Edge refinement questions

S

Skane24

Joined
Jul 31, 2019
Messages
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Hello, ive been sharpening on a KME system, and I had a question, how much does it matter in terms of actual cutting performance/sharpness to remove all prior grit scratched on the bevel before moving onto a higher grit?

Is there any major benefit besides aesthetics to make it worth it to remove all previous scratches from the bevel?

I always fully apex with my coarsest stone, usually a 100 or 140 diamond, then go to 300, 600,1500, and then finish with green compound on a strop.

Thanks
 
So long as it's fully apexed, and if you're not concerned about a perfect mirror-like polish, there's really no reason to worry about removing all scratches from previous grit stages.

Now, even a fully apexed coarse edge can still be refined somewhat, beyond the coarsest stage. Going up in progression will also thin the apex width somewhat, which does improve cutting performance. It also helps to thin out any burrs left, which will make them easier to clean up. How far you go in the progression just depends on what you like in the particular character of the edge after each step. Test the edge in cutting, after each step, to see how it changes.
 
I usually get them very shiny, not quite mirror polish as that’s very time intensive. They shave, cut news print etc, some of them can whittle hair but not all. Still haven’t gotten it to cut paper towel cleanly yet unfortunately.

I seem to have more trouble with chefs knives than pocket knives.
 
Unless you are looking for a mirror polish then I don't think it really matters much. Some people prefer a slightly coarse or toothy edge. It is up to you and what works best for your cutting needs. A sharp knife, regardless of how it is sharpened, is still a sharp knife. Just decide when it is sharp enough for you and call it good.
 
Skane24 said:
how much does it matter in terms of actual cutting performance/sharpness to remove all prior grit scratched on the bevel before moving onto a higher grit?

Is there any major benefit besides aesthetics to make it worth it
Click to expand...
just search this forum for "toothy vs polished edge" and such, plenty of ideas expressed. I say sharpen it, use it, adjust as necessary. I have never chased mirrored edges, but watch a son enjoy the process and reflective outcomes.
 
DavidABQ said:
. A sharp knife, regardless of how it is sharpened, is still a sharp knife. Just decide when it is sharp enough for you and call it good.
Click to expand...
That just about sums it up perfectly. A sharp knife is a knife sharp enough for it to be able to do what the user needs it to do. They are tools, that is what they were designed as. :)
 
Technically, you should remove twice as much material as is needed to remove the deepest scratches before moving to the next grit. This is to remove the damage done by the last grit. I have heard this from two people over the years. The first spent 6 months studying grinding optics for one of the last Apollo missions and the other is the Science of Sharp. While I don't quite remember Todd saying to remove all that material before moving to the next grit he did talk about how there are fractures in the substrate that are about twice as deep as the scratches.

Personally, I just strive to remove most of the scratches from the last stone that are visible before moving to the next grit. For my sharpening setup that equates to 3 passes per inch of blade per grit so it's not like it takes much extra time to do it.
 
Diemaker said:
Technically, you should remove twice as much material as is needed to remove the deepest scratches before moving to the next grit. This is to remove the damage done by the last grit. I have heard this from two people over the years. The first spent 6 months studying grinding optics for one of the last Apollo missions and the other is the Science of Sharp. While I don't quite remember Todd saying to remove all that material before moving to the next grit he did talk about how there are fractures in the substrate that are about twice as deep as the scratches.

Personally, I just strive to remove most of the scratches from the last stone that are visible before moving to the next grit. For my sharpening setup that equates to 3 passes per inch of blade per grit so it's not like it takes much extra time to do it.
Click to expand...
What kind of setup do you have/use, if you don’t mind me asking. I appreciate the info.
 
It's all homemade, although that is my profession. The stones are EP Matrix and the guided sharpener is something I made several years ago. Here is a video of me sharpening a Maxamet blade with my setup.

 
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