Getting blade chipping while sharpening 154CM

[HeavyHanded]

Well this appears to have been the issue. I scrubbed the coarse stone with a wire brush and then did a full resharpen of an AUS-8 blade, and had no issues. I left everything the same with the mini-grip as it was before (angle, clamp position, etc.) and so far I am not having the same issue. I am slowly building up the edge and it is uniformly smooth across the entire blade. It will take a while (this 154CM is hard stuff!), but I'll post a picture of the finished edge when I am done.

Lesson for me today? Invest in a proper stone flattening device rather than using the concrete method. Thanks for all the assistance everyone!
Dave

Once that stone's flat and broken in, it should stay pretty much flat for many years. I highly recommend using oil with it, will float a lot of the removed steel and any abrasive that gets knocked loose, keeps the surface in great shape and grinding as cleanly as possible.

 

[SunOfAtom]

I obviously spoke too soon :grumpy:

I had what appeared to be a very fine burr built up, which I was slowly trying to remove by lightly going across the coarse stone, spine first, a couple of times each side and then flipping sides and repeating. I could see pieces starting to come off, though they looked much larger than the burr itself. Hoping I was mistaken, I moved to the fine India stone and did a handful of passes on each side. Unfortunately, I am right back to where I was before. In an approximately 1" section at the heel end of the blade, I had a bunch of the edge break away.


The pictures are going from the heel towards the tip, with the last picture giving an overall view where I marked the problematic area.

Well, I am at a loss. Am I somehow overworking the blade? I am using really light pressure and taking my time. The stone is not as rough as it was when it was new, so it definitely takes a while. I have a new coarse crystolon stone coming this weekend, so that will give me something new to try. Is the angle too acute for this sharpening process? Unless we can come up with a different possibility, I think my next test will be to up the angle a bit and try again.

 

[SunOfAtom]

Once that stone's flat and broken in, it should stay pretty much flat for many years. I highly recommend using oil with it, will float a lot of the removed steel and any abrasive that gets knocked loose, keeps the surface in great shape and grinding as cleanly as possible.

I always use plenty of sharpening stone oil, and remove/replace with clean oil when I can see it is getting a buildup of metal. The picture I posted was just showing my blade position, and since I was not using that stone at that time, it did not have any oil on it.

I was not sure how frequently I needed to flatten the stone, but I figured it could not hurt. It mainly felt gummed up and had lost its "bite." I guess the loss of bite is just the natural progression of the stone and what I should expect. The gummed up feeling was coming from the fact that I had just experimented using a thin coat of vaseline to prevent the coarse stone form soaking up so much sharpening oil. It was probably just fine, but after just using oil, it felt too smooth.

 

[Obsessed with Edges]

The thing that continues to bug me, in looking at the pics (most apparent in the first two pics), is what still appears to be a hair-thin reflection of light along the edge, suggesting a long burr/wire edge or rolled edge. Not just where the deepest 'dents' are, but continuous. I'm using my browser to zoom in on the pics, and that little continuous glint of light steadily remains, through the length of the damaged-looking section. With chipping, I'd more expect to see sections of the edge crisply-apexed and sharp (looking more like the belly area of your edge, which looks good and crisp), intermittently interrupted by the gaps creating by steel chipping out.

Can you feel any steel folded to one side or the other, with your fingernail/thumbnail? Or does any of this steel come off, if lightly drawing the edge across the edge of your thumbnail? I'm trying to get some sense of how fragile these broken remnants are, which is why I ask. In the past, on some very softish blades (inexpensive kitchen stainless), I've created some large and very thin burrs that tended to break away in large pieces like you describe, even leaving little bits of it on my fingertips when feeling the edge.

David

 

[HeavyHanded]

Those pics are very well done. I'd consider an email and phone call to BM. The images clearly show no deep gouges etc running to the shoulder that would indicate the issue was coming from the stone or excessive pressure. The blade has no warps, and is clean on either side of the problem area. 30* is not too acute for that steel.

I gave my India stones an initial lapping with 220 grit silicon carbide grit and soapy water. It made the surface more uniform, but really wasn't needed except that it softened the side edges a bit - they were crisp to the point of being troublesome when it came out of the box. That's what prompted my first suggestion about riding the outside edge.

I just sharpened a co workers Griptilian in 154cm and it took less than 15 minutes, including the narrative (he and a buddy are considering buying a couple of Washboards so he got the 25 cent tutorial) - had never been sharpened since it left the factory and had been used hard for about a year - serrations all showed burring on the inside curves and the edge had a few chips and more hard-use burring. Steel behaved beautifully. I normally don't entertain issues with the HT on a production knife and cannot imagine how it could be pooched in one spot like that, but am at a loss to explain your troubles...

