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Burr Free Sharpening Technique
#21
(10-03-2018, 12:10 PM)SteveG Wrote:
(10-03-2018, 11:02 AM)jasonstone20 Wrote:
(10-02-2018, 08:31 PM)SteveG Wrote:
(10-02-2018, 04:28 PM)jasonstone20 Wrote:
(10-02-2018, 01:27 PM)SteveG Wrote: The shaping step seems to be ok for me, so I get to the point where there's no visible light reflected from the edge, and I'm going to apply one or two high-angle passes to micro-bevel and form the apex.  First pass, still dull.  Next pass, still dull.  Keeps on going "still dull" until I can feel a burr - IOW, I'm either not going far enough, or too far, at which point I'm back to the strop just as I would have been if I did my more normal burr-based sharpening, but now that I have a microbevel the stropping is a little harder to get right.

Keep in mind that I don't have much experience at freehand sharpening, and it's likely my high-angle passes are too inconsistent to use this method well, so you'll probably have better results than I get.  Also note that I didn't/don't include back-bevelling (the step where, after adding the microbevel, you resharpen at the original angle to remove the microbevel) in the progression - I might be missing the point, but don't see that it adds any value and just gives me more opportunity to ruin the edge.

So, with all of that said, I can get to slicing phone book paper with the grain, and sometimes across the grain, with this method, but not push-cutting across the grain, which is kinda my threshold for sharp.

SteveG,
I had the same issue when first trying to use it.  I was able to communicate with Cliff and he walked me through the last part.  What I did after that was just take one knife and sharpened it for a week until I got the technique down.  In Cliff's video and forum post, he didn't explain that he had sharpened the knife in the video several times before so it looked a lot easier than it was.  

Here are the steps to the 3-Step Method:  

1. After the shaping stage, the knife should slice newsprint, and after apexing it should push cut.  With a knife that you are familiar with or if you can feel the feedback from the stone, this isn't that difficult as the edge feels a certain way on the stone right before it forms a burr.  I usually am not big on counting passes, but if I haven't sharpened a knife before or I can't feel the feedback on the stone for some reason, I will do sets of 5 or 10 passes per side until the edge slices newsprint (this is right after the shaping stage were the edge is no longer reflecting light).  

2. Then I will double the angle and set the apex, usually 5-10 alternating edge leading passes per side, then lower the angle to the original angle and do 1-5 passes alternating passes per side, checking  for sharpness.  

3. If the edge is not push cutting newsprint/phonebook paper by then, I check to see if there is a burr.  If no burr, I will do a few more edge leading alternating passes, again checking the sharpness.  If there is a burr, I repeat step 2, then check sharpness.

I have noticed that one of the issues that is causing problems, and the one I had, is going straight for no reflection of light to micro-beveling, and either not doing enough passes or overginding and forming a burr.  When I asked Cliff how to avoid overgrinding and forming a burr(that is the point of this technique, right?), he told me don't worry about forming a burr, just cut it off with the micro-bevel.  Another issue is that some try Plateau Sharpening first before they get the 3-Step method down, which is using one stone for shaping, doing alternating passes until the edge shaves while stopping before a burr is formed, and then apexing the edge with a micro-bevel.  This is a lot more tricky of a technique, as you need to double or triple the number of micro-bevel passes, and it doesn't give you the opportunity to do a lot of grit progressions, unlike the 3 Step Method, where you can insert as many stones as you like to get a mirror polish.
jasonstone,

  Thanks for the thoughtful and detailed explanation, I will incorporate that into my practice sessions.  I think your advice, as with most of the sound advice I hear, is to practice, and with practice will come success.  I've heard Cliff claim that anyone can learn this method in a very short time (don't remember for sure, but I think it was denominated in minutes); I've also read where someone mastered it in a year.  For you it was a week.  For me, it's not been dedicated practice, but I did buy a cheap paring knife to practice with, and once every week or so I'll give it a spin, so maybe in six months or a year I'll be wondering why it was so hard to figure out. 

  So, one question: are you applying the microbevel with the same stone you shaped with?  Actually, a second question: are you also back-bevelling with the same stone.  It sounds like you are; I've done it both with the same and with a finer stone (which is what I think you're referring to as Plateau Sharpening) - which points out one of my significant flaws in practicing (i.e., that I usually try something different each time I practice, which maybe means I shouldn't be calling it "practice").

  Thanks again for the tips, I'll be playing with those.

