Dumb question about burrs.

[Squashfan]

I have all three of the Spyderco ceramic benchstones but what got me thinking was when I was sharpening a stainless machete with the Doublestuff pocket stone. I put on a microbevel with the medium side then switched to the fine. Very little, if any burr. IIRC, I finished the edge with a pass over my jeans and the machete was good to go. Then it occurred to me: If I can, by light pressure, cut the burr off on a machete why couldn't I do the same on a knife?

Is it possible to refine the burr so much that the edge wouldn't need stropped on a loaded strop? Maybe it is a crazy idea but I had noticed that the flexcut gold I have been using was turning out a large burr on a old camillus electrician knife that was sharpened on the Spyderco medium stone. A burr that was larger than the burr from the medium stone. Maybe if I took the edge all the way to the fine or ultra fine stone I could finish with just a plain copy paper (no compound) strop. Then again, I may just need to put my 1 and 3 micron DMT diapaste into action. I want to know what you guys think.

Thanks,
Charles

 

[Magnaminous_G]

Define "need." It's possible to get a perfectly good, almost burr-free edge without stropping, especially with finer stones. You can get a great, working edge coming off a coarse stone if your apexing and burr-removal technique is up to snuff. But you get to another level with just a little bit of stropping. Do you "need" to do it? Depends on you and what you want from your edge.

 

[HeavyHanded]

I have all three of the Spyderco ceramic benchstones but what got me thinking was when I was sharpening a stainless machete with the Doublestuff pocket stone. I put on a microbevel with the medium side then switched to the fine. Very little, if any burr. IIRC, I finished the edge with a pass over my jeans and the machete was good to go. Then it occurred to me: If I can, by light pressure, cut the burr off on a machete why couldn't I do the same on a knife?

Is it possible to refine the burr so much that the edge wouldn't need stropped on a loaded strop? Maybe it is a crazy idea but I had noticed that the flexcut gold I have been using was turning out a large burr on a old camillus electrician knife that was sharpened on the Spyderco medium stone. A burr that was larger than the burr from the medium stone. Maybe if I took the edge all the way to the fine or ultra fine stone I could finish with just a plain copy paper (no compound) strop. Then again, I may just need to put my 1 and 3 micron DMT diapaste into action. I want to know what you guys think.

Thanks,
Charles

It is possible to completely remove the burr for all intents and purposes with a stone. Some unsupported (burr-like) metal will be left, but it will fall inside the low spots on the grind troughs and can only be totally removed with a surface that has a small amount of give or a loose slurry. From a functional standpoint, it is gone.

You should be able (if the burr is small enough) to finish the edge from your medium stone on plain paper, maybe two sheets will work better, have to experiment a bit. I use it following edges as low as 220 grit or as high as *000 and it always improves them noticeably.

Are you certain the Flexcut is making the burr or is it only revealing or turning up a small existing one. Flexcut needs a lot of purchase to create a burr, and is not aggressive enough to remove larger ones. Some black emery compound after the medium stone might be a better fit. Also, stropping with plain copy paper or newsprint right off the stone is a great way to reveal existing burrs. The smallest will polish up better than the surrounding edge and be much easier to see, especially with a loupe but even with the naked eye and strong light.

HH

ETA: there are no dumb questions about burrs!

 

[Squashfan]

Define "need." It's possible to get a perfectly good, almost burr-free edge without stropping, especially with finer stones. You can get a great, working edge coming off a coarse stone if your apexing and burr-removal technique is up to snuff. But you get to another level with just a little bit of stropping. Do you "need" to do it? Depends on you and what you want from your edge.

Maybe I what I mean is "should I" break out the diapaste. I don't "need" an edge that is more than smooth arm hair shaving. but I WANT the sharpest edge I can turn out.

Mag, how do remove a burr? I have a 154CM Benchmade 940 that I have just taken off of a 400 (IIRC) diamond plate. I have worked hard to remove the burr on the stone but what else would you do?

It is possible to completely remove the burr for all intents and purposes with a stone. Some unsupported (burr-like) metal will be left, but it will fall inside the low spots on the grind troughs and can only be totally removed with a surface that has a small amount of give or a loose slurry. From a functional standpoint, it is gone.

