Sharp Talk: Honest Musings and Mad Ramblings

There aughtta be a name...for the flare in the grind you get at the plunge line when lowering the angle on a sabre grind.

Am pondering the differences between guided and freehand edges and am beginning to wonder if a bit of noise in a guided system might not greatly improve things.

The following comments are related to my observations, others might have different experience. They also fall under the heading of "Mad ramblings"!

Guided manual sharpeners are slower than freehand, considerably in some cases.

This being due to the need to flatten completely the entire bevel surface before grinding a fresh apex. In situations where the edge is uneven and the angle not being changed, guided systems create large burrs in some places and none in others until that last bit of edge is trued up. Yes, subsequent sharpenings will have very small burrs or none at all, but the initial go-to is a different story.

Cosmetically, the guided edge shows more of the imperfections in the primary grind as it came from the factory. Slight changes of angle - to rapidly remove a burr for example, show as unsightly secondary bevel swipes along the edge drifting back into the just-ground cutting edge.

I do not believe my guided edges are any better than my freehand edges although much easier to craft. One can lock a given blade in and go have a sandwich, when you come back its still there ready to go. It comes in handy when you're tired and just need to get some work done - you supply the technical know how and the widget takes care of the precision part. Cosmetically the edge grind looks cleaner than all but the finest of freehand work.

This brings me back to creating some noise in the system that might actually allow for faster sharpening and smaller burr formation. Having a slight rock will make a minuscule convex (1-2 degree or so) that should allow for more rapid grinding to the apex. This might also decrease burr formation in the already ground regions as the hone isn't relentlessly hitting the apex with the full stroke of every pass. Not to mention the CATRA testing that showed a slight convex improved edge retention (all else being equal).

With my system I could build a very slight sweep in the guide bar so at the middle of the stroke the angle is most acute, and increases at the ends. Is also possible to incorporate a gentle wave pattern that undulates a degree or two in a string. Need to mention although I'm not sure it is important - with the above scenario I'm altering the fixed point of the blade itself, the blade is changing angles, not the stone - just as it would with freehand work.

I am trying to wrap my head around if this is any different from sharpening with a dished or loaf shaped stone on a mast/arm type system, or bending the guide arm slightly. Superficially it would seem to be the same, but I'm thinking there might be some fundamental differences. With the system I am describing, the stroke doesn't need to be defined, but with a mast and arm system you would need to have a hard stop on the travel at the most acute portion of the contact path...maybe:confused:
 
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HeavyHanded said:
In situations where the edge is uneven and the angle not being changed, guided systems create large burrs in some places and none in others until that last bit of edge is trued up. Yes, subsequent sharpenings will have very small burrs or none at all, but the initial go-to is a different story.
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This is why I first repair the profile of a knife by grinding perpendicular to its flats, before working on bevels. (I have heard this called bread-knifing because it looks a little like you are trying to slice the stone in half.) This way I can stop grinding as soon as the flat edge stops reflecting light, and I still have a nice even edge profile.

HeavyHanded said:
This brings me back to creating some noise in the system that might actually allow for faster sharpening and smaller burr formation. Having a slight rock will make a minuscule convex (1-2 degree or so) that should allow for more rapid grinding to the apex.

I am trying to wrap my head around if this is any different from sharpening with a dished or loaf shaped stone on a mast/arm type system, or bending the guide arm slightly.
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On the Wicked Edge forum I proposed this:

There is a (conceptually) simple solution to this: make a plate with a subtle undulating ripple along its long axis. This will give a continuously changing angle that combined with moderately different strokes should produce a convex edge in a nicely controlled range.

Rough calculation indicates that with one ripple (up/down) per inch you only need about 0.55mm peak-to-trough to give 10° of variation.
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This assumes an abrasive that does not appreciably wear, like plated diamond.
 
