Sharpening anomaly

[dsvirsky]

Generally, I use a Sharpmaker 204 to sharpen my knives. While I may not get the hair-poppin' results that some do, they do shave when I'm done. All except two: my DDR small Apogee (CPM S90V) and my GT Mini (ATS-34). Doesn't matter whether I use the medium or fine stones, or how long I work; the edge that I put on with the Sharpmaker just won't shave.

Now I realize that blade geometry has a lot to do with whether or not a knife will shave, and that push cutting isn't all there is to "sharp." But that doesn't explain why I've been able to get both these knives to shave (not well, but some, and slicing is improved too) hand sharpening with my GATCO Tri-seps. (For those of you who aren't familiar with the Tri-seps, it's the same ceramic as the medium Sharpmaker stones.) There's no significant difference in the bevel angle -- reprofiling S90V, or even ATS-34, with a 3" piece of medium ceramic would take a lot of work.

Any thoughts?



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Dave

Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon

 

[maury]

I was going to post a similar question - figured I'd tag it on to this one: I just got a Sharpmaker and have been sharpening th eheck out of a bunch of blades. I also can get them to "pretty darn sharp" but not to the legendary "hair poppin' " that I was expecting. Will using th e30 degree angle first help? The instruction video was not too clear on this. Also, have a brand new CRKT Kasper and have had a really hard time getting it to even "real" sharp. Help!

Thanks.

 

[Johan]

This is one of the reasons I stopped using the Sharpmaker. Because of the fixed angle of the ceramic rods, some knives are virtually impossible to get shaving sharp on the 204. If the shoulder of the knife is "fat" or the angle of the edge very wide the edge doesn't make full contact with the rods. You can sharpen the blade, but it never gets really sharp. I used to have this problem with my AFCK. I thought it was the steel, but then I bought an Apex and sharpened it on that. Razor edge and shaving sharp.

The 204 is great for maintaining an edge or sharpening from scratch when the angles match, but if the don't then forget it. You'll be there all day.

Hope this helps.

 

[Hoodoo]

Try using a magic marker on the edge to make sure you are sharpening all the way down to the edge. A good pocket lens will help you see this. 10X is good. You can also get a 30X scope, probably from radio shack. They are just cheep plastic ones with a very limited field of vision but they do work. A good dissecting scope is great but pricey (into the hundreds or thousands of dollars).

If you are sharpening all the way to the edge on both sides (and this could take a LONG time with the Sharpmaker if the original angle of the knife is greater than 40 degrees--you need a gatco or lansky or benchstone or something else to reprofile), than try going one step farther and stropping your knife on a piece of leather smeared with jeweler's rough.


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Hoodoo

I get some pleasure from finding a relentlessly peaceful use for a combative looking knife.
JKM

 

[russ]

sounds like ya definitely gotta re-profile.i use bench stones.Or i get one of my custom knifemakin' buds to do it

.that's the easy way out

seriously, i'd get some good benchstones and practice with a "lesser"knife until you developed your technique.there's nothing like doin' it the old way. great sense of satisfaction too.

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a cat almost always blinks when hit in the head with a ball-peen hammer.
The only thing better than a good knife is a good woman

A few of my Knives
russ aka blade zealot

[This message has been edited by russ (edited 01-21-2001).]

 

[Mykl Clark]

I use a 204 everyday and can achieve the hair popping edge that is so legendary. First I'd suggest reprofiling the edge with a system that uses something a bit more course (benchstones, Lansky, Gatco). then to achieve the Zen edge you have to sharpen it at the 30 degree mark and strop it. I usually don't bother with using 30 degree angle for anything but very fine thin knives as edge retention becomes a problem.

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Mykl
Anxiously awaiting my BM 42A

 

[dsvirsky]

Just to add to the original post, I do use the magic marker method to check that reaching the edge when doing more than a touch up.

I re-profiled the GT Mini down to 30 degrees inclusive (that took some work!), got a burr on both side, etc.. No shaving. Micro-beveled at 40 degrees to strengthen the edge -- no shaving. Picked up the Tri-seps, gave each side half a dozen free-hand strokes, and voila! Shaves.

