View Full Version : Sharp knife got dull with Sharpmaker.

04-18-2013, 07:00 AM

Just got myself a Goko knife. Like this one.
http://www.This Site Not Allowed Here.com.com/gokogyuto210mm.html

Out of the box it was extremely sharp but not on the overall edge so I put it in my Sharpmaker Spyderco like with all my other knifes, carbons as VG10. After 30 or so strokes with both brown and white stone the whole knife got extremely..dull! I ran it with the 15/15 degree angle.

I noticed it sounded more than normal when i ran it over the stones and it lost lots of metal, more than I'm used to.

So, what's going on here and how to fix this? Shall I just continue with the sharpmaker. I have tried another 50 swipes but still I'm having a tough time getting through a normal paper compared to all my other knifes that is extremely sharp in my point of view.

Can someone who knows more explain what might have happened? :eyebrow:

04-18-2013, 07:45 AM
I am guessing the edge on this knife is thinner above the bevel than your other knives, so the pressure on the edge from the rods is multiplied due to the smaller surface area in contact with the stone. You have probably rolled the edge / bent the burr to one side. Use lighter strokes, and use the flat side of the stones not the corners.

Basically this knife is not designed to be sharpened on a device like the sharpmaker, and the sharpmaker is not designed for knives like that either. You can use it, but at the end of the day they are incompatible tools.

04-18-2013, 07:55 AM
With all the limitations of a distant diagnosis: as far as I know the Sharpmaker is a great maintenance tool, but not the best to create a new edge. I guess you didn't reach the very edge, remained just behind it, and accumulated debris on the very edge: a huge wire edge.
Use a marker to see where you're abrading steel. Don't switch sides until you've raised a burr.

04-18-2013, 08:02 AM
Oh, didn't know the Sharpmaker could be that destructive to a knife :O. I need to get myself a stone then. I have had my eyes on a King 1000/6000. Would that work better you think? At least when I have learned how to use it but I will train on some older knifes first.

I'll try the advice with lower pressure and just the flat side until I get a stone.

04-18-2013, 08:26 AM
When I check close the primary edge look like ****. It's like a saw. No wonder it cuts bad. How can it become like this when used on a sharpmaker or is it the knife that has problems? I try to understand what's going on.

I mean it's more dull that a 5 dollar knife at walmart and it gets no better no matter what I do.

04-18-2013, 09:06 AM
Zoom in on this picture and you'll see my problem. I only tried to sharpen it as described above. Also tried with extremely gentle force now too and only flat side of the stones. No progress :(


04-18-2013, 09:23 AM
FWIW, I'm afraid you haven't reached the very edge yet. You're polishing behind the edge. Couldn't you use a coarser grit?

04-18-2013, 09:39 AM
Did you zoom in on the picture and see the bits and pcs that comes off the edge?

Attaching more pics for reference.




And this is how the sharpmaker looks after 5 minutes of strokes.

04-18-2013, 09:51 AM
Use the Magic Marker Trick to see whether you've reached the very edge.


04-18-2013, 10:20 AM
IMO it looks like you're hitting the edge, so ease up the pressure! Only use the finest stones you have, on the flat sides. You either have a burr or chipping, both are made worse with pressure. Stropping on leather will remove / reduce the burr once you have got it to a reasonable size on the stones. The marker trick is a good idea though, just to be confident. Are you 100% sure the edge is getting worse?

The other thing is that the knife may have bad heat treat / missed being tempered somehow, but don't worry about that now, it's the least likely cause of your problems.

Benuser, if he isn't hitting the edge, then the edge would not be changing. Any debris would be able to be wiped off.

04-18-2013, 10:31 AM
The finest stones I have today is the white one on the sharp maker. But I have now ordered a King 1000/6000 too. It just feels strange to me that the Sharpmaker which works wonders on all my other knives including Carbon suddenly makes this lovely knife completely useless. I want to learn and understand what parameters are causing what you see on the pics. If it's me, the knife, the sharpmaker or a combo of everything. The feeling I get is that the knife cracks into pcs more than that it's me or the sharpmaker..

I will give it some more time with the white stones, flat side and as gentle as possible without dropping the knife. Still, I'm confused.

04-18-2013, 03:11 PM
are you using the flat side of the ceramic sticks or the corners? just curious..i find the flat sides allow you to move much more slowly in terms of sharpening.

i hope i never lose my sharpmaker. i love mine. mine is so old it comes in a pouch and not that black plastic box thing. the only knife i cannot sharpen with my SM is my vintage Case pocket knife..i think i need something more aggressive.

