Sharpening stones are either round or rectangular, and are usually one-half-inch thick.
Whetstone and the carborundum stone are the two most popular sharpening stones.
Whetstones are made of silicone dioxide minerals. They are mined and prepared to become high-grade stones. Carborundum stones are abrasive materials made of silicon carbide.
Sharpening steels have elliptical steel shafts and long, fine-textured grinding surfaces.
The knife blade is drawn in an arcing motion across the grinding surface.
Manual knife sharpeners
Manual knife sharpeners (also called manual countertop knife sharpeners) are often considered to be more efficient than sharpening steels. Most models use tungsten carbide or diamond-coated abrasive grinding stones and heavy-duty ceramic wheels.
Most manual knife sharpeners are ideal for straight and serrated knife blades. The knife is drawn lightly across the sharpening stone at a consistent preset angle. Manual countertop knife sharpeners come in right-hand and left-hand models.
Electric knife sharpeners
Electric knife sharpeners (also called electrical countertop knife sharpeners) operate automatically. They are usually electricity- or battery-powered. They are ideal for sharpening frequently-used knives.
Electric knife sharpeners are generally easy to operate but do not offer the same control level as manual knife sharpeners. Most models can sharpen straight and serrated knife blades. Most electrical countertop knife sharpeners have internal spinning wheels that grind metal blades aggressively.