HeavyHanded HeavyHanded well at least I ask easy questions. :p:D

In all seriousness, that's a really interesting idea. I wholeheartedly concur that the initial sharpening on a guided system can take quite some time and that it is due to getting a "truer" bevel grind if you will. I think we see this reflected here often when people post about whatever system they just acquired and lament how long it is taking them to achieve a good edge. Often this gets chalked up to stone size, which of course plays its part, but it is more than that. Often I think this gets even more clouded as typically these folks are also trying to accomplish a re-profile on their first attempts and people key into that aspect. Because of this, and bolstered by the "burnt edges" discussion, I think going forward my advice to folks about systems will be to just focus on cleaning up the factory bevel and their angle for a couple sharpenings before considering re-profiling. It's bad enough just doing that without trying to remove all that additional material.

I used to think I'd use my KME for re-profiling for the precision and evenness of it but have since moved away from that notion. As my skills and understanding of freehand sharpen grow, I find myself moving further and further away from the guided systems. In no way is that a knock on them and my KME isn't going anywhere any time soon. When I'm sharpening for others I'll sometimes still pull it out as I have so much confidence in it's ability to achieve such fine (and impressive) edges. As my free hand confidence grows though, I get bolder.

All that said, if I'm following along with you correctly, I'd say that for an enthusiast sharpener, like myself, there wouldn't really be a reason to pursue what you're pondering. To me, the primary advantage, if indeed there is one, to what you're saying is really speed. That's obviously a real concern for someone like yourself who has a time-is-money perspective, but I would think that for someone like me, the trade off of intentionally inducing some "slop" in the guided system would just be fighting against it's primary benefit; precision. Not that any of us are going to start trying to mod our purchased systems to have some slop, just saying... :)

But I think it should work provided you can keep it somewhat constant. The KME convex sharpening tool is just a bent arm and they say it creates a few degrees of difference.

And thanks for jumping in. :)
 
Eli Chaps Eli Chaps

The guided system I use incorporates full size stones, but either way, yes it takes longer to reprofile. Another factor is that I really believe the perfectly flat bevels from a guided system are somewhat less robust than freehand edges.

M Mr.Wizard the flattening tip is a good one in this context. that would help with everything but warps, which a pain even with freehand though to a much lesser extent. I'm not even sure noise in the works would help much with that. Just have to work the long edge of the stone if you don't want to grind the whole thing out, and that is beyond the specs for most sharpening IMHO.

Yes, most of the time now I don't even bother with my guided system, which is why it takes me so long to ponder the remaining issues I have with using it. But, when my neck is acting up, I have enough knives that it makes sense to use the belt grinder, or the dollar value of individual knives is way up there and they are obvious collectibles, I tend to reach for the clamp. Plus I break it out every so often just to stay good with it.

Just musing if my freehand edges are as good or better, what can be done to "freehand" up my guided system. I'll give it a go and get back.
 
Chris "Anagarika" said:
HeavyHanded HeavyHanded
I’m wondering if the final angle at the apex is the same, would the flat bevel still be less durable than the free handed convex?
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I'm not entirely sure it is less durable, but my theory is that if you repeatedly hit the apex at a slightly different angle, say half a degree or so, it makes the edge develop more cleanly. I'm not sure why I think this, just that even using (probably) more pressure when I freehand, I have smaller burrs and they seem to come off easier. I haven't figured out why, so down to speculation.

Almost as if the precision apex generates a weaker burr attachment that flops more readily...or something.

Or it might all be my imagination. But this isn't the first time I've thought adding some noise would be a good thing if it could be made random enough.
 
HeavyHanded said:
I'm not entirely sure it is less durable, but my theory is that if you repeatedly hit the apex at a slightly different angle, say half a degree or so, it makes the edge develop more cleanly. I'm not sure why I think this, just that even using (probably) more pressure when I freehand, I have smaller burrs and they seem to come off easier. I haven't figured out why, so down to speculation.

Almost as if the precision apex generates a weaker burr attachment that flops more readily...or something.

Or it might all be my imagination. But this isn't the first time I've thought adding some noise would be a good thing if it could be made random enough.
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I used to notice this when I was using a guided system for sharpening, like a Lansky, Aligner, etc. With the guide, I developed some freakishly thin & very wide burrs, or more precisely, aligned-straight 'wire' or 'foil' edges, which then would just crumble off onto my fingertip when I felt the edge. These wire edges held on a lot longer than if I'd been freehand sharpening, from which the variation in angle from pass-to-pass would act to break away the wire much earlier. So, even if the edge apex itself was more precise & thin using the guide, I always tended to believe it's thinness also left it more fragile than the edges I later attained in freehand sharpening.
 
