If your knife fails the following test even after careful sharpening, it needs to be sharpened: Hold a piece of newspaper with one hand, then cut it with the lightest pressure. The knife must cut smoothly - and not tear - through the paper. How long it is able to do this depends primarily on the cutting surface and your care. But be careful: When sharpening a knife, the cutting edge is rebuilt, which always involves a loss of material on the steel. The inexperienced commonly have ample opportunity to completely wreck a knife during this complicated process.

When working with this device, on the other hand, you get along well even with little practice, because here the precarious determination of the correct grinding angle in each case is given by guide slots: the cutting edge of a dull knife is first rebuilt in two successive operations by means of diamond-studded discs material gently and at an increasingly shallow angle. The final process then removes the grinding burr - via a ceramic wheel - and ensures the actual sharpness. With this third stage, even knives with a serrated edge can be resharpened a few times. You should only treat knives with the two diamond grinding stages of this device when the sharpening steel is no longer able to do anything on them or when they have finally become dull due to lack of care or old age. Then, however, using the Graef diamond sharpener is always a better choice than rushing to the trash can. For regular use, on the other hand, the ceramic honing device is provided.