After using the Apogee to cut a bunch of reinforced strapping tape, it wouldn't shave anymore. Should have just been a touch up, but I couldn't get it back to shaving status, even though it was certainly sharp. So, remembering what worked for the GT Mini, I used the Tri-seps.


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Dave

Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon

 

[jeffa]

I had the same problem with my GT but anything else I have no problem sharpening.
I do agree a couple rough bench stones to reprofile is a good idea. Remember if it is hair popping sharp it will have a very thin edge and has the potential to dull faster. It can still be extremly sharp and not so thin and hold up longer, it all depends what you want to use it for.

 

Hi there,
Some steels are "brittle" to the core, some are a bit little more "flexible" in VERY tiny dimensions (microns & so).
The more "flexible" ones tend to have a last "burr" that just bends back & forth when you use a fine hone, you never get them really "sharp". So, as a last stroke, pull the blade ALONG the edge, as if you were "steeling".
The "burr" cannot yield along the edge, there is no room to go, so you will "scratch" it off.
Use absolute minimal pressure to do so, otherwise you will create a new "burr".(My expression is: just "kiss" it away).
Too much pressure may be an explanation for not getting the ultimate sharpness.
You'll wonder how sharp it may be now.

Happy sharpening

[/b][/QUOTE]



[This message has been edited by ZUT&ZUT (edited 01-21-2001).]

 

[rdangerer]

My experience with Spyderco tends to match Johan's. I use a Lansky for blades up to 5" if the clamp is wide enough (a design flaw, that). My buddy tried my Lansky and likes his Gatco better. Neither is perfect, the EdgePro Apex and Pro look good to me, but I don't own them yet.

Use diamond stones to reprofile the edges. I can get any edge to shave from of course the 15 degree end and even up to 30 degree (not a clean shave, but a much more durable edge for real work). Diamond makes work go faster.

I too have found that last burr to be more "flexible" or springy on some steels.

My final step after a fine diamond is to strop on a very flat leather strop with fine rouge embedded, or on cardboard or back nappy side of one side of a cereal box (which works just fine). You pull the knife away from the edge (NOT like you are trying to slice the strop), once on each side, the goal is to mechanically work the burr back and forth until it comes off in tiny slivers. I can see them come off. Just like bending a piece of wire back and forth until it weakens and breaks.

You also need to ask yourself if you really WANT a smooth, polished edge that rolls hair. I thought I did, but found that if it shaves my arm hair (finer than my leg hair, which is coarser and easier to shave) and I finished on a fine diamond and then stropped the final tiny burr, I get this nice toothy edge that is my preferred edge for real work (not arm shaving).

Do you want to shave? Or impress others with a shaving edge? Or do you want a real toothy edge that works great on things like boxes and rope and zip ties and whatever else. In the end, shaving is a quick test of whether I'm done sharpening or not, but hair popping was not my ultimate goal for my daily carry knives... a good working edge was.

To each, his own.

By the way, my Spyderco 204 Sharpmaker is only used on serrated sections of carry knives or serrated kitchen knives, a task for which it is excellent in my experience. However, anything serrated and 5" and under I can also do with the triangular ceramic stone that I got for the Lansky.
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rdangerer@home.com

[This message has been edited by rdangerer (edited 01-21-2001).]

 

[Crayola]

Re-profiling sounds in order. I am switching sharpening methods over to using my grinder. BUT, after sharpening on the grinder my last step is to use the white ceramic stones on my Sharpmaker 203. If the sharpmaker is someone's only bit of sharpening kit, they should also get a very coarse stone to refprofile edges with too. This is a very necessary bit of kit. Grind in a good relief and it won't take long to get great results with your sharpmaker.

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"Come What May..."

 

[dsvirsky]

I appreciate everyone's input, but I don't think I successfully got my question across.

