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Thread: Hesitate to ask a sharpening question

  1. #31
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    I sharpen knives for high-end chefs and use Chosera and sometimes Shapton and usually I go to 5k or 10k depending on the quality of the knife they give me. (I'm the only local person that can properly sharpen a single-bevel Japanese knife, and for those I may go as far as 15k because they are usually very special knives with picky owners.) Just mentioning this to say that when I gifted my father-in-law a set of waterstones to start with, I gave him a set of Nortons. They are a great deal for the money, and I knew he would never get beyond that basic set. Their 8k is extremely soft, but it leaves a nice finish. You are fine stopping with that.

    I personally do see some difference when I go to 15k, but it's a very minor difference, and to be honest, I usually only do that on smoothers that I am using on difficult woods, or chisels for paring. - add to that- sometimes just because I like to play around with sharpening stuff as sharp as I can, so I may sharpen something more than it really needs just because I'm a sick individual who LIKES to sharpen stuff! :-)

    If you send me an iron, I will sharpen it to 15k for you, and you can see how much difference it makes for you. PM me for my address. I'll even pay postage on my end- you pay postage to send to me. Why would I do this? Because I believe we should use our talents and pass them on, and I like helping others with sharpening questions. Knowledge not shared is lost!

  2. #32
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    Theoretically if the 'ruler trick' micro bevel is so small it is removed by sharpening the main bevel each time you could claim it works.
    As the angle is so small the bevel gets long very quickly on a stone. It might work with a flat leather strop where the blade is flat to the leather and the pressure curves the leather very slightly at the blade edge as you pull backwards.

    The most obvious shortcoming is caused by a stone not being totally flat. When you sharpen the main bevel the edge created will gain some variation from the stone's imperfections. Adding a second bevel will only increase those variations at the edge. It also forms a burr on the main bevel. Pushing the burr ('the wire') back and forth is less than satisfactory, you are left trying to balance it in the middle. It will of course wiggle from side to side due to the stones imperfections. Dealing with one bevel intersecting a plane surface has to give a straighter edge.

    This ultimate flat surface is hard to obtain, in the case of a 'poor' flat surface the false 'flat' surface of a secondary bevel may indeed be better hence giving a seemingly better edge, imperfections included.

    So it seems to me that very good traditional technique should be capable of giving the better edge, but the ruler shortcut may work better for some.

    The ruler shortcut commits a blade to that method, recovery is a lot of work. In a school workshop sticking to the traditional method makes sense.

    I agree that working on your technique first is crucial. Sharpen, walk away then later be very critical. This is how I sharpen a knife. Start again from scratch. After 8 years my main camp knife now has a great convex edge I can no longer improve. The D2 steel was not the limiting factor, I was.

  3. #33
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    Quote Originally Posted by David Sloan View Post
    I had a lot of fun over the holiday break tuning up my older and newer planes. I did a lot of sharpening and that skill has significantly improved. There is definitely room for improvement. This forum has helped me as well as books/youtube etc. I use Norton stones progressing through 8K. My question is this. The higher grit stones are very expensive and I understand you can really polish the blades but do the experienced sharpeners feel that going to 12K,15K, 30 K produces a measurable improvement in edge performance. Thanks and as a newcomer to the Creek, I really enjoy this and the other Creek forums.
    Yes, absolutely, all things being equal, higher grits can yield higher degrees of sharpness. If you have mastered 8K, then kick it up a notch to 12k.

  4. #34
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    Quote Originally Posted by bridger berdel View Post
    Not me. I've discovered that there is someone on the internet who is wrong, and I'll not rest until they have been set aright.
    https://xkcd.com/386/

  5. #35
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    Quote Originally Posted by david charlesworth View Post
    The back of a plane blade is not messed up by the ruler trick.
    I am always stunned and bemused when folks inveigh against the ruler trick and then turn around and suggest *stropping* the blade back.

    The reason is of course that both involve exactly the same tradeoff: They both sacrifice flatness (whether due to the compliance of the strop material or by intentionally "tipping" the blade with a shim) in order to achieve better polish at the leading edge. They both work, and they can both cause problems if taken too far.

    The wood doesn't care whether you do it the "traditional way" or the "new way".
    Last edited by Patrick Chase; 01-20-2017 at 7:49 PM.