  Steve

SteveG,
I think Cliff was talking about people learning when taught in person.  Once you figure it out, it is really simple, just a little nuanced.  I don't always use the burr-free technique, but I have incorporated a few of it's techniques into my sharpening, and it is especially useful for when I am having difficulties.  I just find it doesn't take as much of my energy and concentration to just sharpen to a burr and remove it on the strop.  

As far as the micro-bevel, you want to apply it with the stone that has the desired apex finish.  Same with the back-beveling. For example, using DMT diamond hones, you shape on the C, refine the scratch pattern (just sharpening on the edge bevel, alternating edge leading passes),  with the F, and refine the scratch pattern with the EF, then micro-bevel and back-bevel with the EF.

Good point, there's nothing like a little one-on-one with someone who's mastered a skill.

Thanks for the additional details.  One other question: what angle(s) are you typically sharpening at?

As low as I can go, usually 10-15 degrees per side.
Reply
#22
(10-03-2018, 12:08 PM)SteveG Wrote:
(10-03-2018, 09:11 AM)Jan Wrote: I enjoy the fruitful discussion in this thread. Every post may be the missing stone in the mosaic how to proceed efficiently when deburring an edge. Smile
 
It's a temptation to find universal rule how to sharpen without a burr. In my understanding the burr formation process is not fully understood yet. It depends among others on physical properties of sharpened blade. The most important property is the ductility/brittleness of the blade. Ductile materials form large positive burrs while brittle materials form smaller negative burrs by break out mechanism.  
 
Nevertheless it is surely worth to look for a simple approach how to minimise the burr which is to some degree unavoidable phenomenon of sharpening.
 
Jan

I never thought of "negative burrs" as a way of expressing that concept - nice!  

Two other things worth noting (maybe, I'm not the most qualified observer here):

  - Most of the people I've heard of doing this method are using very acute sharpening angles, so even their high-angle passes are often lower than what I use regularly (20dps).
  - A point that's often emphasized is that the stone needs to cut. Sharp, fresh grit, otherwise you're just smearing/damaging the metal.  I've often wondered with edge-leading if that doesn't lead to the "negative burr" you referred to.  For me, as you alluded to, different steels respond dramatically to different stones.

Steve G, I have not invented the terms "positive and negative burrs", I saw it used in papers concerning machining.

Both, positive and negative burr can develop in an edge-trailing regime depending on ductility/brittleness of the sharpened blade. The attached picture schematically explains the burr formation process.

   

Jan


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#23
(10-03-2018, 09:52 PM)jasonstone20 Wrote:
(10-03-2018, 12:10 PM)SteveG Wrote:
(10-03-2018, 11:02 AM)jasonstone20 Wrote:
(10-02-2018, 08:31 PM)SteveG Wrote:
(10-02-2018, 04:28 PM)jasonstone20 Wrote: SteveG,
I had the same issue when first trying to use it.  I was able to communicate with Cliff and he walked me through the last part.  What I did after that was just take one knife and sharpened it for a week until I got the technique down.  In Cliff's video and forum post, he didn't explain that he had sharpened the knife in the video several times before so it looked a lot easier than it was.  

Here are the steps to the 3-Step Method:  

1. After the shaping stage, the knife should slice newsprint, and after apexing it should push cut.  With a knife that you are familiar with or if you can feel the feedback from the stone, this isn't that difficult as the edge feels a certain way on the stone right before it forms a burr.  I usually am not big on counting passes, but if I haven't sharpened a knife before or I can't feel the feedback on the stone for some reason, I will do sets of 5 or 10 passes per side until the edge slices newsprint (this is right after the shaping stage were the edge is no longer reflecting light).  

2. Then I will double the angle and set the apex, usually 5-10 alternating edge leading passes per side, then lower the angle to the original angle and do 1-5 passes alternating passes per side, checking  for sharpness.  

3. If the edge is not push cutting newsprint/phonebook paper by then, I check to see if there is a burr.  If no burr, I will do a few more edge leading alternating passes, again checking the sharpness.  If there is a burr, I repeat step 2, then check sharpness.