Squashfan says: I think I have actually seen that with a Spyderco Military that I sharpened. It looked like the edge was straight and apexed but when I looked at the edge after I cut something the edge looked coarse again. Not the best description of what happened to me but your description is spot on of what it looked like.

You should be able (if the burr is small enough) to finish the edge from your medium stone on plain paper, maybe two sheets will work better, have to experiment a bit. I use it following edges as low as 220 grit or as high as *000 and it always improves them noticeably.

Are you certain the Flexcut is making the burr or is it only revealing or turning up a small existing one.

Squashfan says: I will bet anything you are right about it turning up an existing burr. I will have to be more careful next time.

Flexcut needs a lot of purchase to create a burr, and is not aggressive enough to remove larger ones. Some black emery compound after the medium stone might be a better fit. Also, stropping with plain copy paper or newsprint right off the stone is a great way to reveal existing burrs. The smallest will polish up better than the surrounding edge and be much easier to see, especially with a loupe but even with the naked eye and strong light.

HH

ETA: there are no dumb questions about burrs!

 

[Magnaminous_G]

I can only speak for my own technique, but once I have a burr worked up on both sides, I then start to reduce the burr. This involves minimal sharpening on one side, just enough to "flip the burr" (not actually flipping it, but rather eliminating it and barely bringing it up again on other side) and repeat back and forth with lighter and lighter pressure and fewer and fewer strokes until just "kissing" the stone in feather-light, 1-to-1 strokes. Then alternating backhoning strokes.

Throughout this process, I'm checking regularly with my fingertip pads. I go until I can't feel any burr at all anymore, and then i do a little more. That usually does it, although sometimes I still discover I didn't get it all.

 

[Jason B.]

Is it possible to refine the burr so much that the edge wouldn't need stropped on a loaded strop?

Yes, you just sharpen with lighter pressure.

 

[Squashfan]

I can only speak for my own technique, but once I have a burr worked up on both sides, I then start to reduce the burr. This involves minimal sharpening on one side, just enough to "flip the burr" (not actually flipping it, but rather eliminating it and barely bringing it up again on other side) and repeat back and forth with lighter and lighter pressure and fewer and fewer strokes until just "kissing" the stone in feather-light, 1-to-1 strokes. Then alternating backhoning strokes.

Throughout this process, I'm checking regularly with my fingertip pads. I go until I can't feel any burr at all anymore, and then i do a little more. That usually does it, although sometimes I still discover I didn't get it all.

I hadn't thought of doing a couple more light strokes after the burr is eliminated! That is a good idea that I will have to try.

Magnanimous G, Heavy Handed and Knifenut1013 thank you for the help! I really feel like I have improved my sharpening over the last couple of months and it is thanks to all the wonderful advice I have received off of Bladeforums.

 

[HeavyHanded]

I hadn't thought of doing a couple more light strokes after the burr is eliminated! That is a good idea that I will have to try.

Magnanimous G, Heavy Handed and Knifenut1013 thank you for the help! I really feel like I have improved my sharpening over the last couple of months and it is thanks to all the wonderful advice I have received off of Bladeforums.

You are heartily welcome, am glad my ramblings are of benefit.

My final thought on burr removal - I tend to think of them as like a door with very stiff hinges, though in fact they might be more like the tip of a Hershey's kiss. In any event, their eventual removal is taken into account as I progress through a given sharpening chore - I know it'll be there and will have to be eliminated with an intentional effort. It is an unavoidable part of the process, might as well plan for it.

As I work I like to raise the burr as even and small as possible - one of the major reasons I work in small stretches and areas of the edge. Then I flip it, once.

Like any piece of folded metal, the more times I flip it the weaker the attachment point will become - that stiff hinge will loosen up. I need a minimum amount of abrasive action to remove it, and that means a minimum amount of pressure. That amount has to be enough that the abrasive can do its job, but not enough that the burr flips on its hinge. I always shoot for a complete removal after one flip so the attachment point will have the most possible strength and I'll have the largest margin of error, relatively speaking (we're talking about a couple ozs of pressure max). Not always possible, but the more times it flips, the tougher its going to be to completely eliminate it.

