Currently have a Misono ux10 which has a 70/30 bevel.
How would i go about sharpening such a blade? Would like to keep factory angles/bevel, different angles on each side or same angle less strokes on one side? :unsure:
[quote quote=“ChefsEdges” post=23124]Currently have a Misono ux10 which has a 70/30 bevel.
How would i go about sharpening such a blade? Would like to keep factory angles/bevel, different angles on each side or same angle less strokes on one side? :unsure:[/quote]
Unless you have the LAA you really can’t get down low enough on the 30 side. The video below covers what I did on the same knife. This was the first time I tried asymmetry on the WE, and have debated whether or not I should just go ahead and delete the video to save myself some embarrassment. The only reason I have not delete it is because A) I want to document my overall progress (WE & freehand sharpening) and B ) it’s hard to come across videos of ANYONE sharpening kitchen knives, especially Japanese with asymmetrical bevels.
Since I posted this video I have been hitting the books, so to speak, learning about the geometry and functional differences of these strange edges Also, and probably most importantly, I’ve stepped back from my WE and have really getting my hands dirty on the wet stones… And scared 
Do it at 15K per side the 70/30 relates to the proportions so the bevel should be just over twice as wide on the right hand side as the left .I would do the left hand side first then the right . then cut through a melon & see that it does not steer.
So 15 degree both sides and just do less strokes on the side closest to you as your using the knife. :unsure:
I knew Leo’s reply would throw another wrench in your system. But, yes, it’s safer to listen to him.
His reply opens up a can of worms. And that’s NOT a bad thing. From what I gather here and from a number of other sources, there seems to be two schools of thought when it comes to asymmetry.
- x/y represents each bevel’s angle as a proportion of the total inclusive angle.
- x/y relates to each bevel’s width as a proportion of its own.
The first assumes x/y is dependent upon the total inclusive angle since the proportion of each angle is confined by the total inclusive angle, while the second assumes x/y is independent upon the total inclusive angle already set at a 50/50 proportion. With the latter, if you want a 30° inclusive cutting edge you’d sharpen at 15° on the left side ad 15° on the right side while lengthening one of the bevel’s width more so on one side to get a certain (70/30 in your case) proportion within the overall surface area of the inclusive angle. Taking the first route mentioned is done so by considering a certain proportion as it relates to the geometry of the cutting edge rather than the surface area of the cutting edge.
To be honest, don’t get caught up in this just yet. Sharpen the knife you have by doing what Leo says… You can come back to this whole other world at a later date 
… Splitting hairs.
That’s not splitting hairs at all, Steven. When people talk about uneven bevels, it’s often not clear what they mean. Your numbers 1 and 2 are exactly what it’s about.
[quote quote=“KnifeKnerdAtX” post=23149]From what I gather here and from a number of other sources, there seems to be two schools of thought when it comes to asymmetry.
- x/y represents each bevel’s angle as a proportion of the total inclusive angle.
- x/y relates to each bevel’s width as a proportion of its own.
[/quote]
To add some numbers in here, given a 30 degree included angle:
- x/y represents each bevel’s angle as a proportion of the total inclusive angle - x=21° and y=9°
- x/y relates to each bevel’s width as a proportion of its own - x=15° and y=15° where x=7 strokes to y=3 strokes.
[quote quote=“wickededge” post=23157][quote quote=“KnifeKnerdAtX” post=23149]From what I gather here and from a number of other sources, there seems to be two schools of thought when it comes to asymmetry.
- x/y represents each bevel’s angle as a proportion of the total inclusive angle.
- x/y relates to each bevel’s width as a proportion of its own.
[/quote]
To add some numbers in here, given a 30 degree included angle:
- x/y represents each bevel’s angle as a proportion of the total inclusive angle - x=21° and y=9°
- x/y relates to each bevel’s width as a proportion of its own - x=15° and y=15° where x=7 strokes to y=3 strokes.[/quote]
Exactly. I meant to touch on the number of strokes as you alternate from side to side. So thanks for adding that in, Clay!
With the Misono UX10 I sharpened I obviously chose to take the route of #1, which is why I had to alter the 70/30 (21dps/9dps) to 80/20 (18dps/12dps). As I mentioned in the video and in reply to your post, reaching 9dps was impossible without the LAA.
Steven, I don’t know this particular knife, but I interpreted Leo’s post as if you should use method 2. Is there a reason you chose method 1?
Let me preface this by stating: Leo’s extremely more knowledgeable than I am. Heck, I really only know what I think I know. That said, I’m just trying to explain it in a way that stands out to me…
In terms our day-to-day discussions regarding edges that are by “default” 50/50, when, if EVER, do we refer to the width of a bevel rather than the geometry of the bevel? If 50/50 assumes a symmetrical inclusive edge geometry, when we say, “reprofiled at 17dps” do we EVER mention the actual width of the bevels when considering this 50/50 geometry? I’d argue to say that the answer is more of then than not, “No.”