04-18-2013, 04:31 PM
I started with the basics meaning like 20 strokes on corners, 20 on flat. First brown then white stick. After this it became crap. Then some suggested to go with just flat sides and release on the pressure. Did so but still crap.. I will return the knife to be re-sharpenned because something must have been not OK from the start.

04-18-2013, 04:51 PM
Im with Benuser on this one. Looks like you are not sharpening the edge, but thinning behind it. And because you have done so many passes on each side, all that is left is a weak, fatigued wire edge that is chipping as you continue to flip the burr. I would try the sharpie trick for sure.

I dont know if you can say that something has not been ok from the start... even though it was not "sharp enough for you" the main problems you are seeing are from a sharpening attempt.

04-18-2013, 05:18 PM
According to the vendor, edge grinds are slightly asymmetric, which is probably an euphemism. Expect something like 12 degree on the right side, and some 18 degree on the other one. I guess he will be more than willing to put a decent edge on it for free, and refund your shipping costs, but there is no reason to blame the blade, and ask for its replacement. The Sharpmaker is a far from adequate instrument to change geometry as you've tried.

04-18-2013, 05:47 PM
Could it be the first pic in post no. 7 reflects the situation on the left side? In that case, deburring at 20 degree would solve - for the time being - your problem.

04-18-2013, 06:24 PM
Pull your knife through block of wood 5 times, then a piece of cork 10 times, sharpen again very carefully then strop on cardboard.

04-18-2013, 07:06 PM
I will agree with those that it appears you aren't hitting the edge. I would try sharpening at a slightly higher angle, but take care not to remove much metal to keep it thin behind the edge.

04-19-2013, 04:53 AM
My view..
1. Any tool used incorrectly will not get you the desired outcome.

2. A sharp knife must have 2 requisites.. a) teh 2 angles must meet b) thin enough.

alot of problems are around a) making 2 angles meet as we get burrs.. folded edges or when they are straightened out either a wire edge which I suspect in this case or a weak edge ( straight but weak) as the integrity of the edge metal has been compromised. Like a paper clip, fold it a few times adn it is weak.

3, You have to understand that being a new knife, the thinness shld be there and only it just needs to be straightened out or have the wire edge removed adn then refined. IN your case, i suspect that you did it so many times (50) your wld have removed the primary edge and teh new primary edge has receeded backwards leaving it thicker now. Thus a lower angle wld be required to set the secondary bevel and have a thin edge. Normally, a deburring on a new knife wld be say lightly 3 strokes per side ( assuming that this will break teh burr) adn teh following the alternate 3strokes per side to make it pointy ( refinement of the edge as I assume that once the burr /fold is broken, it leaves a rounded edge.

4. I prefer cutting strokes as that will force the burr/ fold to break rather than spine leading strokes as that will open/ unfold the burrs adn pray for it to eventually break. Light cutting strokes as we are dealing with a very thin edge no more than 0.04mm (?) so be gentle with it.

5. Deburring on a strop for me is just for" polishing" as one has to be very sharp that it is not a wire edge as you are folding adn unfolding the wire edge. THis even I prefer slightly thicker leather adn a little soft so that hopefully I get a convex edge ( I imagine so). THus it will be terminated at a higher angle.. better chance of breaking any folds and wire edge.

IN teh final analysis, its all about steel removal, how minute the amount you need to shave off and the 2 variables are your a) pressure b) grit. Then only can you determine what grit, adn pressure to achieve teh desired outcome.

I am certain, that the sharpmaker used correctly is a fine tool

You need to get stoned.. I mean use the stones as it wld be faster adn efficient to do so as it presents a bigger contact area.

Know the outome desired based on the present condition of the knife ( sharpness etc) adn tehn decide how much metal adn where on the edge adn then choose the correct stones, pressure adn angle of attack . Every stroke shld have a purpose adn not just blindly rubbing stone to teh metal.

The Burr is yr friend. it tells you that enough steel removal has been done and time to flip over., repeat teh process. After that is is just breaking off the burr adn refining the edge to make it pointy and no weakened or wire edge please..

have fun adn stay sharp..

04-19-2013, 05:37 AM
But what made the combination so destructive? Is it that the knife is very thin and the sharpmaker very aggressive meaning I should have done only like 5 strokes?

1. I used only the 15 degree angle and the papers that came along with the knife recommended 15 degree angle.
2. Sharpmaker instructions says around 20 strokes per side and stick which I started with. After this it became useless and the primary egg looked as the pictures. I hardly could come through a paper after this. No other knife have been dull using the sharpmaker in the same way. They get very sharp.

