Taking off the burr

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Cheddarnut
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Re: Taking off the burr

#21

Post by Cheddarnut »

Evil D wrote:
ABX2011 wrote:I try to keep burr formation to a minimum. As I apply the finishing strokes on a fine or ultra fine stone, I increase the angle and decrease the pressure to the lowest amount possible. I used to strop but no longer think it's necessary and it saves a step.

This.

Also people focus too much on higher grits and expect them to right the wrongs that you've done with the course stones. You need to make the knife as sharp as possible on EACH stone, not just the higher grit stuff. That means you need to not have a burr from the very first stone. Or, that's what works for me anyway.
so are we basically talking about an ultra minute micromicrobevel to finish?
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Re: Taking off the burr

#22

Post by Bill1170 »

The saw versus axe analogy for toothy versus polished edges is a very good one.

One thing that I wonder about is the edge of a katana. I was always under the impression that they are a polished edge. And yet, the katana is said to be wielded in a long arc, which is to say, in a slicing motion. It seems a toothy edge would perform better under those conditions of use. What am I missing?
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Re: Taking off the burr

#23

Post by Brunzenstein48 »

Bill1170 wrote:And yet, the katana is said to be wielded in a long arc, which is to say, in a slicing motion. It seems a toothy edge would perform better under those conditions of use. What am I missing?
Your missing nothing but your imho right on the mark!
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It is the one that is the most adaptable to change.”

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Re: Taking off the burr

#24

Post by Evil D »

Cheddarnut wrote:
Evil D wrote:
ABX2011 wrote:I try to keep burr formation to a minimum. As I apply the finishing strokes on a fine or ultra fine stone, I increase the angle and decrease the pressure to the lowest amount possible. I used to strop but no longer think it's necessary and it saves a step.

This.

Also people focus too much on higher grits and expect them to right the wrongs that you've done with the course stones. You need to make the knife as sharp as possible on EACH stone, not just the higher grit stuff. That means you need to not have a burr from the very first stone. Or, that's what works for me anyway.
so are we basically talking about an ultra minute micromicrobevel to finish?

Sort of, but it's almost the opposite of a micro bevel, since you end up hitting almost the entire bevel. I only increase the angle a couple degrees at best. It would make more sense to think of it as almost being a convex edge.
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Re: Taking off the burr

#25

Post by jackknifeh »

Here are some of my opinions at the moment. They may change over time as they have in the past. The primary goal of this post is to put an emphasis on PRACTICE.

An edge should be the meeting point (apex) of the bevels on opposite sides of a knife blade. It should be smooth on both sides until they meet.

A burr is unwanted steel on one side of the apex or the other. This steel needs to be removed. The result of removing a burr may depend on how big the burr is. The key to removing a burr is to ABRADE the burr until it is gone. The alternative to ABRADING a burr is to fold it out straight or to create a new burr on the other side.



Methods to remove a burr;
1. Using very light pressure glide the edge along the corner of a piece of soft wood or hard felt.
While a lot of expert knife sharpeners use and teach this method I am not a fan of it. First of all, I don’t like the fact that the last step in the sharpening process is to perform a motion like you were cutting into something. But mainly, it seems this method may snap a burr off instead of removing it by abrasion. If a burr snaps off the edge would be left uneven and the sharpness and cutting performance won’t be consistent.

2. Use a strop using trailing strokes.
I like this method as long as the amount of pressure is light enough to ABRADE the burr down to the apex without forming a burr on the other side of the edge apex. People can use any number of things to use as a strop. Some are very soft and some are harder. The key to this method is to use very light pressure. The reason is if you use too much pressure you could remove the burr but also create a new one on the other side. Use very light pressure so the burr (unwanted steel) is ABRADED down until you have a nice smooth edge apex.

3. Use a sharpening steel with trailing strokes.
I have never used these. I’ve heard several people mention the idea when using a steel is to “straighten the edge”. I think that means they want to fold out straight any steel that has rolled over during use or any burr that may be on the edge. If you actually do have a burr and fold it out straight the edge will be very sharp. But the folded steel will be very weak and may snap off very quickly during use. This will leave the edge (probably) not cutting as well as it should. Have you ever had a Coke can and bent the opening tab back and forth until it snaps off? The more you bend or fold the steel back and forth the weaker it gets until finally it snaps off. This is very similar to what happens when we “straighten the edge”. The edge apex needs to be comprised of good, hard steel that has never been bent of folded.


