Very poor edge retention when cutting cardboard

[Guy McVer]

Perhaps you need a brighter light, in a dimly lit room?

That's not an issue. I am checking in low light and my flashlight is bright enough that I have to be careful not to blind myself from the reflection if I accidentally hold it at the wrong angle.

Not to diminish the value of visually identifying a burr, but it's just that beyond a certain point, it can't be detected by sight anymore. There are just limitations to what you can see with this method. I'm personally finding that my own ability to detect a burr by touch is superior to seeing one with a flashlight. It may not be the same for everyone.

 

[elevator man]

Could you clarify this a little? I can't tell whether you are talking about a chip or a spot without a burr, or just a spot which hasn't apexed yet.

Keep in mind that there are other methods to identify irregular spots along the edge.



I can see how it could definitely be a great way to quickly train your ability to identify a burr by touch, at least up to the point when the light is no longer revealing a very tiny burr which is too small to cause a visible reflection.

I was sharpening the last 1/16" against the ricasso, so alot of steel to grind down. This raised the one side of the stone and I needed to go until the whole stone was touching, it was getting hard to tell when I'd finally got it done by feel, feeling for a missing tiny little bit of burr in the middle of where the stone was. It was quite helpful to see it

 

[elevator man]

As far as an indistinguishable burr that can't be seen or felt. I'm starting to think stropping is helpful in removing any remaining burr. But only on the right substrate that wraps around the apex to cut it off essentially. I'm using denim and have had no burrs I can tell since stropping on denim.

 

[TheOne45]

As far as an indistinguishable burr that can't be seen or felt. I'm starting to think stropping is helpful in removing any remaining burr. But only on the right substrate that wraps around the apex to cut it off essentially. I'm using denim and have had no burrs I can tell since stropping on denim.

Otherwise I agree but I had a problem with denim. I don't use hanging strops; only strops glued with double sided tape on a hard surface. I couldn't find the way to clean denim when it got clogged and glazed. I had to replace it. Leather strops I have I just clean with box cutter blade and sanding paper and apply new compound.
You also get ''wrap around apex'' effect with leather; it's combination of three factors: thickness and hardness of leather and applied force.
For example; on my guided system I use DIY strops made of very thin leather with short fibers glued on plexi glass. What do I do? I adjust stropping angle to get ''wrap around apex'' thing.

 

[TheOne45]

I'm personally finding that my own ability to detect a burr by touch is superior to seeing one with a flashlight.

I need to ask because I don't understand completely;
do you check for the bur with your fingers at the end of sharpening (before burr removal process) or you use this method after you removed the bur?

 

[Guy McVer]

do you check for the bur with your fingers at the end of sharpening (before burr removal process) or you use this method after you removed the bur?

I don't understand the point of the question. Yes to both. Why would you ever not check for a burr at either stage?

 

[elevator man]

I also

Otherwise I agree but I had a problem with denim. I don't use hanging strops; only strops glued with double sided tape on a hard surface. I couldn't find the way to clean denim when it got clogged and glazed. I had to replace it. Leather strops I have I just clean with box cutter blade and sanding paper and apply new compound.
You also get ''wrap around apex'' effect with leather; it's combination of three factors: thickness and hardness of leather and applied force.
For example; on my guided system I use DIY strops made of very thin leather with short fibers glued on plexi glass. What do I do? I adjust stropping angle to get ''wrap around apex'' thing.

I also use denim stapled to mdf. I think it's just the nature of what I'm doing, I'll just replace the piece of denim when it's no longer effective. One old pair of work pants will make lots of strops

 

[TheOne45]

I don't understand the point of the question. Yes to both. Why would you ever not check for a burr at either stage?

If there are some remains of a burr after I strop the blade they are so small there is no way I could feel them with my fingers.
I can barely see those pieces with my 60x loupe.
I somehow doubt someone can have so sensitive fingers to detect so small particles.

 

[TheOne45]

I also use denim stapled to mdf. I think it's just the nature of what I'm doing, I'll just replace the piece of denim when it's no longer effective. One old pair of work pants will make lots of strops

I got tired removing the tape and replacing the denim. Leather also works good for me.

 

[Blade Lab]

I can definitely feel a burr that doesn't show up with the flashlight trick. The flashlight is also not that effective when sharpening with coarse grit, because the deep scratches themselves reflect.

 

[Guy McVer]

If there are some remains of a burr after I strop the blade they are so small there is no way I could feel them with my fingers.
I can barely see those pieces with my 60x loupe.
I somehow doubt someone can have so sensitive fingers to detect so small particles.

