Clamp-style sharpening tools use a clamp with several holes with predefined angles. The stone is mounted on a rod and is pulled through these holes, so that the angle remains consistent. Another system is the crock stick setup, where two sticks are put into a plastic or wooden base to form a V shape. When the knife is pulled up the V, the angle is held so long as the blade is held perpendicular to the base. Several cutlery manufacturers now offer electric knife sharpeners with multiple stages with at least one grinding stage. These electric sharpeners are typically used in the kitchen but have the ability to sharpen blades such as pocket or tactical knives. The main benefit of using an electric sharpener is speed with many models that can complete the sharpening process in one to two minutes. The disadvantage is that the sharpening angle is fixed so some specialized knives, like a Japanese style Santoku, may need additional attention to sharpen to the ideal angle.
We tend to recommend natural Japanese water stones only to experienced users who are thoroughly familiar with the synthetic Japanese sharpening stones. Natural stones are not to everybody’s taste and there are inevitably many uncertainties with regard to their grit grade, which cannot be determined exactly, their hardness and their suitability for certain types of steel.
Practice holding the knife at a 20 degree angle. Most straight blades need to be sharpened at a 20 degree angle. To find the angle, hold the directly in front of you so it's straight up and down. This is 90 degrees. Tilt the knife halfway towards the table so it's at a 45 degree angle. Tilt the knife halfway again so it's about an inch (2.5 cm) above the table. This should be a 20 degree angle.
There will be a drawer that extends into the mechanism under the abrasives. Any detritus from the sharpening process drops into this drawer. Exactly where the drawer is located will differ from sharpener to sharpener but it shouldn’t be hard to find. Remove the drawer flick any material into the wastebasket and then wipe out the drawer with a damp cloth or tissue. You may want to use work gloves and goggles to protect your hands and eyes from any loose metal shavings. Once the drawer is clean and dry replace it. The exact means by which the sharpening mechanism itself is cleaned will vary from manufacturer to manufacturer. Consult your owners guide for specific details. Make sure you don’t introduce any grease or other lubricants into the sharpener unless specifically directed to do so by the owner’s manual. Also, the outside of the sharpener should come perfectly clean with just a damp cloth. Avoid using commercial cleaners or abrasives of any kind.
The composition of the stone affects the sharpness of the blade (a finer grain, usually, though not always, produces sharper blades), as does the composition of the blade (some metals take and keep an edge better than others). For example, Western kitchen knives are usually made of softer steel and take an edge angle of 20–22°, while East Asian kitchen knives are traditionally of harder steel and take an edge angle of 15–18°. The Western-style kitchen knives are generally in the range of 52–58 on the Rockwell scale, which denotes the relative hardness of a material.
Oil Stones differ from water stones in that they require the use of honing oil to float the swarf (metal particles). Also, these stones are commonly made from one of three different materials consisting of Novaculite, Aluminum Oxide (Corundum), or Silicon Carbide (Carborundum) and they all use oil to lubricate the stone and suspend the swarf in order to prevent the stone from becoming clogged. Also, while Novaculite and Coticule are the most traditional types of oil stones, there are also synthetic oil stones made by the Norton abrasives company called “India Oil Stones”.
Selecting the right sharpening angle is the next step in sharpening. For more detailed instructions on selecting the right angle, try reading this article. Regardless of the method of sharpening, a appropriate angle should be selected. This angle doesn't need to be exact but following some general guidelines is a good idea. Most knife manufacturers recommend a roughly 20 degree angle. Depending on the use of your knife, you can move up or down from that angle. A fillet or slicing knife is never used on anything hard so an angle a few degrees less will produce a sharper edge. On the other hand, a survival knife with various uses can benefit from a more durable edge a few degrees larger.