I'm not asking how to get my knives shaving sharp -- I can get most of them to that state, and any lack of "hair-popping" may well be due to the fact that what little arm and leg hair I had before knife sharpening is quite fine -- and I'm not even saying that I want a shaving edge on the Apogee. While I keep thin-bladed small folders (e.g., WH CF Lancet or CRKT Ti Mirage) shaving sharp, for a working knife I prefer to use Joe Talmadge's method of sharpening to a polished edge, and then going back to the medium stones for a few light strokes to rough up the edge for slicing. Shaving is just a test of whether or not the knife is ready for those final touches.

I was simply wondering if anyone had any idea as to why, with these two knives, I can achieve the blessed and holy state of shaving sharpness with the Tri-seps (~600 grit), but not with the Sharpmaker (~600 & ~1200 grit). I'm reaching the edge with both methods, and any difference in bevel angles is too small to be meaningful.

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Dave

Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon

 

[Cerilla]

Had the same problem when trying to reprofile with my sharpmaker. Ended up using 1/4" X 6" duct tape, and taping my round diamond rods into the hook sharpening groove on the stones, set it in the 30 degree slot, and sharpened away. Keeps the same angle, and is oh so much faster. Then finish with whatever stone and angle you desire.

 

[Joe Talmadge]

I'm not familiar with the GATCO system you mention, is it a lansky-style system?

The two possible explanations that spring to mind are:

1. With the spyderco, even though it's supposed to be easy to hold the bevel angle perfectly (after all, you're just holding the blade spine straight up and down), in practice it's not always that easy for people. If the Gatco system holds the angle perfectly (like the lansky and its ilk do), your variations on the spyderco could be causing some of the problem.

2. Again, perhaps you're using a slightly higher angle on the Gatco, so you're reaching more of the edge. The magic marker trick only tells you when you're getting really really close, but the only sure way to know you've reached the very edge is by the presence of the burr. Can you confirm to me that on the spyderco, you are raising a burr along the entire length of one side before switching to the other side and repeating, then alternating strokes to grind off the burr?

Joe

 

[dsvirsky]

Joe,
The Tri-seps is a little, 3", dog-bone style field sharpener. Definitely not a system of any kind; basically free hand sharpening.

With the GT Mini, I raised a burr on both sides, etc., just as you instruct in your FAQ. The knife was sharp, it just wouldn't shave.

With the Apogee, I worked on the Sharpmaker with alternating strokes, since I was really just expecting to do a touch up.

If anything, I'm using a lower angle with the Tri-seps: with the Sharpmaker, the scratches from the hone are only along the last millimeter or so of the bevel, while with the Tri-seps, I polish the entire bevel with each stroke.

Admittedly, I do sometines have some trouble keeping the knife spine exactly straight up and down, but I've managed to sharpen other knives back to shaving status with my Sharpmaker, when they were far more dull than these two ever were.

I appreciate your taking an interest. Thanks.

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Dave

Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon

 

[Tom Carey]

Do what I do with my Ralph. Do not hold the knife straight up and down. Angle it slightly. Practice and you will find just the rite angle. Mine shaves quite nicely. Took awhile for me to figure out just how much to cant it. Use the marker trick. It works really well.

Regards,

Tom Carey

 

[Cliff Stamp]

dsvirsky:

<font face="Verdana, Arial" size="2">Now I realize that blade geometry has a lot to do with whether or not a knife will shave</font>

The only thing that effects how well an edge will shave is the extent of the polish. Even very obtuse bevels like 45 degrees can be made shaving sharp

In regards to your sharpening problems, if the Sharpmaker is a little worn then you could be seeing problems because both those steels are very wear resistant and you need fresh ceramics to cut into them well. This makes the burr problem that Zut described even worse.

If you get the blades shaving sharp on the Gatco, and then give them a few strokes on the Sharpmaker will the blades stay the same, (which would indicate to me the Sharpmaker hones are worn), or do they blunt (in which case I would look at your technique with those blades, possibly the handle or blade shape is effecting your method).

