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Beyond the 1000/6000 suehiro combination stone, what's next for razor sharpness?

post #1 of 14
Thread Starter 

Hi y'all.


I've only recently started sharpening with water stones (Suehiro 1000/6000 combination stone) -- my total experience is very little, but I'm willing to put in time to practice.   I don't have to have instant results with whatever I move forward with, but do want my cooking knives (Shun elite gyuto, Wustof classic chef's and boning and paring.  Probably a Sakai Yusuke in my near future.)  


I started trying to sharpen these with a combination oilstone and had average / not so hot results.  I probably spent 5 or 6 hours in that arena, then was persuaded to try a 1000/6000 combination stone.  I'm having much better results and am pretty happy already with the edges I'm getting.   I've probably spent 6 hours sharpening using the combination stone (and have sharpening anything in the house with an edge not bolted down...)


However, being the obsessive that I am (and who among you will cast that first stone?) I admit to wanting a scarier, sharper edge.  I would like an edge that can chill my guts from just my mere glancing at the knife.  Across the room.  That scary.


I realize I am probably mostly limited in this goal by practice at this point.  OK, I will continue practicing.


However, in addition:


Do I need a stone between 1k and 6k?  I see a lot of 1k, 3/4k, 6k or 1k, 2k, 5k progressions...Would this give me a sharper edge?


I also hear that some stones (blue aoto 2-3k) are not appropriate for sharpening Western knifes.  Can somebody enlighten me why this is (or isn't) the case?  Are there stones that would or would not do well for sharpening some Japanese, and some Western?


Should I instead consider adding something finer like a finer finishing stone or a strop? 






P.S. Also finding that the fine edge on my Shun is very quickly -- like < 1 week -- losing its scary sharpness.  I confess to be using a edge-grain bamboo cutting board.  Looking for something softer as we speak.  But perhaps another area to investigate.  Somewhat an aside...

post #2 of 14
A few remarks if you don't mind.
A Wüsthof should be sharpened on a relatively coarse stone. I use a J400 or corresponding sandpaper with German or French stainless, and a Chosera 800 for deburring. With soft stainless any refinement is counterproductive.
Proper sharpening doesn't take very much time. If it does, your movements get less precise. Back to basics, please. Raise a burr, chase it, get rid of it. As a beginner you shouldn't even think about touching the 6000.
The Shun is a special case. Its core is made of VG-10, a great steel, but very hard to deburr. The poor retention you've noticed has to do with a wire edge, I guess. For the time being you may add a microbevel to be sure you've eliminated the burr. A few strokes at a higher angle on the 6000 should give a workable edge.
post #3 of 14
Thread Starter 



Thanks for your reply.


The Shun elite is SG2, not VG10, FWIW.


So I do notice a huge difference in sharpness between the 1000 (which feels sharp but rough) and the 6000 (which feels very sharp and smooth.) Should I really not touch a 6000 until I practice more?  I think I'm getting fairly good results, though certainly not perfect...


Thanks again,


post #4 of 14
A huge difference between the 1k and 6k shouldn't occur. The 1k should be scary sharp, and not rough in any way. The 6k provides a slightly thinner and much more polished edge. The difference will be the most obvious in push cutting.
If the 1k edge is not OK working on the 6k won't correct it.
The apparent sharpness of the 6k that doesn't last is an indication of a wire edge, a thin upright burr on the apex, extremely sharp but that will soon break off.
post #5 of 14

try to stick with what you've got first and then strop with newsprint. look for videos on youtube from murry carter so you'll find out how he does it. most of the time, you have to get yourself more familiarized with your stones and your knives first before you should move on to other things. if you don't, you won't learn much. imho. 


anyway, you'll still need a stone to thin your knives eventually. get a 320-500 grit japanese stone and you're good for a while. =D

post #6 of 14

The Suehiro 1K/6K is a decent -- but not very good -- stone.  Outside of it being a combi stone with the usual combi stone issue, it doesn't hand a lot of abrasive in the matrix, which makes it a bit slow;  because the clay matrix is what it is, it dishes quickly and needs frequent flattening.  The 1K side may need flattening as frequently as every knife if you soak the stone before sharpening and use a lot of pressure during.  


You don't need an intermediate between 1K and 6K.  It seems you do need are better understandings of the sharpening process in general, what you're doing in particular, and better control.  But I can't be sure until you tell me what think is going on. 


Grit numbers don't mean what you seem to think they do.  In terms of how fast a stone cuts, how well it polishes out scratches left by the previous stone, how easily the next stone will handle the scratches it leaves, and how well the edge will work for a particular knife or task, the numbers aren't consistent from one manufacturer to another or even from a given maker's line to another line. 


The grit number tells you enough to know the stone's basic position in the continuum which goes from coarse to ultra-fine.  Coarse stones are used to "profile" or repair; medium/coarse stones are the most popular stones and they're used to begin the sharpening process; medium and medium/fine stones refine the edge, with medium/fine stones leaving something of a polish; and fine through ultra-fine stones polish, but don't do much to make an edge.  


