Snagging Belly Line

With some great information from several members in another thread I made great improvement in my free hand water stone sharpening. I've run into a new snag however (pun intended!)

I'm now able to produce an edge on my hunting knives that, by my standards, is very sharp. My personal sharpness standard for a hunting knife relates to skinning and quartering an animal. I want to be able to run the blade up the underside of the skin, and easily slice through the leather the way a nice sharp pair of scissors will cut through paper without moving the scissor handle up and down.

99.9% of my blade is that sharp. When I test them on newspaper or magazine paper, all three of them consistently snag right where the blade transitions into the curvature of the belly. To clarify, I mean the part where if you hold the knife such that you are looking at the broadside of the blade, the apex of the blade runs flat for a time beginning at the handle, extending toward the point. But right where it starts to curve upward and taper into the tip; the beginning of the curve of the belly line.

I'm working with three bark rivers. One Huntsman in A2, one Fox River in Elmax, and one Bravo 1 in 3V. All three are convex grinds. I know it has nothing to do with specific geometry or steel because all three of them suffer the same problem.

I really wish I could supply pictures but my microscope is not digital, and I cannot take pictures with it. I'm working on getting one (Any suggestions anyone? I don't want to spend a lot of money if possible). I thought perhaps in the meantime this problem might ring a bell, maybe this is a very common problem for rookies with a known cause?

Clearly it is an issue with my technique. When I look at the snag point under the scope I can see a small section of what appears to be a very fine burr. Very small; under 20x it is barely visible. I've thought through this many times and I've kind of hit a mental block.

Am I applying too little pressure to take the burr off? But that would contradict the burr formation in the first place I think. If it's only forming in one small area and nowhere else, I almost have to conclude that I've applied more pressure there than anywhere else, otherwise how would it have formed at all?

I've tried very light stropping with fine white compound, at a very slightly elevated angle, with pressure less than the weight of the knife, to try to get the burr off. I've tried pulling it through a wood block. But the burr remains.

I've seen a post by Cliff where he says it's best to not let the burr form at all. Do I need to practice with the 1k grit stone and never progress up to finer grits until I can learn how to not let the burr form? Or is a tiny, tiny burr a reality that a rookie needs to learn to deal with, and perhaps I should focus more on learning effective ways to remove it?

Sorry for the long post. I've found a new passion it would seem, and I'm a little disappointed at being stuck on this. Thanks for reading.



Edited 2 time(s). Last edit at 07/25/2018 08:25PM by ognennyy.

I don't know a lot about camera microscopes, but Joe Calton just did some videos on youtube on the one he has. It might be worth looking at.

With regards to the problem, I think that transition is often an issue as you learn to sharpen....and even later. I still struggle with really curved blade bellies at times. The curvature makes it hard to maintain the edge angle I think, especially since you generally have to raise the blade (increasing it's distance from the stone) on the curvature.

Do you have any diamond stones, or Spyderco ceramics? You want a hard stone that cuts well and doesn't break down at all. If you have one like that, try 1-2 light passes per side, always alternating if you do 2, at an angle much higher than what you sharpened at. At this point, check to see if you still see the burr, and if it's any sharper. If it is you can then back sharpen at your normal angle with 5 or so passes per side with the same stone, again making sure to alternate sides.


If it's still not as sharp / the 'burr' is still there, my guess is you don't have a burr and simply haven't apexed that portion as well as the rest of the blade, and simply need to spend a little more time there at an angle just slightly higher than you think.

_______________________________________________________________________________________________

Always in search of a good choppa'

ognennyy,
Try spot sharpening that area, just focusing on the belly, same thing with de-burring and stropping.

"I am still discussing issues of steels and performance at this stage."
--Cliff Stamp

"Cause geometry cuts, .....steel determines the level and the duration"
--Roman Landes

"But in general, I'm all about high performance, Ergos, safety. That's why I've been accused of 'designing in the dark' "
--Sal Glesser

Jason and Amber it would appear that I am your new knife sharpening student! Thank you for again offering advice. I will try that this evening after work.

Something else I thought of with regard to the burr... maybe I need to rethink how I approach sharpening and I can avoid the issue in most cases. It is my general understanding that the more I polish the apex and the portion right above the apex, the less friction there will be with a material as I cut through it. Therefore polishing the area above the apex contributes to how well your blade cuts.

Should I just skip trying to polish large portions of the blade, and instead focus only on sharpening the very apex of the blade with extremely light pressure strokes? What do you guys do? Do you polish large portions, or just sharpen the apex?

Obviously we're talking about knives without any significant damage or chipping to the apex. Situations where the apex is already properly shaped, and all I need to do is sharpen the apex.

I just do the edge bevel and apex...if the edge bevel is more than 1/8 wide, I need to think the blade I think.

