Ever get a burr before reaching the edge?

[rockscreation16]

I've been sharpening with my Lansky kit for years and was always satisfied with the results, and for all intents and purposes my knives are probably more than sharp enough. Lately, especially with my nicer knives I've been trying to achieve the sharpest edge I can possibly achieve. It's for no other purpose than to impress.

My most recent blade clamped into my sharpening system is the Benchmade 710 in M390. Might I say that's some hard steel? I've profiled the edge to a 20 degree angle, which I've heard is more like 18 degrees on the Lansky system. Every time I sharpen I achieve a burr and slowly work my strokes down through the stones to a ultrafine white stone. This polishes the edge to a mirror finish. I still am not totally satisfied with the level of sharpness i'm achieving. It seems like I'm never zeroing the edge completely. Like even though I'm achieving a burr multiple times I never reached the edge completely.

Anyone ever have this problem?

 

[KennyB]

Are you leaving the knife in the clamps in the same location through the entire processs?

That is mostly inconsequencial though... If you get a burr, you have brought each edge together at the apex.

I think if you are finding that this still isn't sharp there is something else at work. I'm betting that the burr is still on the edge, especially since you are working with M390 and it is very abrasion resistant.

 

[Obsessed with Edges]

Lots of things might be happening here.

Different steels can feel markedly different when 'sharp'. Some will feel more toothy and have more 'bite' at a given fine grit than others.

At the given angle mentioned (~18-20 degrees per side), the perceived sharpness may not meet expectations anyway, depending upon what you're doing to 'test' sharpness. And with the Lansky clamp in particular (or Gatco, DMT Aligner, etc.), there's no guarantee the angle's even in that ballpark, without actually measuring it. Most of the angle setting's accuracy is entirely dependant on the size/width of the blade, and it's positioning in the clamp. The 'indicated' angle setting on the clamp may not be even close to what you assume.

Aside from that, it's possible to go a little too far with the finer hones, in removing the burr formed on the first hone. The trick is to remove the burr only, and no more. When the burr forms initially, that's a pretty reliable indicator that the edge is fully apexed. From that point forward, it's important to go very, very gently in cleaning up the burr with the med/fine/UF hones, so the 'sharp' edge behind the burr doesn't get scrubbed away. When the edge is that fine, the tiny bit of angle variability in the Lansky's guided setup is enough to slightly blunt or round off the edge just a little bit. Going very slow & controlled, at very light pressure, is the best way to minimize any variability in the angle. Going too fast can make the hones bounce or skip on the edge, which can blunt it. Leaning too heavily into the hones can (and usually will) generate some bend/flex in the hone's guide rod, which creates variability in the angle. If the clamp's hold on the blade isn't completely tight & firm, the blade can rotate/pivot away from the pressure applied by the hone, which will add more variability. On thinner blades, the blade itself can flex enough to change the angle momentarily.

The possibilities mentioned in the last paragraph above are what I've run into the most, and I suspect are what you're likely seeing. As mentioned, the key is to watch for the burr, and then radically alter your approach to finishing, with strong emphasis on slow, controlled strokes and very light pressure. Keep a very close eye on sharpness as you go. When you can see you're getting very close, take only 2 or 3 passes at a time, and keep checking for improvement in sharpness. If you reach a plateau, when nothing seems to be changing significantly, that's the time to stop and make sure everything's under control, before moving on.

 

[rockscreation16]

Lots of things might be happening here.

Different steels can feel markedly different when 'sharp'. Some will feel more toothy and have more 'bite' at a given fine grit than others.

At the given angle mentioned (~18-20 degrees per side), the perceived sharpness may not meet expectations anyway, depending upon what you're doing to 'test' sharpness. And with the Lansky clamp in particular (or Gatco, DMT Aligner, etc.), there's no guarantee the angle's even in that ballpark, without actually measuring it. Most of the angle setting's accuracy is entirely dependant on the size/width of the blade, and it's positioning in the clamp. The 'indicated' angle setting on the clamp may not be even close to what you assume.

Aside from that, it's possible to go a little too far with the finer hones, in removing the burr formed on the first hone. The trick is to remove the burr only, and no more. When the burr forms initially, that's a pretty reliable indicator that the edge is fully apexed. From that point forward, it's important to go very, very gently in cleaning up the burr with the med/fine/UF hones, so the 'sharp' edge behind the burr doesn't get scrubbed away. When the edge is that fine, the tiny bit of angle variability in the Lansky's guided setup is enough to slightly blunt or round off the edge just a little bit. Going very slow & controlled, at very light pressure, is the best way to minimize any variability in the angle. Going too fast can make the hones bounce or skip on the edge, which can blunt it. Leaning too heavily into the hones can (and usually will) generate some bend/flex in the hone's guide rod, which creates variability in the angle. If the clamp's hold on the blade isn't completely tight & firm, the blade can rotate/pivot away from the pressure applied by the hone, which will add more variability. On thinner blades, the blade itself can flex enough to change the angle momentarily.

The possibilities mentioned in the last paragraph above are what I've run into the most, and I suspect are what you're likely seeing. As mentioned, the key is to watch for the burr, and then radically alter your approach to finishing, with strong emphasis on slow, controlled strokes and very light pressure. Keep a very close eye on sharpness as you go. When you can see you're getting very close, take only 2 or 3 passes at a time, and keep checking for improvement in sharpness. If you reach a plateau, when nothing seems to be changing significantly, that's the time to stop and make sure everything's under control, before moving on.

