How to get clean edges off the stone--questions

[Bladenoobie1]

I've been at freehand for almost a year now and in the past few months, my technique has improved considerably as well as my equipment. I have no problem getting phonebook push cutting edges, but I almost always need to finish off my strop. I'm having trouble getting clean edges right off the stone. When finishing off a stone, I try to do extremely light alternating strokes but even then there is more burr than I'd like. Ideally I want to achieve an almost burrless edge before I strop so when I do finish with stropping, I can get a even keener edge then what I'm getting now. Any advice?

- BN

 

[SteelStickler]

check out knifenut's youtube vids, i think its mredgy[eightysomething] - he's got crazy skills and breaks his technique down well. I've heard him say that using less pressure during the entire process lessens the resulting burrs. hope this helps.

 

[Bladenoobie1]

check out knifenut's youtube vids, i think its mredgy[eightysomething] - he's got crazy skills and breaks his technique down well. I've heard him say that using less pressure during the entire process lessens the resulting burrs. hope this helps.

Thanks, but I'm well aware of knifenut's youtube videos and his presence in the maintenance section. He has helped me considerably with my freehand sharpening with the many threads I've posted in this section. The thing is, is that I am using extremely light pressure at the finishing process. Usually what I do is keep working on one side until a new bevel and burr has been created. Then I go to the flip side and repeat the process. Then I alternate sides as needed until I can no longer feel the burr. My final step then is a few alternating extremely light forward strokes. After this I can slice printer paper, but if I try to push cut for slice very slowly its evident that there are still areas with a burr--which then I go to stropping to clean it up.

My goal is just to get keener crisper edges by minimizing the amount of burr there is prior to stropping.

 

[HeavyHanded]

This is from a older thread, but might be useful.

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.

 

[KennyB]

Thanks, but I'm well aware of knifenut's youtube videos and his presence in the maintenance section. He has helped me considerably with my freehand sharpening with the many threads I've posted in this section. The thing is, is that I am using extremely light pressure at the finishing process. Usually what I do is keep working on one side until a new bevel and burr has been created. Then I go to the flip side and repeat the process. Then I alternate sides as needed until I can no longer feel the burr. My final step then is a few alternating extremely light forward strokes. After this I can slice printer paper, but if I try to push cut for slice very slowly its evident that there are still areas with a burr--which then I go to stropping to clean it up.

My goal is just to get keener crisper edges by minimizing the amount of burr there is prior to stropping.

When you're taking the burr off and alternating sides, do you mean you're doine one stroke on one side and then one on the other, or removing the burr from one side, and then on the other? Concentrate on one side at a time until you can no longer feel the burr on it--this will usually push it up some on the other side, so every time you switch sides to "chase the burr" gradually lighten up in pressure.

Then when you're doing a few alternating extremely light edge-leading strokes, do several of these... Maybe a dozen or more? It's hard to get an idea of how much pressure someone is using... I try to make my knife weigh as much as a feather would at this stage.

I finish most of my edges off a 600 grit hone and they shave and split hair and all those fancy tricks.

 

[Bladenoobie1]

When you're taking the burr off and alternating sides, do you mean you're doine one stroke on one side and then one on the other, or removing the burr from one side, and then on the other? Concentrate on one side at a time until you can no longer feel the burr on it--this will usually push it up some on the other side, so every time you switch sides to "chase the burr" gradually lighten up in pressure.

Then when you're doing a few alternating extremely light edge-leading strokes, do several of these... Maybe a dozen or more? It's hard to get an idea of how much pressure someone is using... I try to make my knife weigh as much as a feather would at this stage.

I finish most of my edges off a 600 grit hone and they shave and split hair and all those fancy tricks.

Removing from one side then the other. I've been free sharpening for a year now and I know all the basics and the concepts. It's just more of technique advice that I could use. On another note is it ever advisable to use trailing strokes on the stone to finish off the knife? I tried to do that on my glass stones and I get in an endless cycle of flipping the burr.

 

[KennyB]

Removing from one side then the other. I've been free sharpening for a year now and I know all the basics and the concepts. It's just more of technique advice that I could use. On another note is it ever advisable to use trailing strokes on the stone to finish off the knife? I tried to do that on my glass stones and I get in an endless cycle of flipping the burr.

I avoid edge-trailing strokes at the final stages, because I think they produce wire edges and chasing-burrs as you mentioned. Beyond that, if you ever read verhoven's experiments (http://www.bushcraftuk.com/downloads/pdf/knifeshexps.pdf) it does a good job of explaining why edge-leading strokes remove a burr so much better.

