Am I On Track?
- This topic has 26 replies, 6 voices, and was last updated 08/08/2019 at 3:26 am by
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Richard, learning how to sharpen knives to a sharp polished edge is a learned process through repetitious experience, time, effort and attention to detail. That edge looks pretty good. Not as good as you’d like to see. Also not so bad, IMO, to go back and do it over again. To not waste your time, effort and knife steel I’d recommend you strop this edge and enjoy using the knife.
The next time you’ll spend more time with each sequential grit stone. You’ll watch closer during the process to make sure you’re removing all the previous grit’s scratches. You’ll double check to verify your guide rod angle settings are precise and consistent, with each grit change. There are a lot of things to pay attention to and to keep track of. Each time it gets easier and more consistent. The previous efforts are not lost. Each touch-up takes advantage of this established bevel and improves it, as long as the knife is positioned the same and bevel angle setting is the same.
The next time you’ll get it closer to what you’re looking for. In the mean time use it and enjoy it.
Another problem we face is each knife we sharpen we do it a little better. So we tend to expect a little better results from our selves and set our own bar a little higher.
Marc
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Marc’s advise is good, but I’ll offer an alternative option.
If you’re dead set on having a highly polished finish this time around I suggest going back a few grits perhaps to the 800 or so and then working your way back to where you are now. Work with extra care and attention to detail. This will get you the results you’re after and you don’t have to settle just to save a bit of steel and time.
Thanks to both of you for the great advice. Maybe I’ll just leave this one as is and instead practice on an old kitchen knife. And since we’re on the subject, I looked around the forum earlier and couldn’t find anything on it. My method on a re-profile is to start by scrubbing using my 100-grit stone until I feel a burr and then do the same to the other side all the time checking consistency with my microscope. By scrubbing, I mean an up and down motion traveling east and west on the blade. Once the bevels match, I then use the same stone and begin my upward strokes and using the microscope continually until the vertical scratches are gone from the scrubbing. I then advance to the next stone. My question is, how far do I go before I cease to scrub and just use the upward strokes? Today I stopped at the 600-grit and just stroked it the rest of the way beginning with the 800-grit.
Richard, I use an up-down-up-down scrubbing stroke with every stone I employ as the beginning stroke to set my bevels with that grit. (Except lapping films and strops when I only use a edge trailing, up and off stroke). This is my preferred method. My technique.
Your preferred method, your technique, is an individual preference developed over time with trial and experience. There is not one method that is necessarily wrong or correct. It’s a results driven technique and your preference. Try different methods and see what yields the results your looking for.
I can suggest that you do it the same way several times before switching it up. If you try something different every time, you won’t do it any one way long enough to refine the method to achieve the best results you can doing it that way. When you see what you get after several tries then change something up to see if it makes a difference; an improvement.
Over time you’ll find what you like and put it all together into your own technique. That technique you’ll then refine, over time.
Marc
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Hi Richard! Since I have learned from Marc my advice will sound familiar..
I will do the same up and down strokes with each stone to set the bevel and remove the majority of the previous grits scratches. Then I switch to short (3-4 inch long) edge leading (down and away) over lapping strokes (assuming a chefs knife since I have no folders). So starting at the heal and going to the tip one side at a time. This will help refine the edge before moving on to the next grit. Once my bevel image shows all new scratches of the current grit, all going the same direction (slanted towards the tip) and no red marker left behind when I apply it and make one or two complete pass, I move on. Again, this is personal preference and you will figure out what works, just takes a bunch of knives and a good bit of time!
One thing to point out, the 100 Grit stone takes a long time to really break in. Mine still leaves deep scratches if I push too hard or go to close to the end of the stone where it has not been used as much. Once you get a dig in there from a high spot you are not going to get it out without removing a lot of metal.
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Gee, I just spent the better part of an hour writing a nice comment for Richard. As I hit the “Submit” button, we were hit with a heavy downpour and I got kicked off the forum – no longer logged in and the comment lost in the interstellar beyond. Rats. It was a good one, too.
Gee, I just spent the better part of an hour writing a nice comment for Richard. As I hit the “Submit” button, we were hit with a heavy downpour and I got kicked off the forum – no longer logged in and the comment lost in the interstellar beyond. Rats. It was a good one, too.
At least you didn’t accidentally close the window.. worse when you do it to yourself.. just a little!
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Richard…
Gosharootie, I really ought to reassemble my thoughts here… Oh, yeah…
I wanted to make a couple of points. First is that I eschew (cool word, eh?) use of the lower grit stones in the edge-trailing direction. I’ve seen too many cases of damaged apexes, sometimes too severe to remove with the next finer grit. The damage can be either chipping (as is the case with particularly hard steels and low angles) or breakage caused by weak areas in the steel at the very apex. In either case, the damage is lessened or even eliminated by changing to edge-leading.
If you think of a single grit particle plowing a groove into the face of the bevel, the width and depth of the groove are limited by the mechanical resistance of the steel on either side and in front of that particle. As that particle approaches the edge, there is a sudden drop-off in the resistance of the steel in front of it. The analogy of a plow is appropriate, and the hard ground is the steel resisting the advancement of the plow. If it suddenly comes to a rut or other ditch crossing its path, it will break free, leaving an opening wider than the trench it has left behind it. The harder the soil, the greater the breakage.
I’ve settled in to a discipline of alternating direction with each grit change – down and toward me for the first grit, then down and away from me with the next. My current handles are all made from blank handles, so each is red on one side and white on the other. I assigned red as the coarser grit and white as the finer. Red is always down and toward me; white is always down and away. This greatly simplifies things for me, so I never have to remember which was which. And I never accidentally take an edge-trailing stroke.
Yes, I do use scrubbing strokes, but never with coarse grits if I am near the apex.