I don't use magnification, so I wouldn't know. It simply stops mattering to me when it gets to the point that I can't feel a burr anymore.

If I feel a burr, then it's there regardless of whether I can see it or not.

When I can't feel a burr, then I don't worry about how to define what is and isn't technically a burr. I just use my knife.

 

[JTR357]

I don’t do any science and angle stuff but you can forget all the edge retention princess stuff with cardboard. I use AUS 8A and it works fine for week or two in active use depending on how sharp I want the edge to be or how lazy I am to sharpen. Then you just sharpen quickly in about five minutes and get something else to do.

I dulled my Spyderco Delica with Cruwear pretty badly just breaking down 3 boxes. Cardboard eats up edges.

 

[Zenturio]

I am very happy that so many of you take part in that discussion. It is so nice that various experiences can be compared.

Personally, I never wanted to strop because I thought a microbevel would be the better choice for strenghten the very apex and deburring.

After the start of that topic I tried to change my system. I sharpened my S30V DLC Shaman a few days before with a guided system (KMFS), 18dps.
I used 240# diamond, 600# diamond, made a few deburring passes on a fine Spyderco ceramic rod (after that, there was still a burr, because shaving my armhair in both directions would not work).
Then I did 15-20 passes on a kangaroo leather strop (Jende), loaded with 1,5 micron CBN emulsion (KME).
I think that the burr was fully removed. Shaving hair in both directions was not a problem. Splitting hair with a little relative movement along the edge also worked.

Then for verification I did 20 cuts into hard wood, also twisted the edge and checked for micro ships, but the edge still was perfect with certain amount of bite.

So far I am very happy with those results. I ordered a better loupe and will try to send you some pictures of the edge.

I now think that deburring passes on ceramic and a little stropping on a suitable media is the way to go for burr removal.

The goal, at least for me is, that in the end I get a deburred edge with quite amount of bite left.

Looking forward to hearing from you.

BR Oliver

 

[TheOne45]

Then for verification I did 20 cuts into hard wood, also twisted the edge and checked for micro ships, but the edge still was perfect with certain amount of bite.

It's all in the strop man..... all in the strop.
By the way, I don't use ceramic rods but I do use the same wood method to check the edge.

 

[Guy McVer]

So I got this cheap chineseum knife recently. The edge was garbage on it. It would raise a big nasty burr way too easily when I would got to sharpen it. After several sharpenings, this problem basically went away once I got down to some better steel (the heat treat must have been ruined along the edge during the grinding process). It still has this one problem spot, but I think over time, that should go away just like it did with the rest of the edge.

Point is, it's a soft, garbage knife. But as it turns out, even a cheap soft garbage mass produced chinese knife can do just fine with cardboard.

I just used it to completely break down several cardboard boxes, and it held up just fine. Is it covered in dookie and scratched to hell now? Yup. Will it shave after cutting so much cardboard? Nope. But I think that would be expecting way too much after all the cardboard slicing that it did. Even for a supersteel it would be unreasonable to expect to be able to shave with it after all that.

I keep coming back to this point in my head: "does the knife do the job that I want it to do?" If yes, then be happy. It really is okay for a knife not to have a microscopically perfect edge all the time. It will still cut.

 

[garry3]

Ease of touch up > super steel?

 

[Guy McVer]

Ease of touch up > super steel?

That would be my own personal preference, yes. Easier on the wallet, easier on the stone. But I recognize that other people may have their own preferences and they may have good reasons for preferring supersteels.

 

[Drop bear]

I saw a video on this about a complaint on factory edges.
And the angle is too obtuse I think and flattens out too easily. And limits the edge retention on cutting tests.

Possibly mentioned here. I have the sound off.

 

[garry3]

That would be my own personal preference, yes. Easier on the wallet, easier on the stone. But I recognize that other people may have their own preferences and they may have good reasons for preferring supersteels.

I see it in the field with hunting knives too. Several factors are involved though.

 

[Guy McVer]

I saw a video on this about a complaint on factory edges.
And the angle is too obtuse I think and flattens out too easily. And limits the edge retention on cutting tests.

Possibly mentioned here. I have the sound off.

I don't think he talked about that, but he does discuss how the steel is "fatigued" from the factory grind, and that it takes several sharpenings to get to the good steel underneath the area which was ruined at the factory. Basically it's the same thing as I mentioned earlier: the factory grinding process can ruin the heat treat at the edge, and you need to remove the ruined steel by sharpening the knife until it's all gone.

I feel like I should get a medal for watching that whole video...