I also find I have a bit more angle control on one side of the bevel than the other, so that's the side I push the burr to for a final grind-down. Final burr removal is always edge leading on a hard stone. On waterstones, jointer stones, lapping boards, it becomes more possible to remove with a trailing motion. I always finish a sharpening job with some trailing passes on compound or stone debris if possible, or at least some plain paper. The plain paper is merciless for revealing latent burrs and does a great job of stepping up an edge no matter what finish level its been sharpened to (I'm repeating myself again...).


If I'm doing a larger job - lowering the inclusive angle etc, where I can expect a larger or non-uniform burr, I'll work both sides back and forth till I reach the apex at the new angle, and then occasionally I'll raise the spine a few degrees to get a better angle on the burr. Grind it down a touch, then drop back down to the original angle to completely eliminate it with a bit more care - this speeds up the process a bit by allowing a larger margin of error for pressure and fine angle control when the burr is too large to be eliminated quickly.

If its a real coarse edge for tough work that's going to trash it several times over the course of the job, I'll use a microbevel off the rough stone and leave it at that (this is the only time I use a microbevel). I'm not real concerned about a few small burrs in that situation, just want to get a usable edge back in the game as quickly as possible. FWIW, for some "regular" (non-abusive) jobs this is an ideal edge for a tool, and in those cases I'll take a few extra minutes and completely remove the burr the deliberate way. Stropping on a few sheets of paper does a great job of hitting all the irregularities along the cutting line.

 

[Squashfan]

Wow, another great post, Heavyhanded. It will take me a while to process it though. My problem is I am having to reprofile almost every knife I am sharpening because most of them have never had a proper sharpening. They either still have the factory bevel or are pawn shop/flea market rescues.

 

[Chris "Anagarika"]

Martin,

You might want to add the excellent tips to your WB thread!

Thanks! Sometimes having it explained from a different perspective clears out things :thumbup:

 

[HeavyHanded]

Wow, another great post, Heavyhanded. It will take me a while to process it though. My problem is I am having to reprofile almost every knife I am sharpening because most of them have never had a proper sharpening. They either still have the factory bevel or are pawn shop/flea market rescues.

Martin,

You might want to add the excellent tips to your WB thread!

Thanks! Sometimes having it explained from a different perspective clears out things :thumbup:

Thanks, I hope its helpful, I can blab on about basic sharpening for a loong time. Maybe I should paste it to the WB thread. I figure if my posts are helpful enough, folks might wander over to the link in my signature - I cover a lot of this in my videos (where I also show folks exactly how to use a novel, effective, and comprehensive sharpening system available for a very reasonable price)...

Would be nice not to loose track of stuff though, I'm not very good with the search function...


What are you using for a coarse stone? Doing all those fresh bevels will give you a lot of practice working off larger burrs, that's for sure. I highly recommend the coarse side of a combination SiC stone, used with oil. This is where you might want to raise the burr and use that micro-bevel method to shrink them down a bit before working them off. The basics still apply re working the edge in sections, not allowing it to flip too many times, and planning for the burr to show up in the first place.

When doing a heavy fix or serious change of inclusive angle, I'll frequently make a few swipes to keep any burrs down to a manageable size as I work. Sometimes its not possible to make a uniform, small burr, so it might be necessary to keep trying to raise a burr in one spot while reducing a larger one right next door. If you get used to feeling for them with your fingertips, you'll get pretty good at identifying them as you whip em up, and you just flip the edge real fast to reduce any early starting areas by hitting them with light pressure at a higher angle (don't want to flip them, just shrink in place), flip back to the side you're working on - repeat till the entire side can be evened out. Most of the time they aren't that bad, but if the blade has small warps or needs a lot of stock hogged off that strategy can come in real handy. Very useful to inspect the blade before doing anything and make a plan in your head of how its going to flow.

As I respond, am beginning to wonder if my sharpening strategy isn't more of a burr strategy. I just think of the entire process not as sharpening, but as the creation of the smallest, most even and most stable burr possible (at the apex of the flattest, most even bevel sides I can manage). The culmination is its removal in the most simple and complete manner. After that I move on to more of a polishing operation (when applicable) where my goal is to stay right on the hairy edge of creating a burr as I shrink the apex down (backhoning on waterstones/jointer stones, Washboard/hard "strop").

 

[Omega Leather Works]

My problem is I am having to reprofile almost every knife I am sharpening because most of them have never had a proper sharpening.