Martin

 

[BluntCut MetalWorks]

Oh my blurry eyes ... look like you need to take away some more metal before the edge is free from factory over-grinded edge (or you dug one earlier).



Try again but first grind the apex away - with blade almost vertical (edge to spine) - until dip/recurve gone. And make sure the hole gone when re-establish the bevel, i.e. same scratch pattern/depth heel to tip on both side.

 

[SunOfAtom]

The thing that continues to bug me, in looking at the pics (most apparent in the first two pics), is what still appears to be a hair-thin reflection of light along the edge, suggesting a long burr/wire edge or rolled edge. Not just where the deepest 'dents' are, but continuous. I'm using my browser to zoom in on the pics, and that little continuous glint of light steadily remains, through the length of the damaged-looking section. With chipping, I'd more expect to see sections of the edge crisply-apexed and sharp (looking more like the belly area of your edge, which looks good and crisp), intermittently interrupted by the gaps creating by steel chipping out.

I am wondering if what you are seeing is me trying to get the light to reflect in such a way that I can get the camera to focus. Here are a couple of full size pictures where I angled the blade so that the light was shining down on top of the broken edge. I'll see if I can get some better ones once my camera battery recharges.

Image 1
Image 2

Can you feel any steel folded to one side or the other, with your fingernail/thumbnail? Or does any of this steel come off, if lightly drawing the edge across the edge of your thumbnail? I'm trying to get some sense of how fragile these broken remnants are, which is why I ask. In the past, on some very softish blades (inexpensive kitchen stainless), I've created some large and very thin burrs that tended to break away in large pieces like you describe, even leaving little bits of it on my fingertips when feeling the edge.

David

The edge of the knife looked great up until I went to remove the burr. The burr was maybe the thickness of a hair, just enough to catch the light or to easily feel when sliding my finger across it. The burr was also pretty consistent across the entire blade. When I started to do light spine-first strokes to remove the burr, I could see large pieces breaking off. At that point I did brush my thumb across the edge of the blade (not along it) and more pieces came off. That is when I moved to the fine stone to confirm my fears of what I was seeing. The burr came off normally, leaving a nice sharp edge everywhere except in that 1" section where larger pieces of the blade flaked off. So strange.

 

[Obsessed with Edges]

Oh my blurry eyes ... look like you need to take away some more metal before the edge is free from factory over-grinded edge (or you dug one earlier).

View attachment 428571

Try again but first grind the apex away - with blade almost vertical (edge to spine) - until dip/recurve gone. And make sure the hole gone when re-establish the bevel, i.e. same scratch pattern/depth heel to tip on both side.

Think this is on the right track. I'm somewhat bugged at how 'soft' this edge seems to look, and the factory-damaged steel prospect is still what's looking most likely to me. If it doesn't grind off pretty soon, I might be inclined to send the knife back to BM and let them figure it out (or replace it). I hate to suggest that, ordinarily, because it's often a scapegoat to blame for other true causes; but this one doesn't seem right to me.


David

 

[Obsessed with Edges]

I am wondering if what you are seeing is me trying to get the light to reflect in such a way that I can get the camera to focus. Here are a couple of full size pictures where I angled the blade so that the light was shining down on top of the broken edge. I'll see if I can get some better ones once my camera battery recharges.

Image 1
Image 2




The edge of the knife looked great up until I went to remove the burr. The burr was maybe the thickness of a hair, just enough to catch the light or to easily feel when sliding my finger across it. The burr was also pretty consistent across the entire blade. When I started to do light spine-first strokes to remove the burr, I could see large pieces breaking off. At that point I did brush my thumb across the edge of the blade (not along it) and more pieces came off. That is when I moved to the fine stone to confirm my fears of what I was seeing. The burr came off normally, leaving a nice sharp edge everywhere except in that 1" section where larger pieces of the blade flaked off. So strange.

That's almost exactly what I was seeing in that very soft kitchen stainless blade I mentioned before. The steel would burr very easily, and the burrs would widen to ridiculous extremes if continuing to grind away, leaving the extremely thin remnants clinging onto the edge until I rubbed them off. For a cheap stainless kitchen blade, no big surprise. But, for BM's 154CM, it's not right at all. Seems much too soft.


David

 

[SunOfAtom]

Oh my blurry eyes ... look like you need to take away some more metal before the edge is free from factory over-grinded edge (or you dug one earlier).

View attachment 428571

Try again but first grind the apex away - with blade almost vertical (edge to spine) - until dip/recurve gone. And make sure the hole gone when re-establish the bevel, i.e. same scratch pattern/depth heel to tip on both side.

