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New view on Sharpening
In another post on here I commented that the finer the grit, the more exact each stroke needs to be. I now believe that I was wrong. I'm going to attempt to explain why I am now of that belief. It all goes back to my experience with convex edges and post I have recently read about Edge Pros and other blade holding devices.
For 2 years prior to purchasing the Shaptons, I was into convex edges. Everything I had in the house had a convex edge on it, kitchen knives to pocket knives. I sharpened them with sand paper and strops with compounds. It is a very efficient and effective way of sharpening. That was my preferred method, but many people like to use stones for convex sharpening. They rock the blade while they are making each stroke. By doing so, they are honing the entire bevel. The key being, they are consistently honing the apex.
With an Edge Pro, you can hone a completely flat bevel all the while honing the apex on each stroke. While this is efficient, it is not necessary that the bevel be completely flat. What is necessary is that the apex be refined with the stone you are using before moving to a finer grit.
When free hand sharpening, you will never make the same stroke twice. Therefore, you will have a convex edge, however slight that may be. The key here is the same as before. You must refine the apex before moving on.
I'm going to stop here and come back later and add to it, as it is incomplete. Jack, I know you have an opinion. Feel free to go ahead and comment on what I have said so far. We'll make a nice conversation with it.
Replies to This Discussion
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Permalink Reply by Jack Haskins, Jr. on
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I think the finer the grit is the more accurate each stroke needs to be. You are correct in that no two strokes can be repeated exactly when free hand sharpening. This is a fact that is not argued by anyone who sharpens free hand. I think Ben Dale (EP inventor) said that the best free hand sharpeners can't keep the angle more consistant that +/- one degree. So eveyone reading this thread hopefully will accept that free hand skill is never goihng to be perfect even if they haven't experienced it. I can see your point on sharpening convex edges and the fact that we normally hit the apex on every stroke with the exception of when we miss because of normal free hand inaccuracy. The theory of how creating convex edges and the opinion about finer grit stones requiring more accuracy is something I'm going to need to think about I think. So for now let's get away from the issue of convex edges and focus on accuracy needed with different grit stones. The first thing that made me think the higher grit stones required more skill is the fact that most of my life I owned two Arkansas stones. A medium and a fine grit. I could get a really great edge with the medium stone. I could shave arm hair by using 2 or 3 strokes to get a bald spot. Right now I consider this sharpness level the beginning of calling an edge sharp. But when I would try to get the edge sharper by using the fine grit stone it either made no difference at all or it made the edge duller. So, I just quit using the fine grit stone. My edges were sharp enough to get me through the day. Now that I have been working hard and practicing a lot to improve my ability I can get very good results with stones of a much higher grit than the fine grit Arkansas stone. I could only assume my skill getting better made it possible to get improved edges with higher grit stones. This also held true with a Spyderco UF stone. I bought it and it didn't do what I thought it would for my edges so I sold it to help fund a Shapton glass stone (2k). About a year later I bought the Spyderco UF stone again. Now I am getting GREAT edges with that stone. Again, I'm assuming my skill improvement is what makes this happen. While I am only assuming this I believed it from the start of my improvement. But recently I stumbled onto something that I believe shows why the belief that higher grti stones perform better when the person is more skilled. The evidence comes from using the EP. The EP controls the angle almost 100% so free hand inaccuracy is no longer a factor. This will be more clear to people who have used an EP and especially if they use the drill bit stop collar to adjust the angle when changing stones. The collar keeps the angle the same when changing stones of different thicknesses. However, the collar is not 100% accurate but to understand why requires an extensive understanding of geometry. There is a report an expert in geometry wrote about the Edge Pro and the Wicked Edge sharpening systems. One section covers the inaccuracy ofd the stop collar. What makes me trust this report is the fact that I had already known that the collar was not always 100% accurate. I'm just saying all that to kind of reinforce my opinion. I'll try to explain what I had already noticed so it is understandable. Here goes. The EP creates FLAT bevels. When changing to a stone of different thickness due to wear the angle is changed at the point of contact of edge bevel and stone. Using the collar is the easiest and fastest say to adjust for this. I believe the report said the inaccuracy of using the colar results