I have noticed that one of the issues that is causing problems, and the one I had, is going straight for no reflection of light to micro-beveling, and either not doing enough passes or overginding and forming a burr.  When I asked Cliff how to avoid overgrinding and forming a burr(that is the point of this technique, right?), he told me don't worry about forming a burr, just cut it off with the micro-bevel.  Another issue is that some try Plateau Sharpening first before they get the 3-Step method down, which is using one stone for shaping, doing alternating passes until the edge shaves while stopping before a burr is formed, and then apexing the edge with a micro-bevel.  This is a lot more tricky of a technique, as you need to double or triple the number of micro-bevel passes, and it doesn't give you the opportunity to do a lot of grit progressions, unlike the 3 Step Method, where you can insert as many stones as you like to get a mirror polish.
jasonstone,

  Thanks for the thoughtful and detailed explanation, I will incorporate that into my practice sessions.  I think your advice, as with most of the sound advice I hear, is to practice, and with practice will come success.  I've heard Cliff claim that anyone can learn this method in a very short time (don't remember for sure, but I think it was denominated in minutes); I've also read where someone mastered it in a year.  For you it was a week.  For me, it's not been dedicated practice, but I did buy a cheap paring knife to practice with, and once every week or so I'll give it a spin, so maybe in six months or a year I'll be wondering why it was so hard to figure out. 

  So, one question: are you applying the microbevel with the same stone you shaped with?  Actually, a second question: are you also back-bevelling with the same stone.  It sounds like you are; I've done it both with the same and with a finer stone (which is what I think you're referring to as Plateau Sharpening) - which points out one of my significant flaws in practicing (i.e., that I usually try something different each time I practice, which maybe means I shouldn't be calling it "practice").

  Thanks again for the tips, I'll be playing with those.

  Steve

SteveG,
I think Cliff was talking about people learning when taught in person.  Once you figure it out, it is really simple, just a little nuanced.  I don't always use the burr-free technique, but I have incorporated a few of it's techniques into my sharpening, and it is especially useful for when I am having difficulties.  I just find it doesn't take as much of my energy and concentration to just sharpen to a burr and remove it on the strop.  

As far as the micro-bevel, you want to apply it with the stone that has the desired apex finish.  Same with the back-beveling. For example, using DMT diamond hones, you shape on the C, refine the scratch pattern (just sharpening on the edge bevel, alternating edge leading passes),  with the F, and refine the scratch pattern with the EF, then micro-bevel and back-bevel with the EF.

Good point, there's nothing like a little one-on-one with someone who's mastered a skill.

Thanks for the additional details.  One other question: what angle(s) are you typically sharpening at?

As low as I can go, usually 10-15 degrees per side.
That's what I figured.  Between that and your comment that you can you can feel when the burr just starts to form, I can tell that you're a level or 2 or 3 above where I am, but I'll keep working on it.  Thanks again for all of the input.
Reply
#24
(10-04-2018, 02:12 AM)Jan Wrote:
(10-03-2018, 12:08 PM)SteveG Wrote:
(10-03-2018, 09:11 AM)Jan Wrote: I enjoy the fruitful discussion in this thread. Every post may be the missing stone in the mosaic how to proceed efficiently when deburring an edge. Smile
 
It's a temptation to find universal rule how to sharpen without a burr. In my understanding the burr formation process is not fully understood yet. It depends among others on physical properties of sharpened blade. The most important property is the ductility/brittleness of the blade. Ductile materials form large positive burrs while brittle materials form smaller negative burrs by break out mechanism.  
 
Nevertheless it is surely worth to look for a simple approach how to minimise the burr which is to some degree unavoidable phenomenon of sharpening.
 
Jan

I never thought of "negative burrs" as a way of expressing that concept - nice!  

Two other things worth noting (maybe, I'm not the most qualified observer here):

  - Most of the people I've heard of doing this method are using very acute sharpening angles, so even their high-angle passes are often lower than what I use regularly (20dps).
  - A point that's often emphasized is that the stone needs to cut. Sharp, fresh grit, otherwise you're just smearing/damaging the metal.  I've often wondered with edge-leading if that doesn't lead to the "negative burr" you referred to.  For me, as you alluded to, different steels respond dramatically to different stones.

Steve G, I have not invented the terms "positive and negative burrs", I saw it used in papers concerning machining.

Both, positive and negative burr can develop in an edge-trailing regime depending on ductility/brittleness of the sharpened blade. The attached picture schematically explains the burr formation process.