4. Just use EXTREMELY light strokes on the stones you are using to sharpen the knife. Push strokes or trailing strokes is simply a matter of preference IMO.
This is the method I prefer over the others. I’m not saying the other methods don’t work. That is dependent on how skilled each of us is in the method we choose to use. Over the past few years I’ve learned and tried the different methods and I have been pretty successful at all of them except using a sharpening steel. During these few years I’ve been reading lots of opinions on forums, watching videos, etc. Over time I got a picture in my head of a burr on the edge and also a perfectly formed edge apex. When I picture a burr on the edge I can envision folding it out straight or even possibly FOLDING it over to the other side. I don’t know if “folding it to the other side” really happens or if the new burr is new steel after the original burr was removed. We all have probably seen the drawing of a knife edge which shows a view as looking at the tip of a knife and seeing both sides of the edge. This shows a nice clean edge. The micro-bevel along with another bevel above it and then the rest of the blade. Here is the only picture I do have to show.

Image



A burr would be unwanted steel on either side of this pictured knife edge. IMO, the perfect way to get rid of a burr is to ABRADE the burr down with the same stone I have been using until the edge bevel (or micro-bevel) is smooth and even from the top of the bevel to the edge apex. BUT, don’t abrade any more than this. More abrasion can create a new burr on the other side. Then you have THAT burr to deal with. You can see how it looks like a burr can be flopped back and forth. But if removing a burr properly on the side of the edge where it is you won’t need to remove another burr from the other side.

I think that’s enough about the “intellect” of removing a burr. We’ve all heard, read and watched how this is accomplished. A burr is unwanted steel that needs to be removed. It’s very simple and not hard to grasp.

However, the difficult part is accomplished in the minutes, hours, days, weeks, months and years a person puts forth the effort to accomplish this. Depending on how sharp you want to get a knife will determine how much practice you need. If you want to be able to get a knife sharp enough to shave your arm hair and have a bald spot after 2 or 3 passes, that may not take too much time. 30 minutes per day for 30 days (for example). Even before that you will be getting your knives sharp enough to open mail, boxes, do some whittling, etc. But, if you want really sharp, hair whittling, face shaving edges be ready to not get those edges for a year or so. Maybe two years. Maybe three. I compare learning how to get edges this sharp to learning to play guitar. In a little while you can play guitar well enough for friends to know what song you are “trying”  to play. But NO ONE would ever pay to hear you play. :( But if you keep practicing (with focus) you will get better and better. Same thing when learning to remove burrs and sharpening a knife as a whole.

My point is we need to understand what a burr is and we need to have a plan on removing it with a particular method and/or tool. The intellectual understanding comes fast, almost immediately if it’s explained well. However, the “understanding” you have after lots and lots of time and practice will then become an “understanding” and ability you have that can’t be explained to other people. It’s more of a “feeling” you develop when learning to do something. Another thing is as you learn to sharpen, make sure you buy good quality tools (stones and/or strops). Then when you have tools that have been recommended by lots of people who are very good at sharpening don’t go buying any more. Wait a few months. When you are successful with those tools it’s a good time to try other types of stones or strops or whatever. But, once you have developed the skill to use the first set of stones you may decide you don’t need anything else. Buying another stone will not improve your ability. It never did mine anyway. Now I have three different set “type” stones and they all work.

There are lots of books, videos and forum posts about light pressure, too much pressure, low angle, high angle, stones, strops, ect. etc. etc. That’s all good but also we need to spend a lot of time practicing. If you want to keep getting better even after your knives are pretty sharp you need to keep practicing. Sharpen your knife as sharp as you can get it. Then try to cut your stone in half (in an area not used for sharpening). The goal here is to dull the knife so you can practice sharpening it again. Then do it again. Again. Again. I don’t work anymore and there isn’t much to hinder me having the time to practice learning to get my knives sharper and sharper. In the past 5 years I have on many days put in 2 hours per day. I’ve literally spent 6 hours in a single day on a few occasions just sitting there sharpening and dulling the same knife over and over. Also, trying to put lower and higher angles on the edge. It didn’t take long for me to learn you need a few really cheap knives for this amount of practicing so you don’t sharpen your nice knives until the blade is much smaller. Another thing about this practice time. Use the higher grit stones. This way you will need to perform LOTS more strokes than you would normally use. Performing LOTS more strokes in this “practicing” situation is all you want anyway. Lots and lots of strokes without removing much steel. Keep the angle as consistent as you can and just keep repeating the process. If you opt to get a sharpening system (EP, WE, Lansky, etc.) you will have more control of the edge angle and you will probably be getting edges super sharp much faster. Still, like any tool it takes a while to master the use of these sharpening systems. Whatever success you get at first will be better after you learn the little tricks that help the performance of any different tool.

