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Thread: What is sharpening a knife about? (2015 updates!)

  1. #101
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    Thanks, just funny to read some of my mistakes there.
    I felt like "is there a camera here? How does he know what I do?".

    For example, I was SURE that "blurr = you did it wrong" so I was moving (with the SAME stone or pole) from one side to the other FOREVER, because like you explain the blurr just moves. You can only make it smaller with a finer stone or grit.

    Ok. I still have questions.
    But I am not sure is this the place, so I make a thread.

    Thanks again.
    Last edited by Sir Joe; 08-30-2015 at 06:45 PM.

  2. #102

    New sections for 2015!

    NEW SECTIONS FOR 2015!


    How long will my sharp edge last?

    That depends on how often you use the knife, what you use it for, the steel and heat treatment, and also edge geometry. Generally, cheap Ikea knives will dull fast because they are made of soft metals with poor wear-resistance. And there’s a reason why people joke that they have never seen a Swiss Army Knife with a sharp blade: Victorinox/Wenger run their steels pretty soft, and the steel is idealized for corrosion-resistance, not edge retention (has a ton of Chromium, I think 13% or 15% or so). Good CPM D2 and modern “super steels” hold an edge much longer. And of course, cutting cardboard or other tough work will dull an edge quickly. But cutting cardboard will dull a Swiss Army Knife faster than a Dozier D2 knife or high-end Elmax knife. A thin edge angle on a knife made of super steel run very hard will last very long.


    A note on stropping

    Stropping is very beneficial for your edge. However, a common misperception is that stropping is about burr removal. You need to do your burr removal on the stones (although with very aggressive compound like bark river black compound, especially on something like the HeavyHanded washboard, you can strop to remove burrs). I don’t recommend that for new sharpeners because you should be honing (no pun intended) your stone skills to the point where you can remove burrs on a stone. Stropping does get rid of the tiniest burrs, as well as smoothing the edge out (refining), which people have found gives them a better-performing edge.

    After a good sharpening at any grit, give it a few good passes with decent pressure, at a slightly higher angle, on newspaper or jeans (or an old leather belt), both with and against the grain of your sharpening job, and you will immediately see a difference, so it’s worth doing. How does that work? Because newsprint, cardboard, leather, and your jeans contain silicates, which are harder than steel. Using good green compound or diamond sprays on cased leather, balsa wood, paper, etc. will allow you to strop faster, with better results and less pressure. High-quality, cased horsehide leather, without compound, is excellent as a final, finishing step for highly refined edges on quality steels.


    Tips on sharpening your old, used, dull kitchen or pocket knife

    These can be the most frustrating knives for a new sharpener. Frankly, these knives are a challenge even for experienced sharpeners because they have factory edges (which weren’t very good to begin with -- uneven bevels, coarse grinds that were then polished sharp with a buffing wheel coated with white compound, etc.). This is where I highly recommend a loupe (I now reach for a 22X loupe when I feel like using one), as you will see what I am talking about. With a powerful loupe, you will see the thick grind lines of the factory edge, and you will see how those grind lines seem smooth and “melted” where the wheel and compound buffed them sharp. And you will see the dings, nicks, and chips on the apex that were not evident to your naked eye, that came from months or years of chopping, cutting, etc. To truly sharpen such a knife (and to do a good job), you need to basically grind past all that damage (factory edge, chips, dings, and all), until you have established your scratch pattern and created a smooth, even bevel with no more traces of those dings, chips, nicks, and factory grinds at the apex. That takes time. It means removing a good amount of metal. So choose a good, coarse stone (200-600grit) and work it, work it, work it until you’ve established your bevel. As I mentioned when I first wrote this three years ago, 90% of your work is with that first stone. After that, you’re gravy. Just move up in grit (it will go quickly) until you’ve got the refinement you want.


    What equipment we reach for

    Funny thing, I saw a vid a few years ago of CrimsonTideShooter, who -- after years of making hair-whittling, mirror-polished edges on all of his knives -- had come to the conclusion that a DMT coarse stone followed by stropping with 1 micron spray on leather gave him an excellent, all-around edge that was suitable for most cutting work with most knives. I have found the same over time. I think everyone who is serious about sharpening will eventually get the “bug” and will gravitate toward trying to get hair-whittling edges and mirrored bevels, but then eventually will back off and realizes that that’s pointless for 95% of purposes. Do it if you must to get it out of your system and prove to yourself that you can (in fact, I would encourage you to do it for the experience). In my kitchen right now, I have a pair of cheap 420HC kitchen knives, and I use a standard 6” DMT fine benchstone and strop on newsprint exclusively to sharpen them. Gets the job done and makes a darn good edge.


