An important but often confusing area of sharpening is knowing when you're done with one stone and ready for the next finer grit. On coarse stones it is very easy. When you sharpen one side you will notice a burr forming on the opposite side of the edge. This burr is hard to see but is easy to feel. Very carefully feel for the burr by gently running your hand from the spine to the edge. (Do not run your finger along the knife edge from heel to tip, that's only asking for trouble!) A burr is formed when your stone removes material directly at the edge. The burr will move from one side of your knife to another as you alternate sharpening sides. Make sure you have felt the burr jump between both sides before you move on to the next finer stone. That will ensure that you have sharpened both sides effectively. The finer grits are done the same way but the burr is much smaller. On the finest grits you may not be able to notice the burr at all. Testing the knife sharpness will tell you when you're done. (Learn how you can test to see if your knife is sharp.)
When starting out sharpening, it won’t be long before you hear about the “toothy” vs “polished” edge. It will suffice to know that a 1k stone is going to give you an edge that will perform beautifully as will a knife finished at 5k. There is a belief that a knife that has a highly polished finish, 5k and up will be so polished that it’s toothy goodness will be erased. This knife will not bite into the skin of a tomato for example because the edge is too polished, it will slide over the top. This is not always true, if the knife has been sharpened well, i.e. if Side A and Side B of the blade meet precisely at the Apex of the knife, that edge will slide into a tomato quite beautifully. I have seen many brand new Japanese knives with highly polished 8k edges that no tomato skin can stand up to.
However, due to limited natural deposits and extensive quarrying over the centuries, true, high quality, Japanese water stones are now few and far between and are very expensive. Thus, various companies are now producing synthetic Japanese Water Stones which generally have a more consistent composition and grit size than natural stones as well as often begin somewhat harder and thus, lasting a bit longer; not to mention being cheaper to purchase.
One thing about this stone is that it is very "thirsty." I had a cup of water close by just to add a little water periodically when it felt like it was scraping a little too aggressively. Also, be sure to do as the instructions say and use different parts of the sharpening surface. I wasn't paying attention the first few minutes, and apparently I would end each sharpening pass in the exact same spot, creating a very very small notch on the edge of the stone. So I turned the stone around and made sure to vary the ending spot, and it seemed to buff out that little notch very quickly. My knife is now incredibly sharp--it seems to glide through material rather than "cut" it. I know some people would continue to go even higher with the grit, but for my purposes this whetstone is just perfect. I'll be tackling the kitchen knives next!
Finally, when you learn how to sharpen a pocket knife becomes reality, you'll ultimately see the difference in your blade. Every sportsman and kitchen guru should learn how to sharpen a pocket-knife the proper way without "nicking it" or "shaving the edges" off too much you end up with a short and stout blade. Consequently, selecting the proper pocket-knife sharpener is important so learning the in's and out's of how to sharpen a pocket-knife before and after using it is all in the practice as well as in the sharpener itself.
Table mounted device – Typically the manual powered table mounted sharpener looks virtually identical to the electric powered sharpener with a slot for each stage. Where they differ is that each slot in the manual powered sharpener has only one groove and you pull the blade through this groove toward you to sharpen the blade. Once the blade is sufficiently sharp you place it in the honing groove to refine the edge and pull it toward you again several times. If there is a third, cleaning, stage you repeat the process for that stage as well.
Japanese water stones – both natural and synthetic – are known for their superior sharpening performance, not only for Japanese tools, but also on their Western equivalents. The loosely bonded abrasive grit is washed out very quickly, as it blunts during the sharpening process; this exposes new, sharp, particles that can get to work on the blade. Water stones are lubricated only with water! Never use oil!
Historically, there are three broad grades of Japanese sharpening stones: the ara-to, or "rough stone", the naka-to or "middle/medium stone" and the shiage-to or "finishing stone". There is a fourth type of stone, the nagura, which is not used directly. Rather, it is used to form a cutting slurry on the shiage-to, which is often too hard to create the necessary slurry. Converting these names to absolute grit size is difficult as the classes are broad and natural stones have no inherent "grit number". As an indication, ara-to is probably (using a non-Japanese system of grading grit size) 500–1000 grit. The naka-to is probably 3000–5000 grit and the shiage-to is likely 7000–10000 grit. Current synthetic grit values range from extremely coarse, such as 120 grit, through extremely fine, such as 30,000 grit (less than half a micrometer abrasive particle size).
This wedge ends up short of a "point" to a much larger degree than the picture would indicate. The metal stops short, but then there is black non-slide "tape" applied to one side, and white "slide" tape applied to the other side, which makes the wedge even thicker than it appears in the photo, which means that in practice the end of wedge is even more truncated. So I have a hard time supporting my knives accurately on this wedge while sliding them down into contact with my stones. Prior to buying this wedge I just used a wooden wedge I cut off of a 3" by 3" post using a miter saw, said wedgewhich has a much less truncated end. That wooden wedge unfortunately absorbs water from my Japanese Waterstones. But I will try spraying polyurethane on that wooden wedge to help waterproof itand try again. If that doesn't work I will try to find a 3" by 3" plastic trim board somewhere and cut a wedge off the end of that. Note that you can buy 20 degree plastic wedges, but this is the first one I have found that does 15 degrees (nominal.) Note that Amazon also has the Blue AngleGuide set of wedges, but they are very small https://www.amazon.com/Angle-Guides-Sharpening-Knife-Stone/dp/B01N4QMO7U/ref=sr_1_4?ie=UTF8&qid=1499301705&sr=8-4&keywords=sharpening+angle+guide
However, it should also be noted that “water stones” are generally significantly softer than oil stones and thus, water stones generally cut faster than oil stones but, they also have to be flattened more often that oil stones do. Furthermore, it should be noted that some water stones must be soaked in water for several hours prior to use whereas, others are of the “splash and sharpen” variety and thus, they only need to be soaked for a few minutes before use and then wetted down occasionally during sharpening process. Diamond hones on the other hand are more durable than either water stones or oil stones and, because they generally have a more coarse grit, they cut faster than natural whetstones. Plus, due to their construction, they never need truing and, in fact, coarse diamond hones are often used to flatten both natural and synthetic whetstones.
J. Kenji López-Alt is the Chief Culinary Advisor of Serious Eats, and author of the James Beard Award-nominated column The Food Lab, where he unravels the science of home cooking. A restaurant-trained chef and former Editor at Cook's Illustrated magazine, his first book, The Food Lab: Better Home Cooking Through Science is a New York Times Best-Seller, the recipient of a James Beard Award, and was named Cookbook of the Year in 2015 by the International Association of Culinary Professionals.