I’ve spent some time writing this and if you are still here you spent some time reading it. I hope it has been of help BUT, I bet you didn’t read anything you haven’t already read at least once. The journey to being able to get knives to the level of sharpness that is above average is a fairly long one. It takes a lot of time practicing. This is not a problem though. If you really want to be able to get knives super scary sharp the practice time won’t be a burden. It will be part of the joy. If it is a burden don’t worry about it. Spend that time doing something that brings joy to your life. We already have enough burdens. :)

When you can feel the abrasion occurring you will see how it can't be explained effectively for someone else to do it without also putting in a bunch of practice time. After enough practice and improvement I finally understand what I have been reading all along. And I'm still learning as time goes on.

Jack
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Re: Taking off the burr

#26

Post by Donut »

Cliff Stamp wrote:
paladin wrote:Cliff, does a polished edge, that is properly apexed, maintain sharpness longer / better vs. a more roughly finished edge?
At a basic level it is like using an axe and a saw. If you try to chop with a saw you will not think it cuts wood very well and you will quickly beat the teeth apart. If you try to saw with an axe you would wonder why anyone would ever argue it cuts wood well. Now of course that is silly really, but that is the same thing as comparing low vs high grit edges. They excel at different types of cutting and they are pretty horrible when used where the other excels.
I think that explanation is not silly at all. That's an excellent example that explains it very well, at a simple level.
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Re: Taking off the burr

#27

Post by Cliff Stamp »

Bill1170 wrote: One thing that I wonder about is the edge of a katana. I was always under the impression that they are a polished edge. And yet, the katana is said to be wielded in a long arc, which is to say, in a slicing motion.
Bill, I think the best way to think about this is to realize that what is being talked about here isn't really a draw cut as in an extended slice like a saw, but is a cut more of like a skew chisel or guillotine. If you look at the face of a wood chopping axe for example it has a light arc, it isn't a straight line. There are a number of reasons for this, but a smooth cut and increase penetration is one of them.

However there is a lot of myth about katanas and much of the cutting that is done with them claiming some kind of extreme performance has been demonstrated with straight swords. In fact some of the cutting has even been done with fully blunt swords showing that bamboo and even tatami cutting doesn't often show what it claims it is showing.
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Re: Taking off the burr

#28

Post by Cliff Stamp »

jackknifeh wrote: However, the difficult part is accomplished in the minutes, hours, days, weeks, months and years a person puts forth the effort to accomplish this. Depending on how sharp you want to get a knife will determine how much practice you need. If you want to be able to get a knife sharp enough to shave your arm hair and have a bald spot after 2 or 3 passes, that may not take too much time. 30 minutes per day for 30 days (for example). Even before that you will be getting your knives sharp enough to open mail, boxes, do some whittling, etc. But, if you want really sharp, hair whittling, face shaving edges be ready to not get those edges for a year or so. Maybe two years. Maybe three.
I think this is really over stating the effort/skill required to sharpen. The biggest issue I find is people combining all of the steps into often what is one muddled goal. If you ask someone how to change a tire for example you get a very simple set of steps :

-break the lugs
-jack up the car
-remove the wheel
-change the tire
-put on the lugs
-remove the jack
-set the lugs

Each one of these steps is really simple and they are not confused. For example no one would take the jack and try to use it to remove the lugs or use the wrench to try to pry up the car. But with sharpening people often don't separate it and end up doing exactly that. Murray Carter was the first person I really see take the view of sharpening similar to how people change a tire into breaking into very separate steps.