    I want to start now! How do I practice?

    First of all, practice on your own knives. You probably own a Buck 110, a Swiss Army knife, a few Ikea or Henckels kitchen knives, etc. Those are good candidates. You can also sharpen other people’s knives for free (I did this, and that is when my sharpening took off. I put an ad in the company newsletter and got dozens of requests. I ended up sharpening hundreds of knives that way). Do your high-end knives when you are comfortable with the process. That will give you a sense of just how wear-resistant modern steels are (S30V, Elmax, etc.). Frankly, though, although they take more time to sharpen, those super steels are, imho, “easier” to sharpen because their extreme wear resistance and hardness are very forgiving of bad angles. Honestly, some of the most difficult knives to sharpen are the cheap, flexible carving knives that everyone seems to own. Those are very, very good practice because you really have to get the angle nailed down, and you have to use good pressure control to make sure you are contacting the stone correctly at the edge.


    Common question: Is the Spyderco Sharpmaker a good system, and can I sharpen a dull edge (i.e., reprofile) with it?

    Answer: Yes! But I strongly recommend you get the diamond rods. Check out the vid below to watch my technique for reprofiling a dull, damaged factory edge with the Sharpmaker. It can indeed be done and done quickly. With the diamond rods, the Sharpmaker will do everything you need a set of stones to do. They are expensive but worth every penny. A note on the ceramic rods that come with the set: the stones are very hard ceramics and need to be cleaned every few uses. Use a scouring pad. They are also quite fragile, so don’t drop them or treat them roughly. Lots of people have chipped or broken their Sharpmaker rods by accidentally dropping them. Spyderco has good customer service (in my experience) and will replace a rod if it is chipped from the store (and they sometimes are, especially the brown “medium” rods).




    Reprofiling a dull, damaged edge with the Sharpmaker

    Last edited by Magnaminous_G; 09-01-2015 at 10:35 PM.

  3. #103
    Quote Originally Posted by Sir Joe View Post
    Thanks, just funny to read some of my mistakes there.
    I felt like "is there a camera here? How does he know what I do?".

    For example, I was SURE that "blurr = you did it wrong" so I was moving (with the SAME stone or pole) from one side to the other FOREVER, because like you explain the blurr just moves. You can only make it smaller with a finer stone or grit.

    Ok. I still have questions.
    But I am not sure is this the place, so I make a thread.

    Thanks again.


    You are very welcome! To answer your question, you can reduce the burr just fine with the same stone. You just use lighter pressure and fewer strokes until you are just “kissing” the stone, until you are alternating feather-light, one-to-one strokes per side. You can even do this with a diamond stone. Like all things sharpening-related, it just takes practice. See my Sharpmaker vid in the above post!

  4. #104
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    Hmmm, so, cardboard is not good.
    Another thing learned from you.
    But why?
    So maybe are my little cheap knives not so bad. I thought they were bad because they were loosing the edge just after opening a sack of Cement.
    Well, that is not really cardboard but just two layers of a bit thick paper. And a knife should not lose its edge after opening a couple of those things.
    But still. What's wrong with cardboard?
    Why should a knife should be able to cut roots but not cardboard?

    Thanks for the new infos.

  5. #105
    Quote Originally Posted by Sir Joe View Post
    Hmmm, so, cardboard is not good.
    Another thing learned from you.
    But why?
    So maybe are my little cheap knives not so bad. I thought they were bad because they were loosing the edge just after opening a sack of Cement.
    Well, that is not really cardboard but just two layers of a bit thick paper. And a knife should not lose its edge after opening a couple of those things.
    But still. What's wrong with cardboard?
    Why should a knife should be able to cut roots but not cardboard?

    Thanks for the new infos.