in a .088 degree error. This is a VERY TINY difference. When I set the edge bevel at 15 degrees using a 500 grit stone the bevel is flat and the angle is consistant. When I change stones and use the collar to addjust angle and am now using a 1k stone the angle now is .088 degrees off. But, the 1k stone is coarse enough to remove enough steel in just one stroke that it creates a new angle. The change in angle is NOTHING regarding performance so it doesn't matter. So through the progression I use a 2k, 4k, 8k. When changing from the 4k to the 8k stone I use the collar to "supposedly" keep the angle the same using the 8k as it was using the 4k. HERE'S THE THING! The 8k stone removes such a tiny amount of steel per stroke I can look at the bevel after one stroke and see the different scratch pattern of the 8k and 4k stones. The 8k only touches the top of the bevel and leaves the edge apex alone. The coarser stones just removed enough steel to make it LOOK like the angle was the same because the new angle and scratch pattern is visible on the entire new bevel. The only way to get the 8k to hit the entire bevel at the same angle as the 4k stone did is to make a tiny, manual adjustment of the angle. This proves (to me) that when using higher grit stones a very slight error in angle can result in NOT hitting the apex on every stroke. This is even on the EP which is 10 times more accurate than when using the free hand method. Ok, for me this indicates the higher grit stones require more accuracy because they remove so much less steel than the coarser stones. I could be way off my angle goal using a 500 grit stone and I still can be hitting the apex because enough steel is being removed on each stroke to actually be establishing a new angle. But each angle will still be getting to the apex because of the amount of steel being removed. Using the 8k stone a tiny bit of steel is removed so to hit the top of a flat bevel and the bottom of the bevel (edge apex) on the same stroke the angle needs to be much more accurate. Even more accurate than .088 degrees. This is where my opinion is sitting right now. I am not convinced my opinion is 100% accurate or fool proof because I'm just recently getting to this level of sharpening in both ability and knowledge. Now when dealing with convex edges (which all free hand does) this theory of mine may fall apart BECAUSE we are no longer dealing with flat bevels. This is where your theory may end up holding more water than mine. I hope I explained my reasons for my opinion well enough to understand. My opinion is based on my using the EP and also my ability to get better results with higher grit stones as my ability improves. T his has also been evident when using strops. I have strop sprays down to .1 micron. The 8k Shapton glass stone is 1.84 micron. I bought sprays at .5 and .25 micron about 1.5 years ago I think. I already had some boron carbide semi-paste at 1 micron. I sove that stuff and recommend it highly. When I got the sprays I think I remember the .5 micron strop (leather) refining the edge after using the 1 micron but I'm not 100% sure. I am 100% sure that the strop I sprayed the .25 micron on was of absolutely NO USE TO ME. It just didn't seem to effect the edge at all. So, I decided I had blown my money and quit using that strop. Keep in mind that stropping at this micron level requires VERY light pressure. The weight of the blade or less. Several months later I tried the .25 strop and I was able to feel that the edge was more refined or smoother than after the .5 micron strop. My skill had improved. I can also now feel a difference after using the .1 micron strop. I do want to mention that I don't believe edges stropped on a strop under 1 micron will perform better than the 1 micron boron carbide strop. Not in real world application I mean. You'll never tell any difference in the edge on your pocket knife whan stropped on a 1 micron or .1 micron strop. Not when cutting cardboard or stuff like that. I can tell or feel the difference when slicing phone book pages or other very thin paper. So for real world use I've wasted my money on extremely fine grit sprays and the materials I have made strops with. Leather, glass, wood, balsa wood, etc. I have to be happy with the believe that I have and am still learning about sharpening knives. Gotta quit now. Seven fingers are tired and one is broken I think. lol I do want to add something. In the past rew months I've been emailing and talking on the phone with Ken Schwartz who is a well respected professional sharpener and the inventore of some of the best strop sprays on the market. In the past two weeks I've been communicating with another very experienced, professional sharpener. TONS of info in these two guy's minds. They know each other and have talked as well. I only wanted to mention that they differ in opinion about one pretty well known thought about free hand sharpening technique. One has one opinion and the other has another opinion on the same issue but both end up with supurb edges. Not only that, they can explain how they get those edges. Being able to explain the why's of a skill proves to me someone knows what they are doing and aren't just duplicating movements they learned. When two experts in any skill disagree but still get expert level results I just think that is interesting if not amazing.