So, why is it only when we shift from that 50/50 to, say, 70/30, that automatically we now are on the subject of something that isn’t even discussed at the so-called equilibrium known as 50/50?
50/50 = symmetrical geometry
70/30 = asymmetrical geometry
I highlighted geometry, not because I’m trying to be arrogant, but because that’s the point I’m trying to make in order to effectively answer the question as it relates to my current understanding.
I believe, If anything, option #2 (3 on the x-hand side, 7 on the y-hand side) is in fact a natural method of maintaining the asymmetry created by option #1. A byproduct essentially…
Hey Steven, you’re completely right.in your first post above this one That’s what this makes this topic so confusing.
I dont’t think I agree with your second post above this one, since we’re really talking different angles. That’s something different than grinding longer at the same angle.
I’ve been wanting to make a point on the asymmetry issue. While the number of strokes is a good “rule of thumb” approach, users should be aware that a stroke taken on a narrow bevel will remove more metal than a stroke taken on a wide bevel. This means that if you start with an edge on which one side is 3/7 as wide as the other (30/70) and then take fifteen strokes on the 30 side and 35 strokes on the 70 side, the chances are that the edge will no longer be 30/70, probably more like 40/60. Continuing on that path will increase the ratio.
The amount of metal you remove with each stroke is dependent on a couple of variables other than grit.
First is the number of inches of abrasive that passes over a given point with each stroke. When you take a diagonal stroke, each point along the edge is touched by a line of abrasives - usually a diagonal line drawn across the face of the stone. The longer the blade, the shallower the swipe and the shorter the diagonal line. A simple length-wise stroke will expose each point along the edge to only the width of the stone - about 3/4". The shorter the blade, the longer the diagonal line. A straight vertical stroke will see the longest line of abrasive passing over a specific point, limited only by the length of the stone and the stroke length - maybe about 3-1/2", but about four times as much as the horizontal stroke.
Second is the amount of pressure applied against the substrate by the abrasive. The more pressure applied, the more metal removed per stroke. Assuming the same amount of hand pressure with each stroke, a very narrow bevel face will see more pressure per square inch than a wide bevel facet. It’s also important to understand that the amount of facet area to which pressure is applied decreases where the edge is convex. The more convex the contour of the edge, the higher the pressure applied to the contact point and the more quickly metal is removed. Consider that with a straight edge, the contact patch area is the width of of the bevel times the width of the stone. As the edge becomes convex, the contact patch becomes shorter, thereby increasing the pressure applied by the abrasive.
It should also be understood that the pressure applied to the contact point is a function of where the pressure is applied to the stone. Given an equal pressure applied by your hand with each stroke, the pressure at the contact point increases as the point of force application rises along the slide-rod. It’s a simple lever situation. The distance from fulcrum to the force application point and the distance from fulcrum to the contact point varies through the stroke. Therefor the pressure at the contact point varies throughout the stroke. Where the hand pressure point rises above the edge contact point, the amount of pressure applied to the edge is multiplied by the ratio of the distances.
This all means that strokes taken on the 30-side will likely remove almost twice as much metal at any given point as strokes taken with the same stone, same pressure on the 70-side. Suggesting that as you approach the 30/70 ideal proportion, you should proceed carefully.
Didja ever notice that it takes longer to reach an apex near the heel of a blade?
This is another Tom Meyer hypothesis, written at 3:00 AM. I’m very interested for someone to prove me wrong - or right. Either way.
[quote quote=“mark76” post=23162]Hey Steven, you’re completely right.in your first post above this one That’s what this makes this topic so confusing.
I dont’t think I agree with your second post above this one, since we’re really talking different angles. That’s something different than grinding longer at the same angle.[/quote]
Ugh. So confusing!
What I forgot to include in the second post was the two bevel angles would be matched prior to the alternating 3 x-side/7 y-side passes…
Excellent point TC!!!
Chefs edges essentially you are right less strokes n the left still go for a burr then more on the right I think eyes & fingers are your best guide not sure how I would do it on the WE they are nice slender knives.so it should not take much to do.
I think it’s time to start a whole new category on the forum covering asymmetry…
If a thread were created, under what board category do you guys think is appropriate?
- Thoughts/Theories/Science?
- Advanced Techniques?
- Tips for Specific Grinds?
- Task Specific Sharpening (cooking)?
Thanks for thinking with us. I’d say Advanced Techniques. But I promise that if you post it under any of these other categories, I won’t move it.
Awesome, thanks for the support Mark!
In terms of a title, I’m thinking something along the lines of A Primer on Asymmetry? And possibly a Wiki page with a bunch of compiled information and links to additional resources?
A primer on asymmetry would be awesome!