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Obsessed with Edges said:
So, even if the edge apex itself was more precise & thin using the guide, I always tended to believe it's thinness also left it more fragile than the edges I later attained in freehand sharpening.
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The best edges I get on a guided system all incorporate a microbevel. While I do use a micro quite often freehand, I also use single bevel and these are definitely better done freehand.
 
Very interesting ideas about the apex formation. Now that I think about it, it’s true that when I sit down and concentrate on the sharpening process meaning that the angle control is improved over “hand held just make it sharp again quickly”, I seem to develop a bigger and more stubborn burr, I’ve never thought about it until reading you guys, but maybe it’s due to the slight variation or microconvexing, great analysis!.

On another topic, I was curious about the sharpness of the blades I use for whittling wood, of course they’re damn sharp and more than enough for the job at hand, which is slice through the wood as effortlessly as you can while maintaining the edge stability and leaving a glassy surface on the working piece.
I’ve whittled hairs before with other knives, following a water stone progression plus strop, just for show, but I wanted to test the capabilities of the on the go routine which is usually:
- restablish the bevels with the diamond on the dc4 (25 microns)
- polish with an Opinel natural stone, handheld light pressure and quick back and forward motion
- remove any burr remaining with super light edge leading
- around 20 passes on leather or paper over the stone with white compound light pressure same angle or slightly under
- around 10 passes on clean leather (usually boot or belt)
Total time is around 3-5 minutes depending on burr removal.


Anyway, it’s sharp ;)
By the way, it’s 1095 by GEC at around 58hrc.
Thanks, just an honest rambling.
Cheers
 
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lutejones lutejones thanks for jumping in. :)

I think the perspective of wood cutters is very valuable. Not only is it a rather hard medium, but there's also flexes and stresses on the edge that many other cutting applications don't produce.
 
I hope I am not jumping in at the wrong place but just want to say t
hat the info in this forum is fantastic. I have been sharping knives for almost 40 years. I was not able to get to a real good edge until a former navy seal who had been injured and was going back to college took the time to show me how to work a bench stone. I was able to keep those skills up until kids came along. When my son joined cub scouts 6 years ago I started trying to sharpen again but with bad results. I read the stickies here and then hit myself in the head. The instruction around the campfire came back. Then adding the sharpie to the blade edge and the loops to see what you are doing really get the knives sharp. I spent last weekend teaching scouts what I have learned here.now I am working with leather strops and keeping the kitchen knives sharper between stone time. Thanks to DN my old stones are backe to peak performance. Although I have added the dmt diamond duo sharp for my kitchen knives so I am not spending hours every few moths grinding them on my stones. All ot this being said the more I learn the more I don’t know. But it is fun when you work with a young scout and see their face light up when they effortlessly slice that piece of paper for the first time. My son just did it tonight. My daughter intends to do this this weekend after finals are over with. Later on I will need to post qustions on ,making my own strops as the first one I bought has suffered from my mistakes
 
"My Way or The Highway..."

When last we met, I was professing how I'd been moving away from using my KME for e-profiling. And while that is true, I also in no way abandoned it. It seems the debate about guided systems vs. freehand is destined to be never ending. I think that's a shame and I think that when folks declare absolutes for whatever side they fall on, they are both missing what I think is the point, and not helping those who are inquiring.

Don't get me wrong, I'm not saying one should not advocate for a preference or highlight the benefits of their preferred method, I'm just talking about those who ardently oppose one approach over another.

Those who are prone to such staunch assertions have predictable arguments.

The fervent Freehanders generally assert that it isn't hard and you won't have that gizmo all the time. I always wait for the "bottom of a coffee mug" statement to come into play.

The fervent Systemites generally assert the superior precision of their method.

In my mind, there's room in the sandbox for everyone. I like both approaches and use both methods. I think that is a person wants to delve into sharpening, that's the most important thing. The overwhelming majority of knife users couldn't care less about sharpening, and that includes a lot of "enthusiasts" so if someone expresses an interest and comes looking for guidance, I say give them the pros and cons but not absolutes. Guided systems can give great results and can lead to a desire to learn freehanding and help in understanding fundamentals.