Sounds like a very good approach to correct the mistakes i've been making. I'll definitely try your suggestions through my next sharpening process.

The blade seems to be very secure in the clamp. I generally apply a couple of layers of masking tape to lock it in tight. When adjusting the clamp I try to make both sides of the clamp parallel.

I also make sure that the stone and guide are at the same position every time. I do this by laying the stone with rod face down on a flat surface and making sure it's level all the way across. Also making sure that the rod is locked at the same position.

I think that my main issue has to be how I'm working the burr off. Probably working the edge too much after creating the burr and eventually dulling it.

Would you create a burr back and forth through the stones until honing the edge with the ultra fine? Or are you saying that I should be gentle enough with the medium, fine, and ultra fine stones to never create another burr? Also, I've considered using a strop block after the stones. Would you recommend this?

Thanks for all of your help and your very detailed reply previously!

 

[Obsessed with Edges]

Sounds like a very good approach to correct the mistakes i've been making. I'll definitely try your suggestions through my next sharpening process.

The blade seems to be very secure in the clamp. I generally apply a couple of layers of masking tape to lock it in tight. When adjusting the clamp I try to make both sides of the clamp parallel.

IF the sides of the blade are parallel, that's fine. If the blade is a full flat grind (tapering/narrowing all the way to the edge), keeping the sides of the clamp parallel to each other may not hold the blade very securely. I've always made more effort to make sure the inside faces of the clamp are fully flush to sides of the blade. With a FFG (full flat grind), that means the two halves of the clamp will not be parallel, but will follow the taper of the blade's grind. Doing it this way keeps more of the clamp's gripping surface in full contact with the blade, which helps to keep the blade from moving in the clamp (either slipping, or pivoting away from the hone's pressure).

I also make sure that the stone and guide are at the same position every time. I do this by laying the stone with rod face down on a flat surface and making sure it's level all the way across. Also making sure that the rod is locked at the same position.

:thumbup: This is good. It's how I do it also.

I think that my main issue has to be how I'm working the burr off. Probably working the edge too much after creating the burr and eventually dulling it.

Would you create a burr back and forth through the stones until honing the edge with the ultra fine? Or are you saying that I should be gentle enough with the medium, fine, and ultra fine stones to never create another burr? Also, I've considered using a strop block after the stones. Would you recommend this?

Thanks for all of your help and your very detailed reply previously!

The burr should only be created once, with the coarse (first) hone. The remaining hones should be used to gently file it away, and then refine the scratch pattern on the bevels. No need to create a burr more than once. The purpose of creating a burr is to guarantee that you've fully apexed the new edge, which only needs to be done at the first stage. Once you've proven the existence of the burr on your edge, creating another/more burrs just removes a lot more steel than necessary, and creates a lot more work for you, to remove it each time. Also increases the likelihood of making mistakes as you go.

I'd heartily recommend trying a strop (block or hanging; your preference). So long as you've done the job fully with the hones (fully apexed edge), stropping afterwards is always a great way to help clean up any remaining burrs, and should also enhance sharpness (assuming good technique, of course).

 

[rockscreation16]

I've just established an edge on my new-ish grip 556 with 154cm. Much easier than the m390 of course, but I spent a good deal of time making precise strokes while honing. I used the 17 degree guide and made a zero grind edge. I worked it with the course stone until establishing a full burr on the opposite side. I tried to work gently after this, but I did end up making a burr a couple more times. I couldn't manage to get rid of the micro serrations. It was like I stood the burr up rather than honing it off. Don't get me wrong.. It's likely the sharpest I've gotten a knife thus far. It shaves like my triple blade safety razor and push cuts paper with ease. I'm sure the edge won't last long though. I just got my knives plus strop block in. It definitely helped the edge noticeably, but I can still see the micro serrations when I look closely. It's plenty sharp. I just want the edge to last as this application is for an EDC. Any ideas?

 

[Obsessed with Edges]

I've just established an edge on my new-ish grip 556 with 154cm. Much easier than the m390 of course, but I spent a good deal of time making precise strokes while honing. I used the 17 degree guide and made a zero grind edge. I worked it with the course stone until establishing a full burr on the opposite side. I tried to work gently after this, but I did end up making a burr a couple more times. I couldn't manage to get rid of the micro serrations. It was like I stood the burr up rather than honing it off. Don't get me wrong.. It's likely the sharpest I've gotten a knife thus far. It shaves like my triple blade safety razor and push cuts paper with ease. I'm sure the edge won't last long though. I just got my knives plus strop block in. It definitely helped the edge noticeably, but I can still see the micro serrations when I look closely. It's plenty sharp. I just want the edge to last as this application is for an EDC. Any ideas?

Sounds like you're doing OK. You've got the burr. All that's needed is to finish cleaning it up. Most of that can be done with the finest hone, using very gentle pressure (if you think your pressure is light, go even lighter). The idea is to keep thinning the burr with the finest hone, until it becomes thin enough to break away. If you have to flip the blade over a few times and work on both sides, so be it. So long as you keep it light & controlled, you should be fine. Seeing some micro-serrations in the edge isn't necessarily a problem. Test the edge by making slicing cuts into paper, cardboard, even wood. If a burr is still there, most of it should get scrubbed off by cutting into wood a few times. Hardwood is even better (I often use the edge of my oak strop block for this).