We are all in the same boat. Until you pick up on what a good strategy is (in terms of acuity) for specific steels and uses, I recommend 30° inclusive. Once you start applying specific angles to specific steels, for specific purposes, THEN it gets kooky.

A really well sharpened traditional multi bladed knife is a good example. I have been putting different edges on each blade because I use each one for a different purpose. Now if only they'd make one with purpose driven steels on each of those blades...

 

[Starik]

After a few cuts, do you pretty much lose whatever you gained from stropping? The reason I ask is because I'm not very good at stropping, and I want an excuse to not do it

 

[Omega Leather Works]

Stropping isn't necessary at all. It can cause problems like hiding a burr in plain sight by standing it up. Once you get a clean apex a (good) strop can go a long way to refine that edge. It's also a great way to maintain an edge. I'm a big believer in stropping, but just like with sharpening, it takes practice. There's a good sticky at the top of the page I believe.

Also, I don't bother stropping much on my high wear resistant high alloy and super steels.

 

[HeavyHanded]

After a few cuts, do you pretty much lose whatever you gained from stropping? The reason I ask is because I'm not very good at stropping, and I want an excuse to not do it

It all depends on the edge you're using. For a coarse edge and hard draw cutting, you probably don't want to bother. When it comes to medium or fine edges, you'll only make the edge better, and you won't see it dull or loose efficiency any faster for being stropped if done well. Generally it will help extend the life of an edge in use, and make a noticeable improvement to start. If you don't like stropping (so far), just try a sheet or two of regular copy or writing paper wrapped around your stone and give that a go as a final step to a regular sharpening. Its a good way to start and very difficult to cause any harm (make sure there's no loose grit under the paper). Don't go crazy, but you can use the same amount of pressure you might use on your stone, or maybe a little bit more. Even on a very rough edge it won't hurt the drawcutting ability and you'll see an improvement in how it cuts in general on any clean edge - this won't do much for a used or dulling edge, will need some abrasive action for that.

You can certainly get by without stropping, but it makes for a very fast and effective way to keep an edge cutting well with less steel ground off. Also a good way to get into trouble if not careful, there are a ton of variables.

 

[Squashfan]

Thanks, I hope its helpful, I can blab on about basic sharpening for a loong time. Maybe I should paste it to the WB thread. I figure if my posts are helpful enough, folks might wander over to the link in my signature - I cover a lot of this in my videos (where I also show folks exactly how to use a novel, effective, and comprehensive sharpening system available for a very reasonable price)...

Would be nice not to loose track of stuff though, I'm not very good with the search function...


What are you using for a coarse stone? Doing all those fresh bevels will give you a lot of practice working off larger burrs, that's for sure. I highly recommend the coarse side of a combination SiC stone, used with oil. This is where you might want to raise the burr and use that micro-bevel method to shrink them down a bit before working them off. The basics still apply re working the edge in sections, not allowing it to flip too many times, and planning for the burr to show up in the first place.

When doing a heavy fix or serious change of inclusive angle, I'll frequently make a few swipes to keep any burrs down to a manageable size as I work. Sometimes its not possible to make a uniform, small burr, so it might be necessary to keep trying to raise a burr in one spot while reducing a larger one right next door. If you get used to feeling for them with your fingertips, you'll get pretty good at identifying them as you whip em up, and you just flip the edge real fast to reduce any early starting areas by hitting them with light pressure at a higher angle (don't want to flip them, just shrink in place), flip back to the side you're working on - repeat till the entire side can be evened out. Most of the time they aren't that bad, but if the blade has small warps or needs a lot of stock hogged off that strategy can come in real handy. Very useful to inspect the blade before doing anything and make a plan in your head of how its going to flow.

As I respond, am beginning to wonder if my sharpening strategy isn't more of a burr strategy. I just think of the entire process not as sharpening, but as the creation of the smallest, most even and most stable burr possible (at the apex of the flattest, most even bevel sides I can manage). The culmination is its removal in the most simple and complete manner. After that I move on to more of a polishing operation (when applicable) where my goal is to stay right on the hairy edge of creating a burr as I shrink the apex down (backhoning on waterstones/jointer stones, Washboard/hard "strop").