I show people how to sharpen with a very simple process, just two steps :

-grind the edge to form an apex
-form an apex bevel

These are two very different steps and if you understand what you are doing in both then most of the confusion about sharpening goes away. A Spyderco Medium stone for example is very nice for setting an an apex, not so for the edge grind. A Naniwa Superstone 400 is the exact opposite. Sharpening can be very frustrating or very easy just by swapping the stones and using the exact same technique otherwise.
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Re: Taking off the burr

#29

Post by jackknifeh »

Cliff Stamp wrote:
jackknifeh wrote: However, the difficult part is accomplished in the minutes, hours, days, weeks, months and years a person puts forth the effort to accomplish this. Depending on how sharp you want to get a knife will determine how much practice you need. If you want to be able to get a knife sharp enough to shave your arm hair and have a bald spot after 2 or 3 passes, that may not take too much time. 30 minutes per day for 30 days (for example). Even before that you will be getting your knives sharp enough to open mail, boxes, do some whittling, etc. But, if you want really sharp, hair whittling, face shaving edges be ready to not get those edges for a year or so. Maybe two years. Maybe three.
I think this is really over stating the effort/skill required to sharpen. The biggest issue I find is people combining all of the steps into often what is one muddled goal. If you ask someone how to change a tire for example you get a very simple set of steps :

-break the lugs
-jack up the car
-remove the wheel
-change the tire
-put on the lugs
-remove the jack
-set the lugs

Each one of these steps is really simple and they are not confused. For example no one would take the jack and try to use it to remove the lugs or use the wrench to try to pry up the car. But with sharpening people often don't separate it and end up doing exactly that. Murray Carter was the first person I really see take the view of sharpening similar to how people change a tire into breaking into very separate steps.

I show people how to sharpen with a very simple process, just two steps :

-grind the edge to form an apex
-form an apex bevel

These are two very different steps and if you understand what you are doing in both then most of the confusion about sharpening goes away. A Spyderco Medium stone for example is very nice for setting an an apex, not so for the edge grind. A Naniwa Superstone 400 is the exact opposite. Sharpening can be very frustrating or very easy just by swapping the stones and using the exact same technique otherwise.
I agree about this 100%. Breaking the process down for understanding purposes is always good IMO. But the one thing I think is missed and what I was wanting to emphasize in discussing learning to sharpen a knife (or any skill for that matter) is the "feeling" or "touch" that is developed over time. This can't be communicated in the written word any more than I just did by typing the words feeling or touch. Another way to explain what I'm thinking on this subject is trying to tell someone how much "bottom english" to put on the cue ball to draw it back 16" with a 3" margin of error on where the cue ball stops. And I mean being able to do this consistently 7 out of 10 times. You just can't explain how it feels to do that so someone else can do it. He/she needs to take the steps required and do it over and over. At some point he/she will start developing the knowledge of where the cue tip needs to strike the cue ball and how hard to hit it and all that stuff. I used to play pool a lot and excercises like that were a big part of learning to play. When learning to sharpen I have on a few occasions gotten a knife MUCH sharper than I ever did before. Then I have mistakenly thought "WOW, I'm really a good knife sharpener now". Then I couldn't repeat this because the reason I got the knife that sharp was a lucky stroke on the very last stroke on the stone. I luckily had the exact angle and pressure needed for the extra sharpness I got but couldn't repeat consistently. It was just like making a shot playing pool that is unbelievable. Yes, I made the shot but I couldn't do it again if I had a million tries. So I kept practicing learning to sharpen. I wasn't really practicing getting a knife sharp. I was practicing maintaining a consistent angle throughout the stroke. I'd paint the edge with a marker and see how consistently I could repeat the strokes hitting the same spot along the edge as close as I could. Musicians practice repeatedly running scales, chord progressions, etc. Pool players practice different excercises for object ball accuracy, cue ball control, throw, into-the-rail shots, etc. I believe sharpening a knife, while much less skill demanding than a musical instrument or playing pool at the higher levels still requires a determined practice routine. I am speaking of myself and NO ONE ELSE. I had a friend in junior high thru high school who could play every song Ted Nugent recorded easily when he was in the 10th grade. He could play guitar as easily as I could walk. I have never been "good" at anything without a lot of work. No prodigy in these shoes. :) I emphasize this to encourage people learning to sharpen to keep at it. The ability to get hair whittling edges doesn't happen over night no matter how well you understand the process and what is really happening to the edge even at a microscopic level. It's different for every one I know and I think I'm as slow as anyone in areas like this. I'm not claiming I'm the best knife sharpener either. But, I've come a long long way in the past 5 years. And 5 years ago I was already sharpening knives to the point they could shave my arm hair in 2-3 passes.