The knife has a White #1 core with stainless steel cladding if that could matter.

04-19-2013, 07:15 AM
I don't see that there is any need to buy stones for maintaining razor edge.

Use the sharpie on both sides.
Do 2 strokes on each side with either rods.
Post the pics.

04-19-2013, 07:27 AM
I don't see that there is any need to buy stones for maintaining razor edge.

Use the sharpie on both sides.
Do 2 strokes on each side with either rods.
Post the pics.
2 strokes? I don't get it. Sharpmaker recommends 20 per side and stick and that always worked very good for my needs until this knife.

When watching guys with whetstone they use it for like 5-10 minutes. That's a lot more than 2 strokes :)

Why would this combo require only 2 strokes to maintain a raizor sharp edge when all my other knifes need the 20+ and has no problems with it.

I will return the knife for sharpening to start with. I cannot use a knife that gets ultra dull when used on the simplest sharpener on the market. :(

04-19-2013, 07:31 AM
But what made the combination so destructive? Is it that the knife is very thin and the sharpmaker very aggressive meaning I should have done only like 5 strokes?

1. I used only the 15 degree angle and the papers that came along with the knife recommended 15 degree angle.
2. Sharpmaker instructions says around 20 strokes per side and stick which I started with. After this it became useless and the primary egg looked as the pictures. I hardly could come through a paper after this. No other knife have been dull using the sharpmaker in the same way. They get very sharp.

The knife has a White #1 core with stainless steel cladding if that could matter.

My thoughts...

counting strokes is just a guide line... as said above, depends on how thin and sharp ( condition of knife) After sharpening and is is only the wire edge ( the 2 angles have met adn folded adn also thin ), only a few Light strokes are required , slightly more than just the weight of knife.

Angles> I don't bother about angles. I only have high adn low, both are below 15 degrees.. One humanly low as best as I can to thin the secondary edge ( I suspect / guess abt 7-10 degrees) adn slightly or rather a notch higher for teh primary edge( cutting edge) which shld be abt 15 degrees hopefully. IF it is 20 degrees.. no harm done isn't it.. just not so sharp if I can tell teh difference, I bring is slightly lower.

Why 2 angles? IF you only sharpen at one angle say 15 degrees ALL the time, as the primary edge receeds upwards( towards spine) it becomes thicker. That's why I figured .. honing or sharpening as low as you can and the final angle slightly higher.. which in effect forms a micro bevel is teh way to go for me... Oh yes, if teh blade is so worn out a 15 degree is not going to make it too.. I have tio thin teh whole blade.. either on a stone or a 150 grit sandpaper...

Whatever angle you are using, the correct angle is that the primary edge must be in contact with teh stone if you are sharpening or deburring! that's all. IF you are thinning the edge ( secondary bevel) then the edge will not be in contact. For experiment, put knife flat on stone, you will fing that edge is not touching stone. Lift it up a bit till you feel that is just touching .. that is the correct angle...

So whatever specific angles that you are referring to.. the Japanese makers I believe are doing it free-hand anyway and we all want to beluieve that it is the magical 15 degrees!

IN the final analysis.. determine what you are trying to accomplish and do the needful and whatever works for you..

Figure this out and after a while, a few fondling moments with any blade, you will roughly know what to do to make her perform to your expectations..
Feel free to pm me anytime..

have fun and stay sharp....

04-19-2013, 09:07 AM
2 strokes?

Repeating strokes removes materials.
If you do 1 or 2 strokes, it'll help us see where you are removing materials from.
If you did 20 or 30 strokes, you will tend to rock your knife and sharpie won't show.
Here's an example.


After 2 strokes.

You can see that I'm grinding away at the middle of the sharpie and not the edge. This will thin the blade but will not sharpen the edge. In your case, you need to grind the edge. I'm afraid you are hitting the edge, causing the problem.

04-26-2013, 11:47 AM
The punk rocking knife from Goko is back to normal and man do I love it.


04-26-2013, 12:49 PM
congratulations! I hope that you did it yourself an mastered the knife

Stay sharp adn have fun..

04-26-2013, 01:19 PM
I have a sharpmaker which I've used successfully on all sorts of knives, but I've never used them on any of my Japanese blades. While I think you'll be able to use it, I don't think the sharpmaker is particularly well suited for the kinds of knives we talk about here. That's probably the main reason why you're having issues. My best guess is that you're using too much pressure and too many strokes and that you're not really hitting the edge squarely but more the sides of the core. Additionally, with the corners, you're concentrating ALL the pressure in a very small area which is probably the primary cause of the chipping and crumbling. Hard Japanese steel can be very delicate and may not respond very well to that kind of treatment. Your pocket knife will respond well, but not necessarily Japanese kitchen knives.