HH, the knife I am currently working on is a 154CM Benchmade 940. I started the re bevel on my standard stone but it wasn't cutting metal fast enough. I would say it cut about like a fine diamond stone maybe a touch little finer. This is my standard stone and I have no clue what abrasive it is: http://lansky.com/index.php/products/combostone-2-x-6-copy/ I moved to a medium grit diamond stone to make the work go faster and, while I was thinking about going to the fine diamond, I may go back to the medium stone and make sure I have the burr off by using one of your techniques.
Let me ask a question of you HH. Who makes a good SiC stone?

 

[HeavyHanded]

HH, the knife I am currently working on is a 154CM Benchmade 940. I started the re bevel on my standard stone but it wasn't cutting metal fast enough. I would say it cut about like a fine diamond stone maybe a touch little finer. This is my standard stone and I have no clue what abrasive it is: http://lansky.com/index.php/products/combostone-2-x-6-copy/ I moved to a medium grit diamond stone to make the work go faster and, while I was thinking about going to the fine diamond, I may go back to the medium stone and make sure I have the burr off by using one of your techniques.
Let me ask a question of you HH. Who makes a good SiC stone?

In my opinion, the Norton Crystalon is the most useful of the combination stones, maybe the all time most useful single sharpening tool ever made. The Norton is rated 100/280, but is capable of much finer edge than one might think.


I don't know what the Lansky combo stone is, probably AlumOx? Not to discourage you from buying the Norton, but the coarse side of the Lansky should work well enough on that steel, faster than a medium diamond. Are you using any oil or similar to keep it from loading up? SiC or AlumOx will load, especially on longer jobs, a few drops of mineral oil can make a huge difference. I swear by the drug store mineral oil - its higher viscosity than some, but not so high that it impedes the grinding action, and it stays on the stone/floats debris better than thinner oils.


One last tip re burrs that is very helpful - once I have the burr worked to one side and am ready to eliminate, it helps to lightly backdrag the edge along some wood at a fairly high angle - scrape it along the entire edge at 60 degrees or so. This will make the burr stand even higher to the side I'm working, making it even easier to see and remove. If I am doing a fast grind job with lots of metal removal, I might use a bit of pressure while doing this. As I progress up through the grits I use less pressure. By the time I'm using my Washboard for a final polish/burnish, I'll only be using the weight of the blade or so. Not all steels need this extra touch, but BMs 154cm might fall into that category.

Edit to Add: The link in my signature to the sharpening tool I make, has a couple of video that might help out whether you're interested in the product or not (I know, not another sharpening video!! but I do go into some detail re burrs etc). Wrapping sandpaper around a hard surface - steel, glass etc will give you a surface similar enough to the WB that you could use the video tips ver batim - just start on the second vid, the first one is me talking about the specifics of the product. Mention this because 220 or even 320 wet/dry sandpaper is more than capable of working 154cm as well, just keep the paper clean.

 

[Squashfan]

In my opinion, the Norton Crystalon is the most useful of the combination stones, maybe the all time most useful single sharpening tool ever made. The Norton is rated 100/280, but is capable of much finer edge than one might think.


I don't know what the Lansky combo stone is, probably AlumOx? Not to discourage you from buying the Norton, but the coarse side of the Lansky should work well enough on that steel, faster than a medium diamond. Are you using any oil or similar to keep it from loading up? SiC or AlumOx will load, especially on longer jobs, a few drops of mineral oil can make a huge difference. I swear by the drug store mineral oil - its higher viscosity than some, but not so high that it impedes the grinding action, and it stays on the stone/floats debris better than thinner oils.


One last tip re burrs that is very helpful - once I have the burr worked to one side and am ready to eliminate, it helps to lightly backdrag the edge along some wood at a fairly high angle - scrape it along the entire edge at 60 degrees or so. This will make the burr stand even higher to the side I'm working, making it even easier to see and remove. If I am doing a fast grind job with lots of metal removal, I might use a bit of pressure while doing this. As I progress up through the grits I use less pressure. By the time I'm using my Washboard for a final polish/burnish, I'll only be using the weight of the blade or so. Not all steels need this extra touch, but BMs 154cm might fall into that category.

Edit to Add: The link in my signature to the sharpening tool I make, has a couple of video that might help out whether you're interested in the product or not (I know, not another sharpening video!! but I do go into some detail re burrs etc). Wrapping sandpaper around a hard surface - steel, glass etc will give you a surface similar enough to the WB that you could use the video tips ver batim - just start on the second vid, the first one is me talking about the specifics of the product. Mention this because 220 or even 320 wet/dry sandpaper is more than capable of working 154cm as well, just keep the paper clean.