    Carboard, drywall, cement sacks... all very tough on an edge, and especially tough on a "cheap knife," as you say. That said, lots of people cut cardboard all day long for a living. They will all attest to it being very punishing on their edges, although I have seen pics and vids of people cutting quite a large amount of cardboard and still having a good working edge on their knife. Granted, they are usually demonstrating the performance of a high-end knife made of modern super steel with a very good edge put on. I can totally see a knife edge dulling from opening a sack of cement (although I've never done that). It may just be two layers of paper, but keep in mind with all that cement stuff on it (plus being very heavy and coarse unrefined brown paper), it wouldn't surprise me to see a cheap knife dull a fair bit after opening just a few cement bags.

    So yes, I think you are right, and I think what you are seeing is totally normal. A cheap knife would not stand up to cutting a lot of cardboard, and probably would not stand up to opening a lot of cement bags. They are just tough on a knife edge because they contain tons of silicates and minerals that are punishing on an edge.

  6. #106
    Alright, so I'm new to sharpening and I have a knife I've basically marked for death a designated sharpening knife. It's a 3.625" blade and I've tried freehand sharpening with my 6" DMT stones (325, 600, 1200) and the edge looks refined but cannot cut paper or nearly anything. A few questions I have include how to properly remove a burr. I've been running the blade through a piece of wood and a whole ton of metal comes off. What should the hand motion be while sharpening a blade with a curve (like drop/clip point) or when the blade is longer than the stone? I know it's bad to move the wrist so what should I do? Do I just pull the knife directly towards me so the tip contacts the stone? Or do I raise my elbow/arm? I'm really lost on some things and would appreciate any guidance. My attempts so far have been pretty bad.
    Last edited by Taigei; 09-05-2015 at 02:58 PM.

  7. #107
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    Quote Originally Posted by Magnaminous_G View Post
    A cheap knife would not stand up to cutting a lot of cardboard
    Depends on what you consider a lot. 3000+ ft and still slicing paper on a $6 knife.

    Taigei, how are you sharpening with the DMT's? Stone on table, stone in other hand, stone in vice, high pressure, low pressure, edge leading, edge trailing, etc? How far off the stone is the spine of the blade? How wide and how thick is the blade? I have not found drawing through wood to be much help in removing a large burr. The best way I've found to remove a burr is to double the angle of the edge and take 1 or 2 very light passes, less than the weight of the knife, with edge leading strokes. If it is a knife that has been used hard, or a knife made from soft steel then it might add one or 2 more steps to the process.

  8. #108
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    Great video, thanks

  9. Would anyone have recommendations on the sharpmaker versus the new worksharp guided?

  10. #110
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    Quote Originally Posted by firefighterguy View Post
    Would anyone have recommendations on the sharpmaker versus the new worksharp guided?
    Yep,

    Buy stones, they will take you further and allow you to sharpen a broader range of tools. Stay away from power tools so you don't mess up knives (you will mess up knives) and you should be ok.

    I would recommend a 1000 grit waterstone such as the Shapton pro. Once you become proficient with this stone you can add others from the line-up to better assist you in sharpening. The key is sticking with one thing long enough to get good at it, it's all about developing the skill and no matter what tools you use it always comes back to the skill level of the sharpener. The Work sharp or a $1000 Wicked edge package will not teach you to sharpen.

  11. #111
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    Hi Mag,

    I had lost your thread
    Found again thanks to recommendation of Chris on my Thread about the difference between CBN and Diamond rods by Spyderco.
    You (and anybody else who knows about that) are invited to answer there. So that if people in the future make a forum search for title, they can find it better.

    I wanted now to ask you about reprofiling etc. I am going to buy some folders. Good steel, S110V, M390, and than maybe also a VG10 and a CMP154.
    The aim is slice. No stabbing or other things. So I want to have a very thin edge. But probably some of those knives will come with 40 or more °.
    Now, on the Sharpmaker Video, the Spyderco man says that Spyderco makes their knives with 30° so that people can sharpen them at 40 (which is more stable and resistant) with good results for longer time.
    If I follow this same principle, but my final aim is a 30° instead of a 40°, should I reprofile at 20° for than making a microbevel at 30°? Or should I directly make 30° like I suppose you are doing on your video here above?

    And for this reprofile is it better the sharpmaker or a metal file?

  12. #112
    Quote Originally Posted by Sir Joe View Post
    Hi Mag,

    I had lost your thread
    Found again thanks to recommendation of Chris on my Thread about the difference between CBN and Diamond rods by Spyderco.
    You (and anybody else who knows about that) are invited to answer there. So that if people in the future make a forum search for title, they can find it better.