I'm going to offer what might seem an odd bit of advice. If you're going to continue to use the Sharpmaker, instead using waterstones, instead of following the "advised" angles, try the twenty degree setting on the knife. My guess is that you'll end up hitting the edge instead of the sides and you'll have better results and presumably a bit tougher edge. Again, I wouldn't start with the corners, but use the flats on the rods and use very little pressure. You just want to work the edge as if you're taking a microscopic thin slice from the rod. Just keep the blade square to the countertop and let the weight of the blade do the work. In this case, ignore the instructions that came with the sharpener and do what the knife requires not the other way around.

My best advice is to get some waterstones and learn how to sharpen with them, but if you're going to use the Sharpmaker, you're going to have to adapt your approach to the demands of the knife.

04-26-2013, 02:28 PM

some people say that Japanese knives you shld use a rod...

My view... I am not saying that they are wrong.......its all about the grit on the rod. IF your last final grit is 10,000 grit and you hit on a rod that is rated say 800 grit, that will be your final edge.! no point lamenting that the silky feeling is gone!

No matter how sharp your knife is after cutting adn hitting the board, first level of degradation is a fold/ burr. Either you straighten it out and thus leaving a wired edge which will eventyally break anyway OR cut/ break it off . IF it is the latter and the edge is still thin, a few additional strokes will further make the edge pointy as after it breaks off, i assume that it will be slightly rounded.

At times yuo want to hit the edge on the rod so as to thin the edge to maintain the general thinness of the edge. failing which after a few session you get a thick edge .. naturally

You are spot on " you're going to have to adapt your approach to the demands of the knife." I use the rod of appropriate grit mainly for deburring. I own a few rods, 400 diamond, abt 800 grit steel adn 1600 ceramic rod. Also own a "jewelstik" diamond rod.. 3 grits on 1 rod.

have fun

05-06-2013, 11:30 PM
I would never use a SharpMaker on any Japanese knive, nor use a western steel on one. The edge is too thin and too brittle, you will simply snap it off, leaving a jagged, rough edge that will not cut.

You can do the same thing by rocking it back and forth while chopping veggies on a wooden board, too -- NOT a standard western style knife.

I will second the advise to get a set of waterstones and learn to use them if you want to use Japanese style knives, and spend some time learning to use them as they are designed. If you don't, you will be spending a very great deal of time sharpening them and much less using them, as that steel is VERY unforgiving of any mistakes. Razor sharp and a joy to use when sharp, but very easy to damage that thin, hard edge.

Just the nature of the beast.


05-07-2013, 12:35 AM
I think the Soso has solved his problem, so let me go off in a tangent a bit.

I haven't owned or used a steel in a couple of decades,
but there is pretty popular information out there (or perhaps misinformation)
that they don't remove any steel. Here's an excerpt from wiki:

The naming is often a misnomer, because the traditional "honing steel" is not a hone at all,
i.e. its function is to displace rather than to remove metal along the edge.
Whatever the actual mechanism is, I remember my honing steel doing a fine job
of increasing the cutting power of my dulling knives.
In addition, since they don't actually remove any material,
any damages resulting from appropriate uses should not be permanent.

When I sharpened kataba-style knives for other,
I'd occasionally give the advice like the following:
Use honing steel to lightly realign their edges if they get dull.
If honing steels don't fix it, bring it back to me.

Was I just spewing nonsense?
Has anyone done some serious damage to their kataba or noticed them getting more dull?

I know it sounds ludicrous, but some people really just don't like sharpening things.
(In the same way I don't like shopping.)
And it seems like steel is just a nice way to maintain good sharp edge.

Nevermind, I found the answer from another post.

99% of grooved steels are junk, they can only (at best) rip the edge apart to offer some edge teeth to aid in cutting performance but when used on hard/thin edged Japanese knives the pressure exerted easily cause edge chipping.

A really hard & smooth steel would be a decent option for these knives (something like the slick made by F. Dick) but this only works OK since you need to use it often and catch the edge before it degrades too far.

A smooth ceramic rod, and to some extent a very fine diamond rod, is a compromise between those two above as they scrape the edge to provide some teeth but (in the case of the ceramic) it's more forgiving as to not chip the edge and both will work a lot longer than a smooth steel will.

In all cases I find them inferior to a nice strop but that's my own personal tastes talking, there's really nothing wrong with using a steel/rod if it's used correctly.

I should learn to use the search option before posting.