be your guide! The ratio of the diameter of an item to 3.14 determines the optimal speed at which the inches go by the cutter - the larger the item, the slower you should turn it!