_______________________________________________________________________________________________

Always in search of a good choppa'

Jason,
Amber,

Thank you for the advice. Amber through your suggestion I have discovered that it is, in fact, a burr that I always get on my belly line transition, no matter what grit stone I use, or which knife I sharpen.

With your advice along with Jason's on how to remedy a burr, I have been able to remove that burr. Hopefully with time I will correct my technique and learn to not let that annoying burr form at all.

Thanks

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C Amber
Do you have any diamond stones, or Spyderco ceramics? You want a hard stone that cuts well and doesn't break down at all.

I do not have any diamond stones or Spyderco ceramics at this time. But based on what you've said, and pending the advice of several members here, I'm considering not using my 5000 stone anymore. As you've previously identified it's a soft stone that breaks down fast. I think maybe it takes more experience than I have to use a soft, slow cutting stone.

Thanks

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ognennyy


With your advice along with Jason's on how to remedy a burr, I have been able to remove that burr. Hopefully with time I will correct my technique and learn to not let that annoying burr form at all.

Getting a decent finish on curved blades with large stones is a skill very few people have, hence why most people resort to rods. If you can do that you are in a fairly elite class.

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CliffStamp

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ognennyy


With your advice along with Jason's on how to remedy a burr, I have been able to remove that burr. Hopefully with time I will correct my technique and learn to not let that annoying burr form at all.

Getting a decent finish on curved blades with large stones is a skill very few people have, hence why most people resort to rods. If you can do that you are in a fairly elite class.

Thanks. Now I don't feel so bad about the fact that no matter how hard I try, or how much I take my time when I water stone sharpen, I still have to finish with some light stropping on white compound to get the sharpest edge that I can achieve. I think my next purchase will indeed be one of those above referenced spyderco ceramic rods and give them a try.

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ognennyy

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CliffStamp

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ognennyy


With your advice along with Jason's on how to remedy a burr, I have been able to remove that burr. Hopefully with time I will correct my technique and learn to not let that annoying burr form at all.

Getting a decent finish on curved blades with large stones is a skill very few people have, hence why most people resort to rods. If you can do that you are in a fairly elite class.

Thanks. Now I don't feel so bad about the fact that no matter how hard I try, or how much I take my time when I water stone sharpen, I still have to finish with some light stropping on white compound to get the sharpest edge that I can achieve. I think my next purchase will indeed be one of those above referenced spyderco ceramic rods and give them a try.

From what You have written already I think the sharpening potential
of all water stones You currently have is quite good..
the rest ( 90% ) is just a matter of understanding the process and skilled hands..

Actually, stone will have bigger contact area with the edge than rod has which means:

1) You can remove metal faster (on stone).
2) You can achieve thinner (sharper) edge (on stone) as can achieve
lower pressure (force to area) on the cutting edge.

(ofc there are exceptions for knives with unusual geometry,
or inoptimal combinations of abrasives relative to blade materials etc..)

Take a cheap knife with not crap blade steel perhaps easy to grind
f.e. plain carbon steel or sandvik or so... and sharpen them and try
to achieve maximum sharpness.. that way you learn and get more skill..

Your barks are not cheap and made of steels not so easy to sharpen
so learning takes long with them. Also for similar money
I would recommned to get knife from Andrey Biryukov.
I handled 2 knives made by him, they performed great
in Pavols tests and egronomics are excellent.
Honestly barks are nowhere near in cutting performance
and edge retention.

www.instagram.com/jscuttingtools

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JSCT
From what You have written already I think the sharpening potential
of all water stones You currently have is quite good..
the rest ( 90% ) is just a matter of understanding the process and skilled hands..

Actually, stone will have bigger contact area with the edge than rod has which means:

1) You can remove metal faster (on stone).
2) You can achieve thinner (sharper) edge (on stone) as can achieve
lower pressure (force to area) on the cutting edge.

It's really starting to sink in that I just need practice. When I watch vids of other people sharpening, it's very apparent that it takes time and skill. I never thought that sharpening could have such subtlety, beauty, and mastery.

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JSCT
Take a cheap knife with not crap blade steel perhaps easy to grind
f.e. plain carbon steel or sandvik or so... and sharpen them and try
to achieve maximum sharpness.. that way you learn and get more skill..

When you say plain carbon do you mean a steel that has no chromium, vanadium or molybdenum? Or just a higher than average presence of carbon in the steel?

Candidates I've found for a practice knife according to your suggestion:


I've had one of these for years [www.wusthof.com] It's a good knife, not cheap and not expensive. It's made of X50CrMoV15 steel (https://www.knivesandtools.com/en/ct/steel-types-for-kitchen-knives.htm) which contains .5% carbon, 15% chrome according to the article I linked. When I read through some steels I found at [www.knifecenter.com] .5% carbon seems actually a little low. There are other steels listed there that have as much as 1.5% carbon.