Within each range there are any number of stones which work better, faster, more easily, need more maintenance, and so on.  There are a few bargains, but only a few.  As a rule, you get what you pay for. 


The 1K side of the Suehiro is medium/coarse.  The 6K side is medium/fine.  The 6K will do a decent job of following up the 1K and the gap between them is not so great that an intermediate stone will make your job any easier.  So unless you're looking for a stone which is a better finisher for your Wusties, I wouldn't bother with adding another stone.  


It's something of a waste of time to put a lot of polish on a knife blade which doesn't have a lot of "scratch hardness," because the edge will lose a great deal of its polish as soon as it's used to cut something fibrous.  Your Suehiro 6K is a little finer than you'd want from a Wusthof, but as long as it does the job there's no reason to run out and buy a new stone.  Or at least not yet.  


From your description of what's going on with your Shun, the most likely explanation is that you're creating a "wire edge," and not completely deburring.  I think Benuser spotted that, and Franz might have as well; but neither was explicit. 


FWIW, deburring a wire isn't a big deal with VG-10 (which has its own set of problems), but is more of an issue with SG2 and other high-toughness PM (powder metallurgical) alloys.  


I think sharpening is best understood using what I call the "burr method."  That is, sharpening can be divided into three basic parts:  Profiling; Sharpening; and Polishing.  And sharpening itself can be further divided into creating a burr (or "pulling a 'wire'"), chasing the burr, and deburring.  If that doesn't make sense to you, say so and I'll break it down so it does.  Once you've got some idea of how an edge is created, and when and how to move from one phase to the next, everything will get a lot easier.


Your goal of extreme sharpness is very achievable and not very far away.



post #7 of 14
Thread Starter 

Thanks, all, for the feedback.


So let me perhaps back up a bit and start with what I'm trying to achieve.  Then perhaps where I am will be more clear.


I had the Shun sharpened by Dave Martell, who put a great edge on it.  Within a little over a week or so, I noticed push cutting was no longer as effortless.  I suspected maybe the bamboo cutting board is dulling the knife.  I cook about 8 hours / week on average.   I'm not a "hard chopper" so don't think I'm pounding on the edge, but there it is.    


So my goal with respect to the Shun is to just maintain the existing, very nice edge over time.  Eventually, I'll need to resharpen but not yet.   All I've done with the Shun is to that effect -- an attempted touch-up with the 6k stone.  No use of the 1k stone on it.  The result I got seemed better for a day or two but did not last.  This is the primary issue I'm trying to resolve right now -- how to touch up the Shun in order to maintain razor sharpness.



Longer term, I'm just trying to improve technique to get the best edge I can and maintain it....No surprises there. ;-)



Thanks again!


post #8 of 14
Thread Starter 

By the way, BDL, with respect to your questions on understanding the burr method, chasing the burr, difference between sharpening and polishing: yes, that makes sense and I do believe I understand.  


As somewhat of an aside, when I said that after the 6k, the knife felt much sharper, I meant that I felt less resistance during a push cut -- perhaps due to a more polished edge, yeah?  Not the same as sharpness, but effectively, it would feel like it, right?  Less force required to get through food == greater effective sharpness, if not actual sharpness...etc.  Am I correct here?




post #9 of 14
If the result of your touch up attempt didn't last for more than two days that was most certainly a wire edge, as BDL and I assumed.
post #10 of 14
Thread Starter 
ok, good to keep in mind. I'll see what I can learn about correct de-burrng and go from there.

post #11 of 14
I will try to explain. With use, the Martell edge got some damage, especially on the bamboo board. Call it fatigued steel. See it as debris that has to be removed. You didn't remove it, just replaced it into the wire edge, I'm afraid. So, go to the 1k side and clean up. Before that remove the wire edge with a few very light 80 degree strokes. Than you should be able to restore a decent edge.
post #12 of 14
Thread Starter 
By the way, some clarification: when I say I notice a difference in sharpness in a few days, I don't want to imply that it's dramatic, just noticeable.

Would you say that with a proper touch-up, I should not be experiencing a drop off (even if somewhat minor) within a few days? Perhaps this basic assumption is flawed....if so, your correction on this point would be very appreciated...

Is the 6K the right stone to use for such a touch up?

Also, if I may clarify some confusion I have regarding chasing a burr: does one continue to chase a burr during the later (edge polishing) phase, such as when using the 6k or does the technique change at finer grits? I've seen a variety of videos (though will check out Murray Carter's for sure) and it seems that the number of espoused techniques are the same as the number of sharpeners. :-)

Thanks for indulging my many questions. This is a big help.

post #13 of 14
It's true: some say there is no need for raising and chasing a burr with higher stones, ASSUMING IT HAS BEEN DONE ON THE COARSER ONES BEFORE.
In your case this condition hasn't been fulfilled. You started with the polishing stone, moving some stuff to the apex without verifying if the bevels actually met - they don't, believe me.
You don't want to touch to Martell's edge, but it isn't there anymore.
post #14 of 14

can't expect a knife to stay as sharp as it was freshly off the stones. it will usually drop a bit then plateau for a while then slowly drop in performance. 



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