  6. #36
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    Quote Originally Posted by David Sloan View Post
    I had a lot of fun over the holiday break tuning up my older and newer planes. I did a lot of sharpening and that skill has significantly improved. There is definitely room for improvement. This forum has helped me as well as books/youtube etc. I use Norton stones progressing through 8K. My question is this. The higher grit stones are very expensive and I understand you can really polish the blades but do the experienced sharpeners feel that going to 12K,15K, 30 K produces a measurable improvement in edge performance. Thanks and as a newcomer to the Creek, I really enjoy this and the other Creek forums.
    I mostly fall into the "diminishing returns" camp, with one important caveat: There are multiple systems and specifications governing grit number (6K, 10K, etc), so any one individual's experience of where diminishing returns start may not be relevant to anybody else.

    The usual way around that issue is to speak in terms of abrasive particle size (measured in microns) instead of grit. Here are some examples to demonstrate why grit is problematic, using "8000 grit" stones:


    • Jim Koepke's #8000 Norton water stone uses 3 um abrasive particles
    • Naniwa's #8000 "Snow White" stone uses 2 um particles IIRC
    • Shapton's #8000 Pro stone uses 1.74 um particles
    • Imanishi and Sigma Power #8000 stones use ~1.2 um particles. This is also what the latest JIS spec for rating grit calls out.


    As you can see there's a 2.5:1 range of particle sizes represented in just this small selection of identically-rated stones.

    I personally think "diminishing returns" start somewhere above 1.2 um, which is #8000 in the Sigma and Imanishi systems. I personally won't pay more than $90 (the price for the Sigma #13000, which has 0.74 um abrasive particles) for a synthetic waterstone.

    Interestingly enough, the manufacturers who charge hundreds of dollars for their top-of-the-line polishing stones happen to be two of the biggest scofflaws for "grit-rating inflation"...
    Last edited by Patrick Chase; 01-20-2017 at 7:52 PM.

  7. #37
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    Quote Originally Posted by Patrick Chase View Post
    I am always stunned and bemused when folks inveigh against the ruler trick and then turn around and suggest *stropping* the blade back.

    The reason is of course that both involve exactly the same tradeoff: They both sacrifice flatness (whether due to the compliance of the strop material or by intentionally "tipping" the blade with a shim) in order to achieve better polish at the leading edge. They both work, and they can both cause problems if taken too far.

    The wood doesn't care whether you do it the "traditional way" or the "new way".
    Thanks for posting that because I've been scratching my head over exactly that thought.

    Is 4-5 swipes with the ruler method on a 10-12K stone that much different from a dozen strops with green compound?

    I'm totally new to this level of sharpening, and only now getting decent results but it does seem like stropping the back on compound at an angle much higher that the ruler method, would alter the geometry of the back much the same as the ruler method itself.

  8. #38
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    I've got it!

    The obvious answer is ruler stropping!

  9. #39
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    Jim Koepke's #8000 Norton water stone uses 3 um abrasive particles
    This is interesting and agrees with the specifications in the (current) Norton 2015 catalog:

    http://www.nortonabrasives.com/sites...ed.pdf#page=52

    What is strange is a chart from 2007 puts the Norton 8000 water stone at 1.2µ particle size.

    The question is was the 2007 chart in error or has Norton changed their stone? (error more likely?)

    There is lust in my heart for a finer stone, just because. There are also moths in my wallet when it comes to spending that kind of money for an increase in sharpness that would be hard to justify since my edges can perform quite well with my current sharpening equipment. Maybe if an urge to get my straight razor in shaving shape came over me, one of these would be advantageous. How can that be explained to SWMBO in such a way as she will be the one to suggest it is worth the money?

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  10. #40
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    Quote Originally Posted by Patrick Chase View Post
    I am always stunned and bemused when folks inveigh against the ruler trick and then turn around and suggest *stropping* the blade back.

    The reason is of course that both involve exactly the same tradeoff: They both sacrifice flatness (whether due to the compliance of the strop material or by intentionally "tipping" the blade with a shim) in order to achieve better polish at the leading edge. They both work, and they can both cause problems if taken too far.

    The wood doesn't care whether you do it the "traditional way" or the "new way".
    Patrick; you may wish to refer to the comments within my post. (a non user of Ruler Trick.)

    regards Stewie;

    What needs to be understood is that the principal behind working to those higher grits of honing stone, is to wear away that fine line of metal that holds the burr in place. By stopping too soon on those higher grits of honing stone, there is increased likelihood you will tear the burr off prematurely, as you move onto the leather strop. Premature removal of the burr will likely result in microscopic damage to the blades cutting edge.

    Work on the strop should be brief, with little more that 1 or 2 passes on each side of the blade. Over strop, then you risk rounding over the cutting edge due to the inherent give within the leather surface.

