Recommendation? Japanese knives and the Work Sharp Ken Onion Sharpener + engineers opinion on whetstone

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Hello everyone, I just made an account on their forum for this question, So I hope you guys can help me out.

Just yesterday I received a KAN Core 8-inch Chef Knife as a gift, and I gotta say I'm thrilled (even though I am aware it's not actually Japanese made, more like Japanese inspired, but that's kinda irrelevant). On the little getting started guide they provide, it says to avoid using a belt sharpening system, as they create convex edges on the blade:

About a month ago I bought a used Ken Onion Work Sharp Sharpener to sharpen the cheap knives I use on a daily basis, and I gotta say, to an inexperienced individual it worked great.

Before purchasing it, I tried my hand at a pebble brand whetstone, and spent quite a few hours trying to get good at it, and maintain a constant angle and pressure and whatnot, but I never really could do it all that well or all that consistently, I would always end up with sections of my knife being sharper than others. It was always odd to me that all the professionals swear by this incredibly artistic system. I am an engineering student, and I can't escape the fact that if whetstone sharpening requires so much hand precision and skill, it can't really be an ideal solution to knife sharpening, which is what drew me into the work sharp system I bought. Is there any actual risk of ruining my new expensive knife on it? I understand that the heat generated by an actual bench grinder or some other high-power grinding tool can ruin the temper on the blade, but the Work Sharp system can spin at a super slow RPM and you are supposed to move the knife through it pretty quickly, I can't imagine it would have enough time to generate enough heat to do any real damage.

What I am more concerned about is altering the geometry. Belt sharpening by its very nature will create a convex edge. Is this a bad thing? will changing the geometry of my knife "ruin it"? From my perspective, I can't see this being any more prone to geometry changing than just being bad at using a whetstone, so I'm not really sure, I'm very new to the knife enthusiast scene, and wanted to make sure I can actually take care of this knife, (and avoid buying more whetstones cause I can't seem to be any good at them)
 
Convex edges are great for kitchen knives. A WorkSharp is nice, but be aware that is can remove metal quickly. This is what they mean by changing the geometry. If you remove a lot of steel, the area behind the edge will get fatter and not cut as well. This means you will need to thin it, which is more time consuming. Also with a belt sander/WorkSharp, you are working a small area and need to keep the blade moving across the belt so you don't create dips/holes in the edge area from overgrinding it. This is what they mean by changing the profile. The convex edge isn't the bad part, it's removing too much or unevenly and making the knife not perform as it should. Even with variable speed belt sander/worksharp, it can still overheat the blade if you aren't careful. Light pressure and keeping the blade moving are important.
 
Another option is to use a jig for the whetstone, used correctly you can eliminate most of the human error and you won't accidentally overheat the edge.
 
Another option is to use a jig for the whetstone, used correctly you can eliminate most of the human error and you won't accidentally overheat the edge.
I've looked around for jig options, and they are all ridiculously over priced unfortunately
 
I can tell you I used a Worksharp Ken Onion on a MAC PRO knife with sucess. I bought it and the handle was too small for me but my wife likes fine.
I sharpen up to the 5000 belt and then I used a leather strop with white compound to polish the edge. You have to pull the guide off to use the strop. Watch the video.
 
I can tell you I used a Worksharp Ken Onion on a MAC PRO knife with sucess. I bought it and the handle was too small for me but my wife likes fine.
I sharpen up to the 5000 belt and then I used a leather strop with white compound to polish the edge. You have to pull the guide off to use the strop. Watch the video.
I didn't even know there was a leather strop, it didn't come with mine, but good to know, thanks
 
It is US made on eBay. It comes with the leather belt and white compound. Make sure you buy the correct length for the KO guide system. They have one for the free hand adapter for the Ken Onion which is a longer length.
 
Convex edges are great for kitchen knives. A WorkSharp is nice, but be aware that is can remove metal quickly. This is what they mean by changing the geometry. If you remove a lot of steel, the area behind the edge will get fatter and not cut as well. This means you will need to thin it, which is more time consuming. Also with a belt sander/WorkSharp, you are working a small area and need to keep the blade moving across the belt so you don't create dips/holes in the edge area from overgrinding it. This is what they mean by changing the profile. The convex edge isn't the bad part, it's removing too much or unevenly and making the knife not perform as it should. Even with variable speed belt sander/worksharp, it can still overheat the blade if you aren't careful. Light pressure and keeping the blade moving are important.
Hmm could you elaborate on what you need by removing the area behind the edge? Is there perhaps a diagram I could look at?
 