The only other difference is that the Sharpmaker puts a lot more pressure on the edge due to its shape and you may be rippling the edges, however ATS-34 and 420V are very strong steels (assuming decent heat treats), so I can't see them deforming more than the other blades steels that you are not having a problem with.

-Cliff

 

[Jeff Clark]

As long as you are honing all the way to the edge and are at a reasonably low angle it should not matter if you maintain a perfect bevel. It sounds like you know what you are doing. I don't think these blades "like" the Sharpmaker rods.

I have run across this type of thing on occasions. Certain knives respond best to certain hones. I don't know why. Some like to be stropped and others don't. I think it has a lot to do with the grain structure of the steel, the size and hardness of the carbides, and the ductility of the alloy. Stainless alloys with a lot of chrome seem to be particularly opinionated.

In general I can get almost anything to shave with ceramic rods, but they don't always give me the best results. I think this is due to ceramic having trouble cleanly cutting ductile steel with a lot of chrome. I think the problem may be a microscopic burr of ductile steel that doesn't want to come off. The way that I handle this is to take a few light strokes at a high angle to cut off the burr.

My sequence is to hone with medium rods at 19-degree angles on alternate sides until the edge feels uniformly sharp (all of the following steps use strokes on alternating sides). Then I polish that bevel with a few strokes at 19-degrees on my extra-fine rods. At this point I try and remove any burr by adjusting my hand while I hone to about 35-degrees per side for 4 light strokes per side. Then I return to 19-degrees and do another light 8 strokes per side.

I expect honing to have left some flattening or dings in the edge as well as the burr. At this stage I do some light stropping on the edge using up-strokes against the extra-fine rods. Then I do some feathery-light down strokes at about a 25-degree angle.

Assume that you don't do all your work at the fixed rod angles. Assume that you have to fiddle around a little to lightly attack a microscopic burr right at the edge. I think you can get your razor edge. Your problem may be too much work done at exactly the same angle.

PS. Clean your rods with sink cleanser so that they cut more aggressively.



[This message has been edited by Jeff Clark (edited 01-23-2001).]

 

[dsvirsky]

<font face="Verdana, Arial" size="2">Originally posted by Cliff Stamp:
If you get the blades shaving sharp on the Gatco, and then give them a few strokes on the Sharpmaker will the blades stay the same, (which would indicate to me the Sharpmaker hones are worn), or do they blunt (in which case I would look at your technique with those blades, possibly the handle or blade shape is effecting your method).

-Cliff</font>

Well, I went back to the Sharpmaker with my Apogee, and gave it a few strokes with the medium hones . Didn't blunt, didn't stay the same -- got sharper! Now it's exactly where I want it: shaves (so I know it's sharp) and still with a slicing edge. Guess that'll be my technique with the Apogee in the future: start with the Tri-seps (kinda fun sitting there and stroking the edge back and forth across the rounded side), then switch to the Sharpmaker to finish.

Now the GT Mini just hates the Sharpmaker, so we'll stick with the Tri-seps there (besides, I no longer live in California, so I can't carry and use it openly anymore, anyway).

Thanks everyone.

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Dave

Let no one ever from henceforth say one word in any way countenancing war. It is dangerous even to speak of how here and there the individual may gain some hardship of soul by it. For war is hell, and those who institute it are criminals. Siegfried Loraine Sassoon

 

[Cliff Stamp]

dsvirsky:

<font face="Verdana, Arial" size="2">I went back to the Sharpmaker with my Apogee, and gave it a few strokes with the medium hones . Didn't blunt, didn't stay the same -- got sharper!</font>

So the Sharpmaker is basically acting like a smooth steel, aligning the edge indicating that it isn't removing much if any metal at all which is probably why you were not having much luck with it when the blade was blunt.

This could be due to wear on the Sharpmaker, or maybe dependent on the S90V itself. You could try another Sharpmaker if possible, or drop Ralph an email. Steve Harvey also has a couple of blades by Darrel Ralph in S90V so you might want to ask him about it as well.

-Cliff

[This message has been edited by Cliff Stamp (edited 01-24-2001).]