Jan

I've read some of the academic/research papers I could buy or get access to, but don't recall seeing this illustration before, and it's a very informative depiction.  Could you cite the reference (if it's not much trouble)?  I think it's from "Burrs - Analysis, Control and Removal: Proceedings of the CIRP International Conference on Burrs, 2nd-3rd April, 2009" (which is out of my price range - hoping there might be a stand-alone paper).  EDIT:  Shoot, I found the reference AFTER I posted this message - sorry for the misdirect.  For reference, I found it here: https://www.researchgate.net/publication...al_cutting
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#25
SteveG you are welcome. Smile

I have the picture form a paper: Aurich, J.C. & Dornfeld, David & Arrazola, Pedro & Franke, V & Leitz, L & Min, Sangkee. (2009). Burrs—Analysis, control and removal. Cirp Annals-manufacturing Technology - CIRP ANN-MANUF TECHNOL. 58. 519-542. 10.1016/j.cirp.2009.09.004.


Copy of the paper is here:
https://www.dropbox.com/s/xejqphzm94fpw8...l.pdf?dl=0

Jan


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#26
(10-05-2018, 10:14 PM)SteveG Wrote:
(10-03-2018, 09:52 PM)jasonstone20 Wrote:
(10-03-2018, 12:10 PM)SteveG Wrote:
(10-03-2018, 11:02 AM)jasonstone20 Wrote:
(10-02-2018, 08:31 PM)SteveG Wrote: jasonstone,

  Thanks for the thoughtful and detailed explanation, I will incorporate that into my practice sessions.  I think your advice, as with most of the sound advice I hear, is to practice, and with practice will come success.  I've heard Cliff claim that anyone can learn this method in a very short time (don't remember for sure, but I think it was denominated in minutes); I've also read where someone mastered it in a year.  For you it was a week.  For me, it's not been dedicated practice, but I did buy a cheap paring knife to practice with, and once every week or so I'll give it a spin, so maybe in six months or a year I'll be wondering why it was so hard to figure out. 

  So, one question: are you applying the microbevel with the same stone you shaped with?  Actually, a second question: are you also back-bevelling with the same stone.  It sounds like you are; I've done it both with the same and with a finer stone (which is what I think you're referring to as Plateau Sharpening) - which points out one of my significant flaws in practicing (i.e., that I usually try something different each time I practice, which maybe means I shouldn't be calling it "practice").

  Thanks again for the tips, I'll be playing with those.

  Steve

SteveG,
I think Cliff was talking about people learning when taught in person.  Once you figure it out, it is really simple, just a little nuanced.  I don't always use the burr-free technique, but I have incorporated a few of it's techniques into my sharpening, and it is especially useful for when I am having difficulties.  I just find it doesn't take as much of my energy and concentration to just sharpen to a burr and remove it on the strop.  

As far as the micro-bevel, you want to apply it with the stone that has the desired apex finish.  Same with the back-beveling. For example, using DMT diamond hones, you shape on the C, refine the scratch pattern (just sharpening on the edge bevel, alternating edge leading passes),  with the F, and refine the scratch pattern with the EF, then micro-bevel and back-bevel with the EF.

Good point, there's nothing like a little one-on-one with someone who's mastered a skill.

Thanks for the additional details.  One other question: what angle(s) are you typically sharpening at?

As low as I can go, usually 10-15 degrees per side.
That's what I figured.  Between that and your comment that you can you can feel when the burr just starts to form, I can tell that you're a level or 2 or 3 above where I am, but I'll keep working on it.  Thanks again for all of the input.

Thank you for the kind words.  Freehand sharpening is something that just takes doing it to understand what's going on, and when stuff starts to click and you get what people have been talking about is very rewarding.  Definitely worth the effort.  If you have any questions or issues that come up, please ask.  I have found that in life you can learn a lot more by passing on knowledge, rather than just a constant stream of input of information. Plus I enjoy talking about this type of stuff.   I think I have got the sharp part down somewhat, now I need to work on getting pretty edges along with sharp.  My email is jasonstone20@yahoo.com and I am pretty active on Cliff Stamps forum. 
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#27
[Image: Burr_formation.jpg]
The references given in this thread tell us that no sharpening can be burr-free, even when no burr can be detected.
The metal deformed at the edge by sharpening influences the properties of this edge weakening it.
Keeping in mind that cross-hatched in the illustration is the zone of plastic deformation, take a closer look at the negative burr final step, and note that even when no burr is hanging on the apex, we still have to hone away the deformed metal (cross-hatched) till the clean non-stressed edge.
http://knifeGrinders.com.au
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