Anyone who has gotten real good at a skill requiring hand/eye coordination knows what I'm referring to when it comes to a skill. There's a point where you pass the basic level and advance to a level that can't be taught, only learned.

I probably have beaten this dead horse enough. :)

Jack

PS
One reason it may have taken so long for me to improve is I was always trying a different stone, a different sharpening system, etc. Someone would praise the Shapton glass stones so I'd buy a couple and maybe in the back of my mind I was thinking that would speed up the time frame until I was getting knives super sharp. What really would have shortened the time frame I believe would have been to choose a method and tools and just worked with them. Keep it simple. This echoes Murray Carter's theory that sharpening a knife is 99% ability and 1% the tools. So while taking my word for something is questionable I think Mr. Carter's opinion deserve's more respect.
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Re: Taking off the burr

#30

Post by Bill1170 »

Cliff Stamp wrote:
Bill1170 wrote: One thing that I wonder about is the edge of a katana. I was always under the impression that they are a polished edge. And yet, the katana is said to be wielded in a long arc, which is to say, in a slicing motion.
Bill, I think the best way to think about this is to realize that what is being talked about here isn't really a draw cut as in an extended slice like a saw, but is a cut more of like a skew chisel or guillotine. If you look at the face of a wood chopping axe for example it has a light arc, it isn't a straight line. There are a number of reasons for this, but a smooth cut and increase penetration is one of them.

However there is a lot of myth about katanas and much of the cutting that is done with them claiming some kind of extreme performance has been demonstrated with straight swords. In fact some of the cutting has even been done with fully blunt swords showing that bamboo and even tatami cutting doesn't often show what it claims it is showing.
Thanks, Cliff. I get what you're saying. The thing about shearing cuts is that they fall on a continuum. The skew chisel and the axe swung in an arc have both a shearing and a push-cutting aspect to the cut. But a santoku drawn across a tomato has much more shearing component than the felling axe swung true.

What surprises me is how little shear angle it can take to make a big difference in cut quality/ease. Helical rotary cutters inclined only 10 degrees from normal (to feed direction) make an enormously smoother and quieter rip cut in solid wood than straight knives do. It feels counterintuitive that such a modest shear angle makes such a big difference. However, these are high speed cutters, and cutting speed seems to play a big role in cutting dynamics. I think speed has a lot to do with why cuts made with whizzing swords behave differently than what we typically experience with shorter (and therefore slower moving) knives in our kitchens.
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Re: Taking off the burr

#31

Post by Cliff Stamp »

Bill,

Cutting mechanics is oddly rarely discussed but in many cases it is far more critical to cutting than steel or even blade geometry. Speed is very critical when cutting a target which is free to move, not so much when the target is fixed and in rigid position. In most cases the differences can be understood by thinking about the basic mechanics of both the blade and the object being cut.

If you take a blade and try to slowly cut a small flexible piece of wood like an alder, or even worse scrub brush, then even if the blade is ground so it cuts very well, it will almost certainly just push the blade out of the way. This is simply because the wood can move as fast as the blade so the two essentially just move as one object in collision.

But if the blade is moving very fast then the wood can't move out of the way as it actually takes time for it to accelerate from rest as the blade is exerting forces on it. By the time it has come up to speed as the blade then the blade has already passed through it.

Skew cuts can also be looked at in the same way, one of the large changes is that they reduce the compression forces which build up right in front of the blade as they allow material to move away from the edge vs being push backwards into the other material which in effect makes the material harder.
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Re: Taking off the burr

#32

Post by Donut »

Cliff, I wanted to mention that sharpmaker thing, but don't feel like reviving that thread.

I prefer using 30 degree angles. I went to touch up the edge on my Caly 3 CF/ZDP this morning. I did 15 passes per side with the medium flats and tested it on paper; it tore the paper. I swapped the stones, left for right and right for left, did 15 more passes and tested it on paper; it cut the paper.

I feel like 40 degree would have less of a difference, when I used to not hit the edge I would use the 40 degree slots.
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Re: Taking off the burr

#33

Post by Cliff Stamp »

Donut,

Ever since I made that video I have suggested this to people who have issues with the Sharpmaker. In some cases it solved the problem immediately. It is such a trivial thing to check and solve in any case.