    I wanted now to ask you about reprofiling etc. I am going to buy some folders. Good steel, S110V, M390, and than maybe also a VG10 and a CMP154.
    The aim is slice. No stabbing or other things. So I want to have a very thin edge. But probably some of those knives will come with 40 or more °.
    Now, on the Sharpmaker Video, the Spyderco man says that Spyderco makes their knives with 30° so that people can sharpen them at 40 (which is more stable and resistant) with good results for longer time.
    If I follow this same principle, but my final aim is a 30° instead of a 40°, should I reprofile at 20° for than making a microbevel at 30°? Or should I directly make 30° like I suppose you are doing on your video here above?

    And for this reprofile is it better the sharpmaker or a metal file?

    Regarding the Sharpmaker rods, I have the CBN rods on order. Never used them before. I like the Sharpmaker diamond rods, and I'll try out the CBN rods out when I get them.

    As for your reprofiling question, you can't reprofile to 20° on the Sharpmaker unless you jury rig it up somehow. The choices are 30° or 40°. But I think your idea is a good one. Personally, I daily carry a knife with a 20° primary bevel, and I touch it up with a 30° Sharpmaker microbevel, which sounds like exactly what you are trying to do. It's a good choice, in my opinion. I reprofiled the primary bevel by hand to 20°, but I can freehand almost any angle degree (I know because I double check with a goniometer).

    If you can't freehand a 20° angle, then you'll have to go with a guided system, or send it to someone to do it for you, or find a way to jury rig the Sharpmaker.

    But if you just want to go straight 30° bevel, that is fine, too. Depending on the steel and knife geometry (especially if you have a modern tactical folder with a thick blade of modern super steel run very hard), you could be grinding for a long time, even using the Sharpmaker technique in the vid above. In which case, you might just want to send it to someone for a regrind... so in that case, you might just want to ask them to do 20° so you can maintain the 30° secondary bevel with your Sharpmaker. Lots of options.

    As for reprofiling with a metal file, sounds like a lot of messy and inaccurate work, but maybe some people do, I dunno.

  13. #113
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    For me sharpening a knife is a zen like way to relax

    I think that most people will agree with 95% of what you said, not that I disagree with any of it. The 5% is for the personal methods that work for the individual, which we all have.

    I go WAY over on grit size. That is, personally I go up to 4000 or 8000 (for some knives) and then 1 micron diamond paste. The reason is that my knife sharpening has been influenced by sharpening chisels, and I have the stones. Chisels are taken to a much finer edge than most knives would ever be taken. I take my EDC's much higher than 2000, but I agree with you. As you pointed out, somewhere above 1000 and below 2000 is a nice balance (for a kitchen knife at least). Though, for knives exclusively used on meat I have found that going higher isn't a waste of time. Tomato skin being mostly cellulose, is actually really tough, (newspaper strop?). To extend your example, cheap micro-serrated knives are great on tomatoes but absolute garbage with meat.

    Any benefits of going above and beyond 2000 grit are COMPLETELY subjective. But, in my experience my EDC's tend to hold their edge much better by going above 4000. I've spent a morning hacking away at wood, and still had an arm shaving edge when I was done. I doubt it's my technique so I can only surmise that going higher does make a slight difference in terms of longevity.

    I will disagree to an extent with using the strop to remove the burr. When sharpening, I finish with some leather impregnated with diapaste. I may be doing it "wrong", but this shortcut seems to work quite well. I'm not saying that we shouldn't be taught to use the stone on the burr, but if you can strop AND remove the burr in one step why not? Maybe I'm just putting more steps between the first stone and strop than I need to, as per your reference to CrimsonTide's massive jump.

    Great post, now on to angles?

  14. #114
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    Quote Originally Posted by Magnaminous_G View Post
    Regarding the Sharpmaker rods, I have the CBN rods on order. Never used them before. I like the Sharpmaker diamond rods, and I'll try out the CBN rods out when I get them.
    As for your reprofiling question, you can't reprofile to 20° on the Sharpmaker unless you jury rig it up somehow.
    Let us know how they compare! I may still change my mind. After all I must wait 2 weeks to have a good discount
    The 20°, right, no, I surely cannot free hand so good as you, but I was thinking, also the 30 and 40 on the sharpmaker is not soooooooooo precise. It is not sooo easy to go straight down with the knife and keeping it perfectly perpendicular to the table.
    I thought that there is a slight margin of tolerance. Is there none?
    For the 20° I was thinking about just giving the knife a slight inclination.
    I prefer doing it myself, also the reprofiling, but eventually I could ask the shop to do it for me, you are right, at least the first time.
    I want anyway to experiment with a diamond 120 (like dmt extra extra coarse, although I plan to buy a lansky foldable 120/600) right on the sides of the bevel before passing to the cbn rods.

