When you use the Aligner sharpening kit by DMT, you are sure to use a constant angle while sharpening. That is ideal to get your knives back to razor sharpness. The Extra Coarse-stone is a good stone for all coarse sharpening jobs, such as removing rust or sharpening heavier tools such as axes. Always take into account that a diamond sharpening stone has to be made ready for sharpening. Only after 5 to 10 knives the stone works as intended.