I do think discouraging folks from buying junky or restrictive systems is a good idea.

Not a great pic, but this is a Dexter Russell knife I've been toying with for some time. I've been messing around with thinning the blade and laying back the edge and up until now have done it all freehand. But I decided I wanted to lay the edge back even further and while I could've done it freehand, I decided to just clamp it up and give it some work while I watched a Rough Rooster Knife Sharpening video. :)

4cWUPal.jpg


Anyway, I guess my point is let's just get people excited about sharpening. It can be intimidating and overwhelming when first exploring the subject and it can be, as I've demonstrated in this thread, frustrating. So helping folks along, regardless of method, is what I think is most important.

:)
 
My kids and one of my grand nieces and nephews (brother/sister) were over tonight. They're all about the same age (20's) and very close.

I'm in the kitchen tending to my homemade chicken soup when my grandniece comes up and presents a pink-camo'd little Buck folder. Not sure it's even still made but thumb studs, mid-back lock, probably around 2.5" blade. Anyway, she informs me that her "Na-nuh" (my sister) needed a knife the other day and when she handed her this one my sis promptly gave it back and said it was too dull. My grandniece informed that one of her other uncles tried to sharpen it for her once.

Ugh.

I get dinner self-propelled and come back out into the living room to see what we've got. I said to my grandnephew that I really want to, "teach all you kids how to sharpen." He enthusiastically replied, "I'm down with that!"

He spent a summer with his grandpa and grandma (my brother in law and sister) fully restoring an old Plymouth Duster so the kid is serious when he says he wants to learn.

I had a 300 grit diamond stone within arm's reach so I pulled up a TV tray and my grandnephew slid his chair right up to the table. The edge bevel on this poor guy was pretty trashed and it also had a slight recurve at the back of the blade as Buck was so insistent on doing for a while. We talk blade nomenclature, we discuss the idea of what we're doing when we sharpen (apex, burrs, etc.), we talk angles and all of it. I showed him how to mark the bevel with a marker and let him see me removing it. I told him how factory bevels suck and are often very uneven. I show him where her other uncle couldn't hold an angle. He was wide eyed and eager.

I ground out a fair bit of the recurve but was struggling to get a good burr he could feel. Fearing he'd think I was cracked, I got up and grabbed my Norton India stone. A much better fit for that steel. A couple minutes later he was running his fingers over the burr and telling me where it hadn't formed. We talked about edge leading vs. trailing, touched on stropping philosophy and within a few minutes, he was all smiles about how sticky the blade was on his thumb nail and how easily it sliced receipt paper.

My grandniece was happy and my grandnephew promised to come over for a bonafide lesson next time he's home from college. He was super into it.

I don't mind saying that it's a little nerve wracking being watched and proving results! When I was struggling to get that 420HC to burr up the way I wanted on the diamond, I couldn't help but think my grandnephew might think I'm full of it. But then it all came together and he was stoked.

I have no doubt he'll be back and I'm very much looking forward to it!

:)
 
If you're going to demo sharpening method, you need a coarse stone and or a knife you've already sharpened.

I once showed a coworker how to sharpen a knife to armhair shaving three times in rapid succession under 5 minutes total, dulling it on a screwdriver shaft each time. Wet/dry and paper on a Washboard, Norton economy stone, and a coffee cup. But this was a knife with good bevels to start.

Otherwise, an 80 or 120 grit stone is a real good idea!
 
HeavyHanded said:
If you're going to demo sharpening method, you need a coarse stone and or a knife you've already sharpened.

I once showed a coworker how to sharpen a knife to armhair shaving three times in rapid succession under 5 minutes total, dulling it on a screwdriver shaft each time. Wet/dry and paper on a Washboard, Norton economy stone, and a coffee cup. But this was a knife with good bevels to start.

Otherwise, an 80 or 120 grit stone is a real good idea!
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Yep, there's a course ceramic of some configuration in my future! :)

I should've started with my Crystolon but thought the diamond would get me there quick enough. Then I felt kinda committed for a few minutes there before changing tactics.
 
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