ONLY....diamond....will cut my Fallkniven U2

L

Lavan

Joined
Nov 8, 2000
Messages
2,301
That SGPS just ....laughs.... at my Sharpmaker. It will leave "color" on the sharpmaker and I suppose 20 or 30 thousand strokes would take off a burr, but to get it "shaving sharp" I have to use diamond.

Either eZe-Lap or a DMT perforated "stone." (stone works best, but the lap will work for a quickie)

:)
 
Lavan said:
That SGPS just ....laughs.... at my Sharpmaker.
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A 62 HRC steel is butter softer compared to the Sharpmaker ceramics. I just re-edged a U2 last night on the Sharpmaker. The Sharpmaker has no problem with full hard, very high wear resistant steels like CPM-10 at 62.5 HRC, M2 at 65 HRC, etc. .

-Cliff
 
Ceramic is nearly as hard as diamond and both are significantly harder than steel so both should work well to do an edge reprofile or simple touch up on any blade regardless of the Rc hardness. You may be taking steel off of the wrong place on the blade by sharpening at an incorrect angle that doesn't affect the cutting edge when you use the Sharpmaker.
 
Well, I used it like I do on all my other knives. First the shallow angle, then the 40 degree finish. It was sharp. Just SLID though paper. But ...shave? No way. Arm hair intact. And it didn't....feel...sharp. Even though it was. But a little freehand on the diamond stone and it feels (sorry Fallkniven) SPYDERCO sharp.

:confused:
 
Personally I prefer the diamond free hand method also but I strop it after to remove the wire edge. Next time turn the blade around and see if it shaves that way. In other words if it doesn't pop hairs off in your right hand going down your left arm try it with your left hand going down your right.

Not sure of the technical term but that is the wire edge moving from one side to the other when you sharpen. Stropping will center it and remove the wire. If stropping isn't available just cut some soft pine or sharpen a pencil or two with it and then see if it isn't better after the wire gets knocked off a bit.
 
Probably because he's using a diamond sharpener that's a bit coarser than the ceramics, thereby leaving a slightly toothier edge which feels sharper, but really isn't

John
 
GarageBoy said:
If ceramic is as hard as diamond, why does it cut slower?
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It's not as hard as, but just in the same league.

What's important is that both are significantly harder than steel.
 
GarageBoy said:
the diamond gave it some bite?

If ceramic is as hard as diamond, why does it cut slower?
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I don't have a Spyderco shapener but I susupect its because the 'grit' is finer. 600 and 2000 Wet and Dry is the same stuff, only the coarseness is different.
 
I've sharpened my Chris Reeve Nkonka in 3-V with the Sharpmaker. That's about as tough and hard as steel gets in knives.
 
GarageBoy said:
If ceramic is as hard as diamond, why does it cut slower?
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It isn't as hard as diamond, it is mushy soft compared to diamond. Even cubic bornn nitride is only half as hard as diamond (knoop), diamond stones will readily cut into ceramic ones.

That being said, a coarse ceramic stone will readily out cut a diamond one, and a waterstone of similar grit will cut faster than both of them. There is more to sharpening speed than just hardness of the abrasive.

Lavan said:
But a little freehand on the diamond stone
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You could simply be seeing the effect of a different angle, or the edge just needed more work to finish it off.

-Cliff
 
Certainly all are possibilities.

STR..... I always do the alternate shave thingie with every knife I sharpen. Gotta be EVEN if I'm gonna do a decent job on salami.

I....have....(I think) done it on the Sharpmaker. Maybe the impressive part is how much quicker it is on the diamond.

:confused:
 
Lavan said:
Well, I used it like I do on all my other knives. First the shallow angle, then the 40 degree finish. :confused:
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BUZZZZZZZZZZZZZZZZZZZZ!!!!!!!!!! All knives are different. If you have a knife that already has about a 30 degree bevel with a 40 degree edge, then it will be a snap on the Sharpmaker. If your U2 has a 50 degree bevel and possibly something like a 55-60 degree edge (or even a 50 degree edge) you will have a lot of work to do on the Sharpmaker to reprofile the blade to the point where you are actually hitting the edge and sharpening it.

The Sharpmaker will get it there, but the medium rods aren't very corse and take a long time to get anywhere, especially with a harder steel. Reprofile with a corser stone (diamond, ceramic, aluminum oxide) or sandpaper. Get approx. a 30 degree bevel on it and then put a 40 degree edge on with the Sharpmaker.
 
GarageBoy said:
the diamond gave it some bite?

If ceramic is as hard as diamond, why does it cut slower?
Click to expand...

It's all about the grit. My extra coarse and coarse aluminum oxide EdgePro stones eat super steels for breakfast. M2, D2, s30v is no match.

However, if I slapped on the ultra fine (600 grit) EdgePro stone I'd be reprofiling all day long, like I would be with the Sharpmaker's grey rods.

Spyderco offers the diamond rods for the Sharpmaker. I wonder if they could offer a coarser ceramic option, or aluminum oxide. I have a feeling if they offered a coarse aluminum oxide set of rods they would wear down very quickly and be useless in no time.

This is why aluminum oxide and other water stones work so well, as they wear down the "teeth" break off exposing fresh teeth.
 
jmxcpter said:
Probably because he's using a diamond sharpener that's a bit coarser than the ceramics, thereby leaving a slightly toothier edge which feels sharper, but really isn't

John
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Exactly, I sharpen my U2 with my Fällkniven DC4 whetstone using the ceramic part last.
 
It WASN'T ....really.... sharp. Paper just sorta...tore. An it musta been PULLING hairs out.

ANYHOW...... I went back to the Sharpmaker and took....some TIME.... and.. Presto. Sharp. Paper like laser and hair pops off.

Now it's ....right.

:)
 
WadeF said:
I have a feeling if they offered a coarse aluminum oxide set of rods they would wear down very quickly and be useless in no time.
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Solid Aluminum Oxide rods would just snap off, you could coat it around a core, but you would wear it off just working one one knife. just wrap sandpaper around the existing rods, or lean a stone against them. Or simply do profling free hand as you don't need precision angles for that anyway.

-Cliff
 
G'day fellas. I'm new to your forum (although I've been over at swamprat for a while)
I love my 204 and anyone who indicates that they use knives in their work or hobby when the walk in to the camping shop I work at, gets a demonstration, (we sell heaps).
I do dozens of demos a week and the only troubles I have seen are with some very hard blades Cold steel sanmai and A kershaw kitchen knife, some very steep angles on the primary edge( the rods don't contact the cutting edge) , or a dirty ceramic rod ( they just don't work if the're dirty.
Somtimes if a blade is real steep or blunt I'll use a diamond plate to re-profile The 204 will do it but sometimes I'm short of time. and the (coarse) diamonds do cut faster. My biggest problem with Diamond plates is the diamonds break out and the plate looses it cutting agressivness, and consequently they need to be replaced. Ceramic rods/"stones" shouldn't wear out with domestic use. But they are a little slower. Hope that helps Carl
 
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