I oil all of my stones with Norton's natural honing oil BUT I may not be oiling the Lansky often enough because you say it should cut quickly. I would oil every two or three times I changed sides of the blade. That is a lot of sharpening between oils, isn't it?

But if a coarse side works faster than diamond shouldn't the stone over grind soft steels? IDK what kind of stone it is but the scratch pattern won't lie. I think I will to try and see what I get.

 

[HeavyHanded]

I oil all of my stones with Norton's natural honing oil BUT I may not be oiling the Lansky often enough because you say it should cut quickly. I would oil every two or three times I changed sides of the blade. That is a lot of sharpening between oils, isn't it?

But if a coarse side works faster than diamond shouldn't the stone over grind soft steels? IDK what kind of stone it is but the scratch pattern won't lie. I think I will to try and see what I get.

That's a good question. If used with some oil it should develop a bit of lapping action - loose grit rolling around on top of the stone surface as well as the surface of the stone itself grinding away. One of the benefits of using a vitreous stone. This allows it to "eat" some of the burr formation and also not scratch as deeply into the steel despite being a larger size per particle, very much like a waterstone. Seems to work best with a fore and aft stroke. In my experience, SiC breaks down a lot faster than AlumOx, and some of the better AlumOx stones (india) don't really break down at all by comparison, so this factor has to be learned by trial and error per stone. And 154cm isn't really a soft steel, even if it does tend to whip up some stubborn burrs.

I like to use a fair amount of oil, the stone should have a film on top if not a puddle. I also use a short pass - an inch or two - and a scrubbing sort of stroke, so the oil tends to stay put until I start wiping the blade more often as I increase observation prior to finishing. At that stage I don't need to maintain a puddle, and can deburr with a damp stone or even a mostly dry one. Just keeping it moist will protect the stone from impacted metal, but might not keep it grinding well. The extra oil also helps keep a real light touch, making it less likely the stone will overpower the steel. I have only had that happen to any extent on really soft kitchen cutlery, will not be an issue for most jobs and will be obvious when it begins to happen.

Sounds complicated but it really isn't. I suspect I sound like I'm throwing too many answers to a simple problem, if so I apologize. Go by feel and experiment a bit. Again, I have no idea what the Lansky is, but have worked all kinds of steel with cheap AlumOx stones. It goes back to another one of my major principles - all grinding produces swarf, if it isn't accounted for, it will negatively effect your progress. This factor increases as the amount of steel removed increases and is a major cause of sharpening frustration. Whatever you're using it will pay off in time saved and a cleaner grinding action if you can keep the crud from building up. If that doesn't help, time to try a different media.

It might just be that your stone isn't up to it, but most manufactured stones are very capable on most steel. Some slower than others but should still work fast enough to note reasonable progress. On larger jobs like you have going on, sometimes you just have to hunker down - a good time to closely examine your technique/form and see where it can be streamlined.

All of the above illustrate why I recommend the Crystalon stone, not flashy, but it tends to produce very predictable results across a very wide range of steels and very little can confound it .

Martin

 

[Squashfan]

I am not seeing swarf formation because I don't keep a puddle of oil on top. I keep the stone wet to the touch and that took almost a full 4 oz bottle of oil the first time I used the stone. Besides, this stone eats oil and is very, very porous. I almost think oil just passes through it. I have to keep a plastic tray under it or the counter gets covered in oil.
Anyway, I did sharpen the 154CM blade last night. I put a really nice scratch pattern on the edge. Maybe it is the way I treat the stone by not keeping it really well oiled but the Lansky's scratch pattern looks finer than the medium diamond. Maybe, by not oiling it, the stone becomes finer. I could almost strop this current edge with black compound and call it quits. But where is the fun in that? I am going to strop on plain copy paper to reveal the burr and work it off some more before moving to the next stone.

By the way, this stone is starting to lose its flatness. It is still pretty flat but I can tell there are high spots at the ends with a slightly more aggressive grit. I am not sure that this stone is AlumOx. It is does not seem to be behaving like your descriptions but that may be my fault. But I like it what ever the abrasive is. It does a great job on 154CM.

Thanks,
Charles