Always nice to hear anything being used for the better.
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Re: Taking off the burr

#34

Post by Donut »

I will probably go and measure the angle of all my rods and mark them for consistency, but until then, I can just swap them when they aren't working.
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Re: Taking off the burr

#35

Post by Cliff Stamp »

jackknifeh wrote:
But the one thing I think is missed and what I was wanting to emphasize in discussing learning to sharpen a knife (or any skill for that matter) is the "feeling" or "touch" that is developed over time.
Jack, that is one of the largest differences between us, I don't sharpen by that kind of subjective/feel type approach and it isn't part of how I teach people. It is just a purely mechanical activity like changing a tire. I see the process as very simple, and I introduce it currently by two steps and I focus on the actual physical changes to the knife :

a) form an apex on a knife which already has the edge properly set for the apex

This is the opposite for how most people learn to sharpen, however I can make a strong argument as to why it makes much more sense to start there. This takes almost no skill, all you are doing is setting a micro-bevel on a knife which is ready to take one. Most people when they react to seeing this work think it is almost cheating it is so simple. However the next step is just as simple as long as you don't try to muddle it into the first one.

b) grind the edge until it is properly set to the apex

Now because you already know how to do (a), once you know how to do (b) the job is done. I don't concentrate on how the knife feels or sounds. I just show them how it is done on a large scale wooden mockup and sandpaper so they can physically see and understand what is happening. These two steps are really easy to do individually.

However different approaches for different people, my background is in measurement, hence my viewpoint is completely quantitative. Lots of people view sharpening more like an art, if it works for you then do it that way.
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Re: Taking off the burr

#36

Post by JD Spydo »

Brunzenstein48 wrote:I use a leftover cork from a wine bottle - works perfect.
That's really interesting because I've heard of people in Europe using cork wood to strop with in the past. Not all strops are created equal by any means. Not even all leather passes the test either. I got a strop from a company that sells straight razors and it is made from Russian Boar hide. I've never found any USA made leather strops to work as well as it does.

I also have a strop that I got from Garrett Wade about 10 years ago>> it is on a wooden paddle that has hollow sections in it so when you strop your blade it has a lot of give in it>> it works well IMO.

Deburring is like a science among master machinists. There is a master machinist named Laroux Gillespie who has written an entire book on Deburring>> I would like to have that book but it costs over $150 :eek: Also I've found that the ULtra-Fine stone in the 204 Sharpmaker seems to deburr nicely.
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Re: Taking off the burr

#37

Post by Brunzenstein48 »

JD Spydo wrote:
Brunzenstein48 wrote:I use a leftover cork from a wine bottle - works perfect.
That's really interesting because I've heard of people in Europe using cork wood to strop with in the past.
Comparing stroping the very same blade with a DMT paste with wine cork and comparing the result side by side to Spyderco sharpmaker's ultra fine rods produce under the microscope (150x) clearly visible & different marks on the blade but no distinguishable difference in the reals world e.g. when cutting tomatoes, paring fish or cutting phone book paper /cardboard - so the discussion what may be better is imho purely academic.
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It is the one that is the most adaptable to change.”

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Re: Taking off the burr

#38

Post by jackknifeh »

Cliff Stamp wrote:
jackknifeh wrote:
But the one thing I think is missed and what I was wanting to emphasize in discussing learning to sharpen a knife (or any skill for that matter) is the "feeling" or "touch" that is developed over time.
Jack, that is one of the largest differences between us, I don't sharpen by that kind of subjective/feel type approach and it isn't part of how I teach people. It is just a purely mechanical activity like changing a tire. I see the process as very simple, and I introduce it currently by two steps and I focus on the actual physical changes to the knife :

a) form an apex on a knife which already has the edge properly set for the apex

This is the opposite for how most people learn to sharpen, however I can make a strong argument as to why it makes much more sense to start there. This takes almost no skill, all you are doing is setting a micro-bevel on a knife which is ready to take one. Most people when they react to seeing this work think it is almost cheating it is so simple. However the next step is just as simple as long as you don't try to muddle it into the first one.

b) grind the edge until it is properly set to the apex

Now because you already know how to do (a), once you know how to do (b) the job is done. I don't concentrate on how the knife feels or sounds. I just show them how it is done on a large scale wooden mockup and sandpaper so they can physically see and understand what is happening. These two steps are really easy to do individually.