    Maintaining a flat surface on your stones should never be underrated if your primary goal is to improve your sharpening technique. imo.

    Stewie;

  11. #41
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    Quote Originally Posted by Jim Koepke View Post
    This is interesting and agrees with the specifications in the (current) Norton 2015 catalog:

    http://www.nortonabrasives.com/sites...ed.pdf#page=52

    What is strange is a chart from 2007 puts the Norton 8000 water stone at 1.2µ particle size.

    The question is was the 2007 chart in error or has Norton changed their stone? (error more likely?)

    There is lust in my heart for a finer stone, just because. There are also moths in my wallet when it comes to spending that kind of money for an increase in sharpness that would be hard to justify since my edges can perform quite well with my current sharpening equipment. Maybe if an urge to get my straight razor in shaving shape came over me, one of these would be advantageous. How can that be explained to SWMBO in such a way as she will be the one to suggest it is worth the money?

    jtk
    Tell her that if money gets tight you can always sell it and get 50 cents on the dollar

  12. #42
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    Quote Originally Posted by Jim Koepke View Post
    There is lust in my heart for a finer stone, just because. There are also moths in my wallet when it comes to spending that kind of money for an increase in sharpness that would be hard to justify since my edges can perform quite well with my current sharpening equipment. Maybe if an urge to get my straight razor in shaving shape came over me, one of these would be advantageous. How can that be explained to SWMBO in such a way as she will be the one to suggest it is worth the money?

    jtk
    Do you sharpen her kitchen knives? It may be difficult to convince her to sign off on a $500 stone, but $150 might be seen as a reward to a good and faithful servant, especially if the money was used to make her job easier.

    And then there is the sneaky approach. Save pennies away from her eagle eye. Buy the stone in time. Lose the receipt. Lose the new box. Treat it like you have owned it for years. Unless she is sharper than most non-woodworkers, she will not notice. Kinda like leaving the house to go to the gun range with an empty gun case, and returning home with it not so empty.

    Stan

  13. #43
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    Quote Originally Posted by Stewie Simpson View Post
    Patrick; you may wish to refer to the comments within my post. (a non user of Ruler Trick.)

    regards Stewie;
    Fair enough.

    I'd argue that that's conceptually very similar to what I do with the ruler trick: I use a thin shim to limit the angle to ~1/4 deg, and I limit the "tricked" portion of the blade to a couple/few tenths of a millimeter. The edge is therefore only recessed from the back by about a micron (0.3*tan(1/4)).

    And that brings me back to my point: Both stropping and ruler-tricking involve tradeoffs between geometric deformation and polishing, and they can both be done in either minimalist ways that cause very little geometry change (as you do with stropping and I do with ruler-tricking) or more "enthusiastically".
    Last edited by Patrick Chase; 01-20-2017 at 11:45 PM.

  14. #44
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    Quote Originally Posted by Patrick Chase View Post
    I personally think "diminishing returns" start somewhere above 1.2 um, which is #8000 in the Sigma and Imanishi systems. I personally won't pay more than $90 (the price for the Sigma #13000, which has 0.74 um abrasive particles) for a synthetic waterstone.
    Upon re-reading this I realized that it wasn't terribly clear in the above-quoted remark: I think that by 1.2 um we are already into diminishing returns for real-world uses where the objective is the finish quality of the wood (as opposed to, say, the thinnest possible shavings). I can detect differences in the edge itself and in hanging hair/thread tests from honing on finer abrasives, but it doesn't seem to translate to better finished surfaces in most situations.

    I should also note that some abrasives are more "aggressive" than others, and that may shift the point of diminishing returns. I usually stop at ~1 um with AlOx/Alumina-ceramic waterstones, but I typically go to 0.5 um with diamond paste or lapping film because diamonds tends to leave sharper striations.

  15. #45
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    Upon re-reading this I realized that it wasn't terribly clear in the above-quoted remark: I think that by 1.2 um we are already into diminishing returns for real-world uses where the objective is the finish quality of the wood (as opposed to, say, the thinnest possible shavings). I can detect differences in the edge itself and in hanging hair/thread tests from honing on finer abrasives, but it doesn't seem to translate to better finished surfaces in most situations.

    I should also note that some abrasives are more "aggressive" than others, and that may shift the point of diminishing returns. I usually stop at ~1 um with AlOx/Alumina-ceramic waterstones, but I typically go to 0.5 um with diamond paste or lapping film because diamonds tends to leave sharper striations.
    For the mother god , what's happened to the simple approach within woodworking.
    Last edited by Stewie Simpson; 01-21-2017 at 12:55 AM.

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