Whetstones are used for grinding and honing the knife edges. Even the best kitchen knife will lose its initial sharpness over time. They have different degrees, depending on the grain of the stone. A fine-grained whetstone is dense, sharpens less, but allows adjustments in the edge. In contrast, a coarse grain edge removes more material from the cutting edge. The higher the grain reference number, the smaller the grain size.
Sharpeners are safe and easy to use devices. Although a whetstone is the best for sharpening a kitchen knife, a sharpener is faster and perfect for amateur chefs. The sharpeners are not suitable for Japanese knives and serrated blades.
The sharpening steel does not sharpen the knife; with it we can only prepare the edge to cut or, in more technical terms, "maintain the edge". Using other words, with the sharpening steel "we will delay" the sharpening.