However different approaches for different people, my background is in measurement, hence my viewpoint is completely quantitative. Lots of people view sharpening more like an art, if it works for you then do it that way.
By wooden mockup do you mean you whittle a wooden knife for someone to learn with using sandpaper as the stone? If so, that sounds like one of those ingenious things once you hear about it you wonder why it never occurred to you before. Learning the steps and quickly seeing them happen on a wooden knife is a great idea I think.

Let me ask about your two steps to make sure I understand what you said. It sounds like in step a) you put the edge apex on the edge and then in step b) you lower the angle to create a back bevel to thin the blade or edge right above the apex. Is this what you meant? If so, couldn't you do the steps in reverse? Create the lower angle bevel first then raise the spine to create the edge bevel or apex? Which bevel to form first seems to be one of the things some people do one way and others do it the other way. Maybe they develop the step order because they were taught that way. I've considered this question as I've been learning and now it doesn't seem to matter which you do first in the long run. Maybe creating the edge apex first would be better in case you are interrupted. At least then the knife is cutting even if not at it's peak performance. No matter. When teaching anything it's best to keep things simple. Don't even suggest there's another way until the student is comfortable with a known method that works. Then address other techniques or order of steps to get them prepared for situations where they may opt to leave the learned routine and become more versatile. Anyway, your two steps and a wooden knife sound like a perfect knife sharpening 101 class. :)

About the "feel" or "touch" I feel when sharpening a knife. This can't be explained and it can't be taught. I feel a bit goofy even talking about it in regards to sharpening a knife. Sharpening a knife is a pretty simple thing. Sometimes we make it more complicated than it really is. Anyway, think of "in the zone". It's more often referred to with other activities. The people who understand are the ones who know how it "feels" to reach for the football when the quarterback threw it 6" too far and it "feels" like your arm stretches that extra little bit to grab it with 1 cm of one finger of one hand and bring it down just as you cross the goal line. Or the musician or basketball player who are obviously "in the zone". Or when the pitcher becomes "one" with the ball and the catcher's mit. Or when Chevy Chase becomes the ball. :) Being in the zone when doing anything I believe comes after all the steps have been mastered and something else happens. It can happen with strictly mental activities also. The mathematician who is so into the problem becomes aware of the solution. He took all the formulas he has learned over the years and then put them together in a way that solves the problem he is working on and then we have a brand new, inexpensive fuel source for all of mankind. Being "in the zone" can apply to any activity I guess. And again, it can't be explained nor taught. Maybe that's one of the greater things about it.

I've seen your videos Cliff about sharpening and when you slice paper it's easy to tell the knife is very, very sharp. It seems obvious that the edges you create are as sharp as some of the best knife sharpeners around create. The only way to determine if your knife is sharper than Murray Carter's (example) knife would be to test the sharpness in a laboratory setting. As far as just using the knife I'm betting yours are as sharp as needed for any every day task. Even the more demanding tasks. Now to get the edges this sharp I believe you get "into the zone". I may be wrong but even if you don't get into the zone when sharpening I'm betting you get there when doing your testing and compiling the results into charts and graphs that illustrate your findings. I believe you do a great job of sharpening and you do a great job of illustrating your findings on whatever you decide to test. I am only me and I can only base my thinking on how I've felt over my 56 years but I find it hard to believe you get the results you do without being "in the zone". Even if being "in the zone" when doing the things you do mean following the steps perfectly, every time to get consistent results. If you weren't "in the zone" you may skip a step or make a mistake that ruins the whole day's work. The same way the basketball player who is in the zone looses his focus for a split second while shooting and misses the shot. Maybe being "in focus" is a better phrase than "in the zone". I also believe when being "in the zone" happens that's when people take all the knowledge and experience, put them together and discover something new. Something no one else has thought of. Like using a wooden knife (or popsickle stick) and sandpaper to learn to sharpen a knife. :)