Jack
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Permalink Reply by Stephen L. Corley on
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I just finished sharpening my Benchmade 551. It is the only knife I have that I kept a convex edge on. I used my Shaptons to sharpen it. In doing so I was constantly rocking the blade from an edge leading to an edge trailing stroke. I did not hit the apex every stroke but I hit it enough to sharpen the apex. It is not an exact technique, but it gives results the same as an exact technique. So, my assessment that lower grits require a person to be more exact I have proven to be false.
Now to EP's and other devises in that category. While they are effective and efficient, My son is here, I'll finish up tomorrow. -
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Let me clarify what I stared saying. Being exact isn't necessary. Your bevels don't have to be with a half a degree of each other, nor does every stroke need to be at the same angle. The majority of the time, when you are cutting something, you will not be holding your knife at a perfect 90 degrees. Therefore, your bevels don't need to be exact. As long as you finish the apex it doesn't matter if your bevel is completely flat. It's all very forgiving.
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Well Stephen, I just bought another stone and it's your fault. Bringing up sharpening discussions gives me the itch. :-) Actually, I've been looking at this 4k Shapton glass stone for a while. I had the 2k and 6k bench stones but sold them to fund other stones. I kept a full set of Shapton glass stones for the EP. At the time I had decided not to persue free hand sharpening. I got the 8k a while back. I wanted it for honing straight razors. Well, that's the justification I used. :-) So now I'll have the 4k also. So now I have all I need and will never buy another sharpening stone. Yeah right. :-)
Jack
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Jack, you should try convex sharpening.
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I have been working on those for a couple months or so. Just to test my angle accuracy on bench stones I have put flat bevels on knives with the EP then tried to keep the angle the same and also flat. THis has proven to be impossible. For 3-5 strokes I can feel the flat bevel when it sits on the stone. After a few strokes the flat bevel is becoming convex. So I decided to just increase my rocking of the blade as I stroke to intentionally create a convex edge. I just finished my son's Spyderco delica. I finished with the Shapton glass 8k and it has a very nice finish on it. Sharp too. :-) I took pictures of it and will try to post them tomorrow. It's nothing special as edges go but as I understand it when someone takes a picture and posts it others are required to look at it. :) I think it's a rule. :-) I want to send you a private message. I tried and I had to request you to be a friend. I can't send you the message until you accept. If you want to can you accept so I can send you some info you may like?
Jack
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I got you on the friend thing.
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Permalink Reply by Steve Hanner on
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Just catching up to this (have had my share of weather) But reading along and some great points you make. I intend to stay with stones and eventually a strop(Of some kind) Don't want to try a machine or invest in one. I think I would go broke buying them and then no money to buy knives!!
It sounds like with a lot of practice you are getting some great results and finding a few things along the way.
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I have been putting convex bevel/edges for a little while but since this thread I've paid more attention to what I was doing. I see exactly what you are talking about when you say every stroke doesn't have to be exactly the same or 100% accurate to end up with a great edge. In the past when using the EP I would normally put a back bevel (lower angle) and then finish the edge bevel at a higher angle. There was no need to reach the apex of the edge when doing the back bevel since I was sure to do that with the edge bevel. This meant two steps (back b evel and edge bevel). With the same idea in mind I tried to create a convex back bevel planning on finishing the edge when concentrating on the edge. What I found was that after I was done with the back bevel the edge was already VERY sharp. This was because since free hand can't ever be 100% accurate I was missing the target of stopping before the edge touched the stone and actually hitting the edge enough to sharpen it. This eliminated the second step of working on an edge bevel.. I did need to check for burrs and remove any I found but that only takes a minute or so. So paying more attention to a specific aspect of sharpening referenced by your post I too have changed my perspective. It still "makes sense" to me that the finer grit stones require more accuracy but wometimes what "makes sense" isn't always what happens in real life. W
hat is your opinion of the shapton glass stones now after using them? I ordered a 4k the other day and a 320 grit this morning. I've been putting off getting a coarser grit bench stone because I was planning on using the EP for re-profiling edges using coarser stones to set the angle and finishing with bench stones. But in the past few days I found myself wanting to at least be able to do the whole job free hand. So I ordered a 320 grit. After using it I will go to a DMT fine and extra-fine grit then the 4k and 8k SHapton glass. I have the 500 grit Shapton glass for the EP and it does great. The 320 I'm expecting to cut real fast. But the Shapton glass even though they cut fast don't leave a deep scratch pattern. Eager to hear what you think of the Shapton's (pros and cons).Jack
Stephen L. Corley said:Jack, you should try convex sharpening.