    Do you have any records of which companies use polycristalline diamond on their sharpeners, and which use mono?

    Quote Originally Posted by nine4t4 View Post
    For me sharpening a knife is a zen like way to relax
    funny, I just wrote the same somewhere else

  15. #115
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    Quote Originally Posted by Magnaminous_G View Post
    As for your reprofiling question, you can't reprofile to 20° on the Sharpmaker unless you jury rig it up somehow.
    If you rest the Sharpmaker base on one of the rods, with the rod at the exact centre, you can rock it from side to side to give a lower angle. Rock it so that the rod you're using is up. That gives about a 4 degree change if you're using the base with the lid attached to form a handle, making the bevel angle 22 degrees.

  16. #116
    New member, first post.

    For me sharpening is a decease. I can't get my knives sharp enough. Up until reasently I used a Lansky sharpening system and got fairly sharp knives. A week ago I bought a Tormek T4 + a kit of various jigs. I'm still learning but I've gotten at least a few newspapercutting knives now. Will buy the 4000 grit japanese stone soon to get my knives sharper. I told you it's a desease.

    https://youtu.be/j2qwRERusSw
    https://youtu.be/i9XmdmOurWA

  17. #117
    Quote Originally Posted by nine4t4 View Post
    For me sharpening a knife is a zen like way to relax

    I think that most people will agree with 95% of what you said, not that I disagree with any of it. The 5% is for the personal methods that work for the individual, which we all have.

    I go WAY over on grit size. That is, personally I go up to 4000 or 8000 (for some knives) and then 1 micron diamond paste. The reason is that my knife sharpening has been influenced by sharpening chisels, and I have the stones. Chisels are taken to a much finer edge than most knives would ever be taken. I take my EDC's much higher than 2000, but I agree with you. As you pointed out, somewhere above 1000 and below 2000 is a nice balance (for a kitchen knife at least). Though, for knives exclusively used on meat I have found that going higher isn't a waste of time. Tomato skin being mostly cellulose, is actually really tough, (newspaper strop?). To extend your example, cheap micro-serrated knives are great on tomatoes but absolute garbage with meat.

    Any benefits of going above and beyond 2000 grit are COMPLETELY subjective. But, in my experience my EDC's tend to hold their edge much better by going above 4000. I've spent a morning hacking away at wood, and still had an arm shaving edge when I was done. I doubt it's my technique so I can only surmise that going higher does make a slight difference in terms of longevity.
    I agree that for chopping wood, a highly-polished edge is best.


    I will disagree to an extent with using the strop to remove the burr. When sharpening, I finish with some leather impregnated with diapaste. I may be doing it "wrong", but this shortcut seems to work quite well. I'm not saying that we shouldn't be taught to use the stone on the burr, but if you can strop AND remove the burr in one step why not? Maybe I'm just putting more steps between the first stone and strop than I need to, as per your reference to CrimsonTide's massive jump.
    Sure, if you already know you can deburr on a stone, why not? But if you can't, then that's a valuable skill to develop, and you absolutely should be able to do it first.


    Great post, now on to angles?
    What about angles?

  18. #118
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    Very insightful. Wish I would have had this a few years ago

  19. #119
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    Apex the edge, refine it. Funny how it took me years of struggling and reading before I actually realized it really is this simple.

  20. #120
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    I gotta say getting a 30x glass loupe was the best thing i ever bought for sharpening, and it was only like $5 online. and when i use a guided rod lansky type system and it still very helpfull. there are times i think im ready to move on to the next stone and before i do i always inspect the edge from heel to tip and fairly often i see something that i missed by feel. without the loupe i would have gone to the next finer stone before i should have. Its a great tool that everyone should have, i use mine all the time and not just for sharpening.
    Last edited by rogerxd45; 10-23-2015 at 11:15 PM.

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