Something else about getting in the zone is even after all the basics are set in stone in your mind you need to do an insane amount of practicing the activity. Learning how to use only a tiny bit of pressure with the knife edge on a stone is one thing. Learning you can balance the knife on your fingers to change the amount of pressure on the stone is one thing. But, being able to do it is something else entirely. Knowing you can let the knife rest on your middle finger placed at different locations on the handle will change the amount of pressure (weight) on the stone isn't enough. You need to do it many times before you can use this knowledge effectively. Now to get back on subject of the thread. I think it requires a very tiny amount of pressure on the stone to remove the super small burr while not creating a burr on the other side of the edge. In addition to "knowing" this we need to practice enough to be able to do it and do it well. I don't understand how anyone could do this without being able to "feel" the contact and friction and pressure of the edge on the stone. Of course some people need more or less practice than other people. Some people learn faster than others obviously. Over time I've gotten pretty good at some things and also watched other people become pretty good (or very good) at things and it's obvious to me that I'm not a fast learner. I've seen fast learners and it has amazed me how quickly they grasp an idea and master the activity. Especially children. But when initially learning anything it's essential to "follow the steps" and not even think about zones. Learn the basics, practice a lot and the "zone" or the "focus" will come automatically. Or it won't. Probably depends on how much you really care about the activity you are learning.

That's enough about in the zone. :)

Jack
Cliff Stamp
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Re: Taking off the burr

#39

Post by Cliff Stamp »

JD Spydo wrote:.... I would like to have that book but it costs over $150
Here is an on-line reference on the same subject :

- http://www.diva-portal.org/smash/get/di ... TEXT01.pdf" onclick="window.open(this.href);return false;

It is an engineering masters thesis on deburring.

Note that in engineering, deburring is a fairly wide phenomena which basically just means in forming processes shapes are not perfectly formed and that any termination point will have some kind of plastic deformation. If you were to take a piece of aluminum for example and drive a nail through it then you see the aluminum driven out around the nail. That is a particular type of burr though it isn't generally how it is thought of in the knife industry which is just one small facet of burrs in engineering.
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Re: Taking off the burr

#40

Post by Ecchi-Spud »

ON A SIDE NOTE:

This regards guided sharpeners, like the Sharpmaker, where you have the stones/sticks set at preset angles on a base and you gently run the knife edge across the sticks going downward. The issue that I have is that the preset angles typically aren't the ones needed to work the edge at the preferred angle(s), like for jackknifeh's image below (and sometimes not even at the angles they're labeled at -- a simple protractor can reveal that)
jackknifeh wrote:
Image
Now I recently purchased a crock-stick setup for sharpening the few blades I have (Sorry, everyone - and especially Sal - it's not a Sharpmaker; like I've mentioned before, I've only recently started on knives as an interest/hobby), and future blades (may have to get a better set-up for harder steels; hopefully by then, I'll be more practiced). And it occurred to me that there MIGHT be a way to REDUCE the actual angles one sharpens at, by simply ROTATING the sharpener off-perpendicular. That way, when you gently run the edge across the sticks (along the triangle edge for the Sharpmaker sticks; not the flat), you're at the desired angle(s) needed. With a little bit of basic trigonometry, I even determined a formula for how much the sharpener would have to be rotated to reach the desired angle:
cos R = (sin D) / (sin A)

R = Angle off of perpendicular that the sharpener would have to be rotated (between 0 and 90 degrees)
D = Desired angle (per side) for sharpening (D less than A)
A = Actual angle of the stick in the sharpener (again, per side)

There's a long story on how to arrive at this formula.
The idea being that, with the addition of a simple protractor (maybe the same one you use to determine the ACTUAL angle of the sharpening sticks), a sheet of paper with a line drawn on it, and a good scientific calculator, one could practically DIAL IN the desired sharpening angle to work on the knife edge. Problem is, some of the angles needed to rotate the sharpener can be high (for example, to take a 20-degree angle down to 15 degrees, the sharpener would have to be rotated about 41 degrees off-perpendicular). Also, since the sticks are now no longer perpendicular to yourself, the length of the actual knife strokes would be different (possibly shorter for the stick now angled away from you, longer for the one angled closer). And there may be other problems that I'm not seeing ATM (if you think of something I'm missing here, PLEASE LET ME KNOW!!!).

Any thoughts? Something I miss? Do I need to take remedial trigonometry or consult a psychiatrist? (NOTE: I haven't done this to any of my blades YET; like I keep stating, I'm still new to all of this.)
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