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Jack, with hind sight, I believe I should have gotten the Shaptons in 320, 1k, 3k, and 8k. As it is, I have a 2k and 4k to do the work I believe the 3k would have done. I would have saved money that way.
The 320 removes metal extremely fast and does not get loaded, nor does the 1k. The 2k will load but the 4k and 8k load real fast. I find that It is better to remove the swarf periodically. I do this by adding water to the stone and wiping it with my hand. So far, I haven't had an issue with metal splinters in my fingers. To add water, I have a 20oz. bottle with a hole punched in the cap. I start at one end of the stone and squirt to the other end. This washes most of the swarf off and then I wipe it with my hand. I follow this with a quick squirt to make sure I have plenty of water on it. On the 4k and 8k, sometimes I will use a fine grit diamond stone to work up a slurry. I think this helps prevent loading, but I'm not positive.
I believe the Shapton Glass Stones are the best investment I have made in knife care and maintenance. It was a long education process to get to the point where I could truly appreciate and implement them. All the years of trial and error was worth it.
I was going to make 2 videos today. 1 of convex sharpening the other of standard V bevel sharpening. I wasn't able to do it because my son went to play body guard for a few girls in New Orleans. I'm not sure, but I think they suckered him into going shopping. I'll get some made one day and post on here. -
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I believe I found you on facebook and have sent a friends request.
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Your hindsight may show you what you wish you had done but I know it will help others possibly make a better decision. I like learning from other people's mistakes so I think when we share what we did and then later share what may have been a better decision it helps others. When I started buying the Shaptons for the EP the 8k was out of stock and that was the one that came recommended as the first in the grit progression that would leave a mirror finish. I wanted the 8k but since I couldn't get it THAT DAY I ordered the 2k and 6k. A week or two later I had used the 6k and seeing it didn't leave a true mirror finish I got the 8k which was now in stock. I should have waited as I seldom use the 6k now. Although, having too many grits is better than not having enough. Big jumps in grits gets frustrating because you need to spend so much time on the finer stone. Going from my 500 grit to a 4 or 8k would mean hours (possibly) with the higher grit where the 1 or 2k thrown in the mix would save time. By the end of the month I should have the 320 and 4k stones to go with my 8k Shapton glass stones. Between the 320 and 4k I have DMT and Spyderco stones in enough grits to have a VERY easy progression. More stones than I need really. Some are not that expensive though and I bought them over time. I have thought about trying to use a diamond stone to create a slurry but haven't done it. I have some DMT 4" stones. Which grit do you recommend. I have XC through EF in that size. I just hate to waste stone by grinding it away with a slurry stone or even flattening them. Just a necessary evil I guess. :) Two really experienced sharpeners have both emphasized the importance of keeping the stones flat. I don't know that my skill is good enough for it to matter if I wait a little bit to flatten my stones. I'll go 4 or 5 knives or more sometimes before flattening them. Let me know what you think about the DMT grit to use as a slurry stone though. I think I'll try it. Why is it I don't think those girls had to twist your son's arm toooo hard? :)
Jack
Stephen L. Corley said:Jack, with hind sight, I believe I should have gotten the Shaptons in 320, 1k, 3k, and 8k. As it is, I have a 2k and 4k to do the work I believe the 3k would have done. I would have saved money that way.
The 320 removes metal extremely fast and does not get loaded, nor does the 1k. The 2k will load but the 4k and 8k load real fast. I find that It is better to remove the swarf periodically. I do this by adding water to the stone and wiping it with my hand. So far, I haven't had an issue with metal splinters in my fingers. To add water, I have a 20oz. bottle with a hole punched in the cap. I start at one end of the stone and squirt to the other end. This washes most of the swarf off and then I wipe it with my hand. I follow this with a quick squirt to make sure I have plenty of water on it. On the 4k and 8k, sometimes I will use a fine grit diamond stone to work up a slurry. I think this helps prevent loading, but I'm not positive.
I believe the Shapton Glass Stones are the best investment I have made in knife care and maintenance. It was a long education process to get to the point where I could truly appreciate and implement them. All the years of trial and error was worth it.
I was going to make 2 videos today. 1 of convex sharpening the other of standard V bevel sharpening. I wasn't able to do it because my son went to play body guard for a few girls in New Orleans. I'm not sure, but I think they suckered him into going shopping. I'll get some made one day and post on here. -
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