Whether you use edge-leading or edge trailing strokes, and whatever grit you are using, you should know that as you are erasing the edge damage from the previous grit, you are leaving some degree of roughness at the apex, which is dependent on the pressure, the steel, and the grit you are using. That roughness will need to be removed by the next grit. Since the edge roughness is coarser than the scratch width and depth, it will take more effort to remove than it takes to erase the scratches on the face of the bevel.
To see this in real life, look at the side view of the edge of the knife you are sharpening with your ‘scope on high power, maybe 300X+. While the bevels at 1000 grit are nice and smooth, the apex looks like a plowed field.
The second point I wanted to make is that your photo shows evidence of scratches from the previous grit at the edge. This means that whatever effort you expended on that last grit may have served to polish the bevel, but did nothing to refine the apex.
As you refine your techniques, you’ll find that this sort of errors will be easier to recognize. On my rigs, that degree of error can be seen with less than 0.15 degrees of change in angle. Meanwhile, it is an indicator that you should check the results of each grit with your microscope. You might find it necessary to make minor angle corrections – or you might find that something else is happening, like a loose micro-adjust screw. You also might find that a particular stone causes a particular angular error – Perhaps it’s not seated properly in its handle. And/or you might find that flipping that handle end-for-end causes another angle change. If so, try to solve that problem. Maybe you’ll want to make a pre-defined micro-adjustment each time you use that stone.
Where the error is recognized and corrected, you should need to only make a small adjustment to erase those scratches. Probably only 0.2 degrees.
The first guy who accuses me of verbosity… is probably right.
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Tom,
With edge leading, wouldn’t the particle crashing down on the edge cause the same damage/rut due to the small resistance of steel at the edge of the edge? Whether you push the plow or pull the plow the science/physics should be the same.
Ed K.
In either case, the damage is lessened or even eliminated by changing to edge-leading.
If you think of a single grit particle plowing a groove into the face of the bevel, the width and depth of the groove are limited by the mechanical resistance of the steel on either side and in front of that particle. As that particle approaches the edge, there is a sudden drop-off in the resistance of the steel in front of it. The analogy of a plow is appropriate, and the hard ground is the steel resisting the advancement of the plow. If it suddenly comes to a rut or other ditch crossing its path, it will break free, leaving an opening wider than the trench it has left behind it. The harder the soil, the greater the breakage.
Richard, the plan is to overcome the first scratch pattern, totally, with the scratch patterns of each subsequent grit with their smaller, shallower, and closer together scratch patterns. This is why some sharpeners utilize a direction change with each grit. By this I mean start by working the stones across the edge from knife heel to knife tip. The next grit utilize a direction of stones across the edge from knife tip to knife heel.
This lays the sequential scratches in the opposite slanted directions, making it obvious to see the previous grit work. The idea is to do enough effort with each grit to totally obliterate all visible remnants from each previous grits. It’s important that the knife position and the stone/guide rod angle settings are verified as correct or corrected with each grit change to assure totally obliteration. The results of your efforts can be visually determined using a lighted magnifying device of your choice.
If you think your efforts look “pretty good” then spend more time till it appears really good. You can not do too much, IMO.
If you have followed the sequence with attention to detail, each finer grit will obliterate and smooth the steel’s surface so that when you get to the finer grits like the ceramics you’re really looking now to smooth the surface by removing the scratched surface steel and in turn making for an extremely sharp edge.
Then the strops really polish and slick off the surface to bring out the sharpest feel.
By the time you’re up to the ceramics, ideally there are no remnants of the previous cross direction larger scratches. If you see them you’re best remedy is what Organic previously recommended to step back down a grit, or two or three till your using the grit where you failed to sufficiently remove the previous scratches.
For me every knife is a new separate challenge. Just because I did it very well the last knife I still have to apply the same kind of effort and attention to detail this knife. But this knife due to it’s steel, it’s profile and it’s condition may be totally different and the the level of effort needed may be increased. The practice, though, is the same. It just may take more time and effort….or maybe less. It has never become routine and predictable in my experiences. It always requires “that certain level” of commitment and vigilance.
Just to add one more twist…the direction the stones travel or walk across the knife length, heel to tip, or tip to heel, and the direction the stone crosses the edge, edge leading, that is down and onto the knife edge, or edge trailing, up and off the knife edge are seperate things that are used together, simultaneously, to make up your utilized sharpening stroke.
How much of the knife’s edge length you address with each sharpening stroke is up to the sharpener. My preferred method is to work the knife edge length in smaller portions and ultimately blend the effort before moving onto the next grit. But I sharpen mainly kitchen/chef’s knives. Others may prefer to sharpen across the full knife’s length in one continuous stroke. It’s on you to try different methods. Then tie them together into your personal sharpening technique.
Marc
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Thank you so much for that detailed feedback. I’m aware that it’s going to take me awhile to figure out all the tricks of the sharpening trade but I’ve got nothing but time. Regarding the photo I sent in, that was one of my questions. That was my final bevel, a 15 degree using the 1600-grit ceramic stone but like you said, the apex is showing signs of the original scrubbing. I’m wondering what my next move should be to smooth that out. Do I need to just continue stroking with the same stone or contemplate another technique?
Just adjust your angles by about +0.2 degrees, or about two-thirds of a turn out on the micro-adjust screw. All of the stones I use seem to match angles beautifully, except for one of my 1000-grit stones. It measures almost 0.2 deg. higher than the previous grit . If I recall correctly, that probably is caused by a 0.020″ difference in the mounting height of that particular platen. One annoying complication is that it throws off the measurement when I want to reset the angle for the 1500 grit on the opposite side of the same handle. Of course, this is because I place the angle cube on the 1000-grit surface. Maybe if I put it on the rod itself…
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