As far as technique goes I'll just describe what works for me... Once you're at that point where you really know that burr is gone from both sides and you start doing alternating strokes from side to side in your final "honing", maybe throw in a little extra attention per side say two or three strokes and not with such great concern with light pressure, but with contact of the apex on the abrasive. I think that in the proccesses of removing a burr, the apex still needs to be refined/established back a bit at the point where the burr was broken off. If you just do one stroke, alternate to the other side, do another stroke and at extremely light pressure I think it just tends to take a bit longer and therefore makes you more prone to shake or screw the angle up, or never actually get the apex to its true optimal point without going over, or degrading it from the burr removal. You're better off after having removed the burr to spend a little extra time and pressure on each side--minding that you don't raise another burr--before alternating side to side with the extremely light pressures. At this stage I really go mostly by the feedback the edge gives me on the abrasive to tell me when I've got that apex fully back with no burr before the final light-pressure honing. Might sound like I'm talking about the technical aspects, but really what I'm saying is that once you're at that point of edge refinement, human error is as such that one pass on one side and you may have not actually hit the apex--or you may have overshot it. There's a certain level of error in my own angle contorl I learn to compensate for in that way, and by doing one or two passes and then alternating it's kind of like suring up my odds that on at least one of those strokes I got a perfect pass on the apex without undershooting or overshooting it. I might be overcomplicating it, but it's hard to describe technique...

Some people do encourage edge-trailing because when you remove the burr, it dosn't tear it off and leave this blunted portion that still needs extra attention to refine back, but I think it tends to just raise a burr out straight and leave a wire edge.

Most of this stuff does ultimately come down to personal preference and what works, there's no real "One way works, this way doesn't". I'm just a fairly strong advocate for ultra light, edge-leading strokes to do the final finishing/honing.

To give an idea of the type of pressure I'm talking about, take a piece of tape and put it between two books, not too tight, not too slack. Then touch your finger to it without making it sag at all...

 

[HeavyHanded]

Removing from one side then the other. I've been free sharpening for a year now and I know all the basics and the concepts. It's just more of technique advice that I could use. On another note is it ever advisable to use trailing strokes on the stone to finish off the knife? I tried to do that on my glass stones and I get in an endless cycle of flipping the burr.

On a softer waterstone you can use trailing strokes to finish with good effect. It is extremely critical of strong angle control and light pressure. Very easy to raise a new burr, or just flop around an existing one. A leading stroke is by far more reliable, but on a softer stone it won't yield the finest edge the stone is capable of. Whether your stone is soft or hard is something you can only determine by experience or solid reputation.

 

[Jason B.]

On glass stones I would probably use edge leading because of how hard they are. In my experience hard waterstones will produce a little more burr and edge trailing strokes don't often work out so well, it can be done but takes a high degree of pressure and angle control.

To better understand how much pressure you are using hold the stone in one hand and the knife in the other. You will be able to use lighter pressure than if on a bench and will give you a good idea of how hard or light you are really pushing.

On a side note:

I see burrs a bit different. To me a true final burr is hanging on a sharp apex and just needs to be "pulled off" to expose the sharp apex and yield a "true edge". I don't really believe in the burr breaking off or damage being caused because, and in most cases I have difficulties subscribing to "the burr caused my razor sharp edge to go dull". Simply by cutting newsprint you can remove small burrs and if that doesn't work the the burr is probably not small enough or the steel too wear resistant (think S90V).

 

[Obsessed with Edges]

On glass stones I would probably use edge leading because of how hard they are. In my experience hard waterstones will produce a little more burr and edge trailing strokes don't often work out so well, it can be done but takes a high degree of pressure and angle control.

To better understand how much pressure you are using hold the stone in one hand and the knife in the other. You will be able to use lighter pressure than if on a bench and will give you a good idea of how hard or light you are really pushing.

On a side note:

I see burrs a bit different. To me a true final burr is hanging on a sharp apex and just needs to be "pulled off" to expose the sharp apex and yield a "true edge". I don't really believe in the burr breaking off or damage being caused because, and in most cases I have difficulties subscribing to "the burr caused my razor sharp edge to go dull". Simply by cutting newsprint you can remove small burrs and if that doesn't work the the burr is probably not small enough or the steel too wear resistant (think S90V).

^Good advice. Especially the first bolded point above; my habits were built around that technique, of stone in one hand and blade in the other. Makes it more difficult to lean too hard into it (hand fatigue will let you know if it's too much), and the burrs will be smaller as a result. Pressure is what creates burrs; more pressure makes them bigger. So, it's best to take steps to minimize them from the outset, and in every following step. This also pays off in stropping on conformable substrates like leather; less pressure minimizes compression of the substrate, and will reduce the likelihood of rounding off the apex.

And the second bolded point is equally valuable as well. If the burrs are where they need to be, off the stones, then they can often be scrubbed off by cutting into paper, or layers of paper, or cardboard, or wood. Which works best will depend on how fine the burr is; I sometimes ascend the scale (as needed), from paper, to multiple layers of paper (or cardboard), to wood, in de-burring an edge.

And there's still no harm in using a strop. Choosing the 'right' compound for de-burring can not only clean those up, but further enhance your edge as well.


David

 

[Bladenoobie1]

I'm currently using a boron carbide hand american paste in 1 micron size on balsa wood. I used to have lots of trouble stropping on leather, often rounding the edge, but the transition to balsa wood has been great.
Thanks for the advice everyone and I'll be sure to do that test to see how much pressure I am really applying.