Looking at the knife from the side, there is definitely a slight dip in this section of the blade. Do I want to focus more on removing the excess blade at the back end of the blade (by the handle), or do I grind evenly on both sides of the dip until the area is flat? Maybe there is no real difference, I am just hoping to avoid doing any more unnecessary damage to this poor blade, and don't want to end up making an oddly shaped blade. I am still having a hard time fully understanding the affects a recurve has on sharpening on a flat stone (as well as how to remove an unintended one), so if anyone has any words of wisdom or links to tutorials, that would be greatly appreciated!

What is it about this dip that is causing this issue? The AUS-8 knife (SOG Twitch II) that I just had success sharpening does have a slight recurve in that same area, but that one sharpened nicely (though the recurve is still present). Thanks for the input, this definitely seems to be a factor here.

 

[Squashfan]

That's almost exactly what I was seeing in that very soft kitchen stainless blade I mentioned before. The steel would burr very easily, and the burrs would widen to ridiculous extremes if continuing to grind away, leaving the extremely thin remnants clinging onto the edge until I rubbed them off. For a cheap stainless kitchen blade, no big surprise. But, for BM's 154CM, it's not right at all. Seems much too soft.


David

I had that happen to me on a Kershaw Crown. The burr came off in big flakes. That was back when I was using the Lansky so I don't remeber what stone I was using.

 

[BluntCut MetalWorks]

Minigrip blade doesn't has recurve.

put the apex flat on stone surface (hence high points heel + otherside of dip), grind until no more light gap shown through. Ignore the hole on the bevel, that area edge bevel will be smaller/short/(sort-of micro) but will even out after a few sharpening.

 

[HeavyHanded]

Looking at the knife from the side, there is definitely a slight dip in this section of the blade. Do I want to focus more on removing the excess blade at the back end of the blade (by the handle), or do I grind evenly on both sides of the dip until the area is flat? Maybe there is no real difference, I am just hoping to avoid doing any more unnecessary damage to this poor blade, and don't want to end up making an oddly shaped blade. I am still having a hard time fully understanding the affects a recurve has on sharpening on a flat stone (as well as how to remove an unintended one), so if anyone has any words of wisdom or links to tutorials, that would be greatly appreciated!

What is it about this dip that is causing this issue? The AUS-8 knife (SOG Twitch II) that I just had success sharpening does have a slight recurve in that same area, but that one sharpened nicely (though the recurve is still present). Thanks for the input, this definitely seems to be a factor here.

If the recurve wasn't there to begin with, it means the handle is being dropped slightly as this region is being worked, and making contact with the rough edge of the stone - the opposite movement of raising the handle to hit the belly, but much more subtle. This is what I was getting at earlier.

If it came with a recurve it means the blade made poor contact or was stalled on a powered surface (grit wheel from a paper wheel set-up or a hard platen backed belt sander) and might have effected the HT right there. Having the recurve will also prevent the edge from making good contact with a nice flat stone like your India when being resharpened and will cause issues with putting on a nice edge.
The only time I've had an issue like the one you're experiencing was when I put a sub 20* single bevel on a Mora classic using 120 grit - edge had zero lateral stability and broke up like overheated aluminum foil when pressed with the side of a pen.

 

[Sam Wilson]

I am not a sharpening guru by any means, but I'll offer my opinion. Based on your initial post of spending hours on this blade, it looks to me like you've got a really wide burr, which would behave exactly like you're experiencing. The burr is a very thin, weak flake of metal on the edge, basically, and as it breaks off, it doesn't always do so uniformly. It often looks exactly like your pictures. Once you get it down, it should take only a few minutes to sharpen the edge with stones. I know you mentioned reprofiling, but even so, the number of hours you spent is way in excess of what it would take to do it. You have probably ground a very thin burr, and until it's gone, it will continue to "chip" out on you.

As for 30 degrees being too much, keep in mind that is just the angle of the edge. That does nothing to take into account the thickness of the edge before it's sharpened. If the edge is finished thick from the factory, even a 15-20 degree-per-side angle is going to leave plenty of metal on there for normal use. The converse is also true. If the edge is ground thin, a more obtuse angle will maintain the strength and integrity of the edge. Most factory knives are left plenty thick at the edge. Hope some of that is helpful.

Sam :thumbup:

 

[Jason B.]

This looks very much like the result you get for sharpening/honing a steel with high hardness on a hard stone. When a blade is at a higher hardness and a honing steel or hard stone like a ceramic is used the amount of deflection becomes so high it chips the edge.

The Norton India is a harder stone but not nearly as hard/dense as ceramic or a honing rod. The steel on that knife shouldn't be that hard either, you need to be in the low to mid 60's HRC in most cases to see this type of damage. The silicon carbide stone if softer so if that corrects the issue then you probably have a blade that is extra hard. If not then you might have a defective blade, this is highly unlikely but possible.

Does the edge feel different in that section as compared to the belly/tip? A soft or gummy feeling?

