sharp coarse edge

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Vicv

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Aug 22, 2011
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Looking for tips on getting a sharp coarse edge. I know from tests done by Ankerson and and Phil Wilson and such a good 4-600 grit edge will cut more aggressively and usually last longer. Problem for me is unless I go to at least 1k grit I can't get a smooth sharp edge. Like I've never gotten an edge to cut paper without tearing staying at that low a grit. And that's with removing the burr and stropping. It doesn't matter whether I use bench stones or the Lansky/Gatco. My preferred method a belt grinder no problem but the loaded polishing belt really fines the edge regardless of the last belt used. But if I go from a 600 stone to a 1000 even just a few passes I have a very sharp edge. I find this problem especially prevelant with the guided systems. Never have tried an edge pro/wicked edge though but it should be the same
 
It's not the tools.

In your process you are not doing something consistently enough except when you revert to the method that works. With good technique and a decent knife you could get a shaving sharp edge from a 120 grit diamond plate. Light strokes are key to refining the burr and creating a sharp edge at any grit, focus on what you are doing and try to find subtle flaws in your technique.
 
Ya. I know it's not the tools. Just practice just wondering where I'm going wrong. The lansky/gatco seems pretty straight forward yet I've never gotten real good edges on it. Must be more to technique then I think. I actually get better edges by hand but that's probably more to do with much better stones. It could just be a burr still but at the end I used very light pressure and alternating strokes and I felt no burr after. Then 5 strokes on the 1k ceramic and it was sharp. Well as sharp as I can get these particular Chinese made steak knives anyway
 
Just data points ...

With my Sharpmaker's CBN rods (~400), I can get edges to just slice phonebook paper though not 100% smoothly.

With my DMT Aligner's Red Fine stone (~600), I can get edges to slices phonebook paper easily.

But it did take practice to do it consistently.

Haven't tried anything coarser but that'll be my next challenge. ;)
 
OK it's been a couple years since I used the lansk/gatco but I know I had the same problem before
 
Vicv said:
Looking for tips on getting a sharp coarse edge. I know from tests done by Ankerson and and Phil Wilson and such a good 4-600 grit edge will cut more aggressively and usually last longer. Problem for me is unless I go to at least 1k grit I can't get a smooth sharp edge. Like I've never gotten an edge to cut paper without tearing staying at that low a grit. And that's with removing the burr and stropping. It doesn't matter whether I use bench stones or the Lansky/Gatco. My preferred method a belt grinder no problem but the loaded polishing belt really fines the edge regardless of the last belt used. But if I go from a 600 stone to a 1000 even just a few passes I have a very sharp edge. I find this problem especially prevelant with the guided systems. Never have tried an edge pro/wicked edge though but it should be the same
Click to expand...

Part might depend on what you expect or mean by a 'smooth' sharp edge. Most edges up to ~ 600-grit or so will usually retain at least some 'toothy bite', while still quite capably being wicked-sharp, even shaving-sharp; they typically wouldn't be described as 'smooth' however. If the goal is a 'smooth' edge, meaning less toothy, then something higher in grit is likely what you need anyway. The 600 and 1000 hones from the Lansky set are ceramics, and it makes sense that you're not seeing the 'smoothness' come into the edge until using those hones; they'll tend to polish a lot of the teeth out of the edge, like ceramics typically do.

As Jason mentioned, it mostly depends on a much lighter touch to produce shaving edges from coarse or very coarse hones. You mentioned in your other post that you get better edges by hand, using different stones; might be a clue in that. The Lansky & Gatco can work well, but the system as a whole can be somewhat awkward and actually impede good technique a bit, being limited by the narrow & short travel of the hone in the fixture. I used both systems, as well as a DMT Aligner, and there came a point where my hands wanted to assume more control, and it started feeling as if the clamped setup was holding me back a bit. None of the clamped systems afford the same fluidity of stroke as could be excercised on a bench hone or other freehand method, and that lack of fluidity can get in the way when attempting to refine an edge.