Of all the candidates I prefer this one. I already own one so that helps. But mostly it's a large blade, so I can practice and practice and practice and still have knife blade left after hours practicing on the stones.


[www.bladehq.com] is a Sandvik 12C27 blade (https://www.materials.sandvik/en/products/strip-steel/strip-products/knife-steel/sandvik-knife-steels/sandvik-12c27/) whose carbon content is .6% It's only a 4" blade however and costs $80. That's a little more than I was hoping to spend on a practice blade, and it's small so it won't last long as a practice device.



[www.bladehq.com] here's one with .8% carbon in the blade which is made from 8CR13MOV steel (http://skif-knives.com/en/publications/8cr13mov-en) Again a small blade, but has a higher amount of carbon in the steel, and it's only $60.



Do you recommend any of these? If not can you point me in the direction of a knife that meets your criteria for plain carbon steel?

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JSCT
Your barks are not cheap and made of steels not so easy to sharpen
so learning takes long with them. Also for similar money
I would recommned to get knife from Andrey Biryukov.
I handled 2 knives made by him, they performed great
in Pavols tests and egronomics are excellent.
Honestly barks are nowhere near in cutting performance
and edge retention.

I've been buying BRKT knives because they're pretty. But I'm starting to get the impression that they're not well respected for performance among the knife community, and that the owner is... less than reputable.

I searched the web for an hour after reading this and cannot find a single Andrey Biryukov knife for sale. I did find archives of knives already sold. For example on bladeforums.com in the for sale by individual section there were 8-10 listings, but all were already sold and for around $400 - $500. Maybe in a few seasons when I have more practice at sharpening and won't ruin the blade, I would be willing to spend $500 on a hunting knife. Especially if the's the last one I'll ever purchase.

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ognennyy
When you say plain carbon do you mean a steel that has no chromium, vanadium or molybdenum?
Or just a higher than average presence of carbon in the steel?

Plain carbon steel is something that only contains carbon and iron.
(Manganese and Silicon in little amounts as low as 0,5% or less
and impurities as S and P up to 0,03% usually - cleaner steels have less)

They are easy to grind despite very strong that is why I recommend it
as can take very keen and sharp edge more easily than complex steels..

If you dont have such knife I wouldnt spend so much for a knife just to practice..
Maybe train with paring knife it will be easy to grind steel - despite stainless..
find someting like this - Most likely have home something similar that would do just fine..

Your wusthof would be ok but I assume despite the steel would be easy to grind by most stones
they are usually thick behind the edge and the bevels arent very narrow meaning one must sharpen
more surface and it can take long time.. thick knife from easy to grind steel would take more time
to apex than high wear resistant steel kinfe ground very thin..

Your nick is in russian, I assume You are russian: Andrey Biryukov Honestly I think his knives are best performing blades in that price range..
They arent high end customs might have a little scratch here and there but are well made with
good fit and finish and they cut very well being made of material having always a perfect heat treat..

Bark rivers are nice knives having many good models but they got "famous" for powergrinding
knives without any coolant on high speed belts and basically overheating the steel..
and then quenching it into water.. after which they claimed its perfectly ok..

www.instagram.com/jscuttingtools

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JSCT
f you dont have such knife I wouldnt spend so much for a knife just to practice..
Maybe train with paring knife it will be easy to grind steel - despite stainless..
find someting like this - Most likely have home something similar that would do just fine..

Perfect. I have a Victorinox 8" boning knife. I remember that it is easy to sharpen. I'll practice with that.

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JSCT
Your wusthof would be ok but I assume despite the steel would be easy to grind by most stones
they are usually thick behind the edge and the bevels arent very narrow meaning one must sharpen
more surface and it can take long time.. thick knife from easy to grind steel would take more time
to apex than high wear resistant steel kinfe ground very thin..

It is very difficult for me to sharpen an edge with a thick bevel. I bought these broadheads for bow hunting this year, take a look.
[www.rmsgear.com] The bevel is very wide. When I try to sharpen the whole bevel, it does not remove metal evenly. I can see by looking at it that some parts of the bevel (toward the middle) have been worn more than the tip and the back end. I don't know if it's because they were not manufactured well but probably just my lack of experience causing the uneven wear. To sharpen them I had to make a small micro bevel on the very apex. I think I will stay away from wide bevels for now.

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JSCT
Your nick is in russian, I assume You are russian: Andrey Biryukov Honestly I think his knives are best performing blades in that price range..
They arent high end customs might have a little scratch here and there but are well made with
good fit and finish and they cut very well being made of material having always a perfect heat treat.

I almost married a Russian woman a long time ago so I learned the language. Thank you for the link. I'm looking forward to trying one of his knives, probably next hunting season.