While it is technically possible to sharpen a knife with an angle grinder, it is not recommended for most people, especially those without experience using power tools. Angle grinders are powerful and aggressive tools designed for heavy-duty tasks like cutting and grinding metal or masonry.
Using an angle grinder to sharpen a knife requires a high level of skill and control to avoid damaging the knife or injuring yourself. The high-speed rotation of the grinding wheel can easily overheat and ruin the tempering of the blade, leading to a loss of hardness and sharpness. Moreover, the grinder's coarse abrasive can remove excessive amounts of metal quickly, potentially ruining the knife's edge and shape.
Instead, it is safer and more practical to use traditional sharpening tools like whetstones, honing rods, or a sharpening system specifically designed for kitchen knives. These tools allow for better precision and control while sharpening, and they are more forgiving to beginners.
If you are not confident in your ability to sharpen a knife properly, consider taking the knife to a professional knife sharpener or attending a class or workshop on knife sharpening. Properly maintaining the edge of your knives will help prolong their life and ensure safe and effective cutting in the kitchen.