David
 
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What I meant by smooth I guess is cutting a piece of paper and having it smoothly cut without tearing or feeling catches in the cut at it moves from heel to tip. It just feels coarse and not very sharp. The problem with free handing is my most course stone in a 1k Waterstones. I have a 220 naniwa ss but there's something wrong with that stone. May even be a fake as I bought it on the Bay years ago and I've lapped at least 3mm off the stone and it still won't cut steel. Rough texture but my 1k king is 10 times faster so that was why I was trying with my gatco stones
 
Vicv said:
What I meant by smooth I guess is cutting a piece of paper and having it smoothly cut without tearing or feeling catches in the cut at it moves from heel to tip. It just feels coarse and not very sharp. The problem with free handing is my most course stone in a 1k Waterstones. I have a 220 naniwa ss but there's something wrong with that stone. May even be a fake as I bought it on the Bay years ago and I've lapped at least 3mm off the stone and it still won't cut steel. Rough texture but my 1k king is 10 times faster so that was why I was trying with my gatco stones
Click to expand...

Sounds like most of that is likely due to coarse burrs (snagging/tearing/catching) and/or the apex not quite thinned as much as it could be ('feels coarse and not very sharp'). That's the main hurdle to get past in using coarser stones, and is something that can improve with developing a lighter and more consistent touch on the stones.

Jason should be able to give you some great advice on your waterstones, if any of them are contributing to the troubles.


David
 
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Vicv said:
Looking for tips on getting a sharp coarse edge. I know from tests done by Ankerson and and Phil Wilson and such a good 4-600 grit edge will cut more aggressively and usually last longer. Problem for me is unless I go to at least 1k grit I can't get a smooth sharp edge. Like I've never gotten an edge to cut paper without tearing staying at that low a grit. And that's with removing the burr and stropping. It doesn't matter whether I use bench stones or the Lansky/Gatco. My preferred method a belt grinder no problem but the loaded polishing belt really fines the edge regardless of the last belt used. But if I go from a 600 stone to a 1000 even just a few passes I have a very sharp edge. I find this problem especially prevelant with the guided systems. Never have tried an edge pro/wicked edge though but it should be the same
Click to expand...


Reprofiling a dull factory edge with Sharpmaker CBN rods (400 mesh). If you don't want to see the whole reprofiling job, the cutting demonstration is at 14:19.


[youtube]ywogvxTQGXk[/youtube]
 
One can easily get a non-tearing cutting edge (whisper slicing paper edge) coming off a 320 grit Norton India stone. Just by patiently soft working it. DM
 
https://youtu.be/j032eLxxhzc

Heres a video i did with the Atoma 140. I have used this technique with success on stones as coarse as the Nubatama 24

Very light strokes and burr removal are key.
 
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OK thanks everyone. So as I thought it's all due to my technique. I'll have to work on that. I thought I was using very light finishing strokes but obviously not light enough or not enough of them
Magnanimous: your video didn't show up for me

Sadden: that was awesome with a 140 atoma. If you can do that then I can get a 400-600 ao stone to work
 
I like to use a super light micro bevel once I get the burr removed. Then strop on plain dry paper wrapped around another coarse stone at the original angle.

Keep in mind, when it comes to coarse edges there's a lot of variation possible. I once whipped up an edge so coarse, when pressed into a piece of paper on a laminated desktop, it didn't cut the sheet in half. When I picked it up it was stuck to the edge - impaled on the fine points of the edge - could been seen sticking out the other side. And this would still shave some arm hair.

Most of the time, if a real coarse edge will draw cut cleanly across the grain on newsprint right to the other edge and still shave some arm hair, you're doing fine.
 
Nice video Magnanimous. From what I understand though the brown sharp maker rods aren't exactly coarse and leave about a 1k waterstone edge you're getting quite refined at 15u
 
Vicv said:
Nice video Magnanimous. From what I understand though the brown sharp maker rods aren't exactly coarse and leave about a 1k waterstone edge you're getting quite refined at 15u
Click to expand...

I'm using the diamond rods in the video.
 
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