These explain it pretty well:

You either need to thin the entire side of the knife, or thin out the area directly behind the edge of the knife. As you sharpen more of the blade away, since the blade tapers, you are getting a fatter area behind the edge as you sharpen since the blade is losing the height.
 
I have never thinned a knife using my Ken Onion sharpener. I have used a Worksharp for around 10 years and the Ken Onion for 3 or so years. I know they say to but my knives cut tomatoes fine and it stays sharp for months. I only have 1 Japanese knife the MAC Pro so my experience is limited but I have not seen a problem. When the handle did not fit me after ordering a MAC Pro, I decided I would not buy any more Japanese knives unless I could feel it in my hand. Luckly the MAC Pro handle fit my wife's small hand and she likes it.

And for them to cut well I sharpen at 15 degrees. I sharpen Henckels 4star, Wusthof Classic, and 1 MAC Pro knives. These are the only kitchen knives I use. I have around 30 probably more when I count what is in the drawers.
 
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I have never thinned a knife using my Ken Onion sharpener. I have used a Worksharp for around 10 years and the Ken Onion for 3 or so years. I know they say to but my knives cut tomatoes fine and it stays sharp for months. I only have 1 Japanese knife the MAC Pro so my experience is limited but I have not seen a problem. When the handle did not fit me after ordering a MAC Pro, I decided I would not buy any more Japanese knives unless I could feel it in my hand. Luckly the MAC Pro handle fit my wife's small hand and she likes it.

And for them to cut well I sharpen at 15 degrees. I sharpen Henckels 4star, Wusthof Classic, and 1 MAC Pro knives. These are the only kitchen knives I use. I have around 30 probably more when I count what is in the drawers.
The geometry benefits of thinning behind the edge are most noticeable with stiffer fruits and vegetables like apples and carrots, tomatoes can be sliced with just about anything that has a good apex.
 
You don't need to hold that tight of an angle to sharpen your knife. Like many engineering students, you might be overthinking things. Ask me how I know. It's very fast to sharpen a knife with a stone in one hand and the knife in the other. There is no way tight angle control is mixed into that method. The slop in this sort of freehand sharpening creates a fairly convex edge.

I am not familiar with the stone you referenced. What grit is it? The Pebbles brand stones don't look too bad, but if you're trying to learn to sharpen on a 1000 grit stone or finer, you're either going to develop a lot of patience or learn to repair windows after you throw the stone through one. I've recently come to believe that many a would be sharpener becomes frustrated by the slow progress they make and gives up.

I also cannot recommend any sanding/grinding belt sharpener for use on knives, as it's easy to remove a lot of material very fast in the wrong place, and its extremely easy to overheat the edge and decrease edge durability and edge holding, even as slow as the Worksharp goes. However, it is more important to get the knife sharp enough to use. An overheated edge doesn't mean anything if its too dull to cut in the first place. So, if the Worksharp is how you can sharpen knives best, then it will work.

I'd recommend a couple of different solutions for stone sharpening. First, make sure you actually have a coarse stone. Something like a Norton Coarse India or something that looks like it's rougher than 220 grit sandpaper, just visually. Second either make a jig to hold the stone vertically or horizontally. If you have an 8" stone and a piece of 2x4 lumber you can set one end of the stone on a work bench and the other propped up on the 2x4. Hold the knife horizontally and make several passes per side. 20 passes per side is where I usually start. Mark your edge with a marker or just pay close attention to where the new scratches show up. Make several passes per side, then switch sides. Repeat until you have a burr form after the passes on each side. Then elevate the angle a little and lighten up the pressure and remove the burr. You can use the same coarse stone for this or switch to a finer one if you have it.
 
I use a Work Shop Mk2 to sharpen the general use knives for my son's restaurant. Zip, zip, done. I do not use it on my good knives at home. Japanese knives get water stones. The others get the Edge Pro system
 
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