You need to check the rotational direction of the machine before mounting a blade, and there is a directional arrow on each side of our blades, to ensure that they are mounted correctly. Each piece of diamond grit in the segments can be seen as a shooting star, indicating the direction of travel of the blade. If you carefully run your finger around the circumference of the blade, one way is smooth and the other rough. The rough finish on the circumference of the blade indicates the rotational direction of the blade.