 

[SunOfAtom]

This is the first time I have sharpened this knife, so unless I am missing something, any unintentional recurve was there from the factory. I never move the knife down the stone with the heel of the blade hanging off the end of the stone, which is why I don't think I created it. This knife (as with most of my knives) has never seen hard use, so the factory edge was still really nice when I started. I was only attempting to resharpen it to gain some practice/experience. I really like the look and feel of the more acute angles on my Spyderco knives, which is why I went with a decreased angle from what it had originally.

With the exception of the roughness, I do not feel anything different about the problematic area of the blade versus the rest of it. I guess my next step will be to grind down the back 2/3 of the blade to remove the chipping as well as the recurve. Given how little the coarse stone seems to bite into this particular steel, I would guess that it will take a few hours to cut the new bevel back into it. Could I be using too little pressure? It sure does not seem like more pressure would be beneficial. Given how long it takes and how many times I have been through this already, I should probably wait for my new coarse stone to arrive, but I don't really want to wait that long for some resolution.

Currently I see my options as:
1. Grind down the back of the blade on the mini-grip and sharpen again using the same exact process.
2. Same as above, but increase the bevel (40° inclusive?)
3. Wait until the Crystolon stone comes in, use that to grind down/resharpen.
4. Drag another innocent knife into this mess by trying the same resharpening on another Benchmade 154CM (Torrent 890)
5. ?

Ugh.
Dave

 

[78LilRed]

Get rid of the recurve before doing anything drastic to ensure full contact to the stone.

 

[Obsessed with Edges]

This is the first time I have sharpened this knife, so unless I am missing something, any unintentional recurve was there from the factory. I never move the knife down the stone with the heel of the blade hanging off the end of the stone, which is why I don't think I created it. This knife (as with most of my knives) has never seen hard use, so the factory edge was still really nice when I started. I was only attempting to resharpen it to gain some practice/experience. I really like the look and feel of the more acute angles on my Spyderco knives, which is why I went with a decreased angle from what it had originally.

With the exception of the roughness, I do not feel anything different about the problematic area of the blade versus the rest of it. I guess my next step will be to grind down the back 2/3 of the blade to remove the chipping as well as the recurve. Given how little the coarse stone seems to bite into this particular steel, I would guess that it will take a few hours to cut the new bevel back into it. Could I be using too little pressure? It sure does not seem like more pressure would be beneficial. Given how long it takes and how many times I have been through this already, I should probably wait for my new coarse stone to arrive, but I don't really want to wait that long for some resolution.

Currently I see my options as:
1. Grind down the back of the blade on the mini-grip and sharpen again using the same exact process.
2. Same as above, but increase the bevel (40° inclusive?)
3. Wait until the Crystolon stone comes in, use that to grind down/resharpen.
4. Drag another innocent knife into this mess by trying the same resharpening on another Benchmade 154CM (Torrent 890)
5. ?

Ugh.
Dave

Those last two options would (should) definitively eliminate either the stone (your India) or the particular blade as a problem. Given the circumstances, I think that's the path I'd take. The Crystolon is supposed to be better-suited to jobs like re-bevelling, and should make quick work of removing (potentially) problem steel from the edge, if it's there. And trying another blade of the same steel on your India stone should reveal whether the stone might be contributing to the problem or not. Might do that while you're waiting for the Crystolon to come in, and just set this knife aside until it does.

I don't think increasing the bevel angle to 40° would help or prove anything; if the steel's bad, it'll still be bad at 40°. 154CM, properly heat-treated and not otherwise compromised, should easily hold up at 30° anyway.


David

 

[SunOfAtom]

My guess right now is that there is some issue with this coarse stone (or stone/steel combo). I ground the heel down using near perpendicular passes until I had removed the recurve, then decided to give it another try. After a good 2 hours, I still had not yet brought back a sharp edge to the heel section and was starting to get small chipping along the belly. My guess is that given the time I have to spend on this stone, the thin sections of the blade are somehow getting overworked and end up getting brittle. The blade gets a surprisingly shiny finish while on this coarse stone and then just does not seem to cut. When I thought the blade was close enough, I switched to the fine India stone, lightly removed the chipped section on the belly, then continued with the entire blade. At some point I decided to see how it would be going back to the coarse stone. I ran the blade across it 5 or 6 times and took a look, and could not see any new coarse marks on it. That tells me that there is something up with the coarse stone.

At this point I think I will wait until the Crystolon stone arrives and then start fresh with this knife. If I could set a nice even coarse scratch pattern in a reasonable time and move on to the next stone, I think it would be fine.

Dave

 

[Bugout Bill]

If the edge isn't forming cleanly (let alone chipping out while sharpening), there is something wrong with the steel. Have you considered contacting Benchmade about it.