shave hair but not slice newsprint?

C

candlelight001

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Jun 3, 2008
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I have a new Koster Mini-Nessmuk that I've been sharpening this afternoon. It now shaves hair, but struggles to cut newsprint. Once it's slicing it's good, but it won't pushcut it. And it shaves better than my ML Kephart (my sharpest knife), but cuts rawhide worse.

It's a flat grind with v-bevel, 12C27 stainless.

What gives?
 
don't nessmuks have rather thick blades ... i'm sure that could factor in in some way plus from my experience with my work knives a "toothier" edge will slice better while a more polished edge will push cut better i can't really speak completely for you knife but knowing the little i do about edge geometry and finish ill offer what i can
 
candlelight001 said:
I have a new Koster Mini-Nessmuk that I've been sharpening this afternoon. It now shaves hair, but struggles to cut newsprint. Once it's slicing it's good, but it won't pushcut it. And it shaves better than my ML Kephart (my sharpest knife), but cuts rawhide worse.

It's a flat grind with v-bevel, 12C27 stainless.

What gives?
Click to expand...

I've had similar experience. Have you stropped from both directions? Suspect you still have a burr - try shaving with blade turned over to the other side and if it catches it's still got a burr
 
antonio_luiz said:
I've had similar experience. Have you stropped from both directions? Suspect you still have a burr - try shaving with blade turned over to the other side and if it catches it's still got a burr
Click to expand...

I second that.
A little trick an old timer showed me is to take a piece of card board (I use the stiff kind that is on the back of a legal pad) and rub white jewellers rouge on it. Put it on a hard backing like a wood board and pull the knife at the degree of angle of the edge. Pull the spine toward you and do this equal times on both sides.
The edge needs to already be as sharp as you can get it. This only takes the burrs off and polishes the edge to final perfection. You will have an edge that will cut right through new paper with out snagging. On very thin knives like fillet knives it will split a hair.
 
Freehand the whole way with a DMT coarse, DMT fine, Spyderco medium stick, Spyderco white stick. If there's a burr, how do I tell what side it's on, can't feel it with my finger.
 
candlelight001 said:
Freehand the whole way with a DMT coarse, DMT fine, Spyderco medium stick, Spyderco white stick. If there's a burr, how do I tell what side it's on, can't feel it with my finger.
Click to expand...

With due respect, it sounds as if you just haven't got it sharp enough yet for it to perform as you wish.

Are you sure about the angle you're using?
 
pushcutting newsprint is harder than shaving arm hair, no biggie, just work the finer grits more.
 
rifon2 said:
With due respect, it sounds as if you just haven't got it sharp enough yet for it to perform as you wish.

Are you sure about the angle you're using?
Click to expand...

Entirely possible... :thumbup: Just following original angle, using the sharpie pretty often, grinding it off, then marking it up again. How long should I go w/ finer grits before deciding I'm doing something wrong?
 
candlelight001 said:
Entirely possible... :thumbup: Just following original angle, using the sharpie pretty often, grinding it off, then marking it up again. How long should I go w/ finer grits before deciding I'm doing something wrong?
Click to expand...

It's hard to say without having the knife in front of me & feeling how it cuts.

But what I'd recommend is to skip the Spyderco medium hone after using the DMT fine hone.
Go directly from the DMT fine to the Spyderco fine, then to a strop.

In my experience, it's very difficult to get a blade to push cut newsprint without stropping it properly.
Someone already mentioned using white compound on a cardboard strop - I haven't tried that.
My preference is green compound on a leather strop.
 
Sometimes when I'm having trouble with newsprint, I try the knife on heavier paper like 20 lb printer paper just to see if I'm close or totally muked up.
 
Just wondering, what do you use your knife for? I used to make sure that my every day knife could cut cigarette papers and shave hair, but after a time I realised that what I really needed was a knife to strip armoured cable , open boxes and sharpen the odd pencil! Since then I don't spend half as much time sharpening, and as a result my blades lasts longer. When I do sharpen it, which is generally a few strokes with a steel, I'll get it to shaving sharp with a toothy edge. This gives me a good enough edge for what I need, but not necessarily one which will perform push cuts on thin paper.Sharpen it to perform best on the material you cut most.

Regards, Ian
 
candlelight001 said:
Freehand the whole way with a DMT coarse, DMT fine, Spyderco medium stick, Spyderco white stick. If there's a burr, how do I tell what side it's on, can't feel it with my finger.
Click to expand...


After finishing with the medium ceramic you most likely have a good sharp edge that cuts well but after you are finished with the white stones it either feels, sharp in spots, dull the whole way, sharp the whole way but cuts bad or shaves to one side and not the other. These are all examples of what a burr can cause, to check for the burr rest the edge at the bevel angle on your thumb nail and with a stropping (edge trailing) motion feel the edge on both sides. If a burr is present is will scrape the surface of your nail and if not it will feel smooth.

Your sharpening method is good but you might want to try the ceramic benchstones and add the UF ceramic to the mix. With the benchstones you can use more preasure making them work faster and more effectively just remember to finish with light strokes it helps to lessen the burr. To properly remove the burr you will need to finish with a strop loaded with abrasive, most commonly a good peice of leather or if you want to test you angle holding skills a peice of MDF.

P.S. The sharpie is a good trick but don't forget to watch your scratch pattern.
 
OK, now I'm frustrated... took y'all's excellent advice, decided there was a burr, looked closely at edge and realized one side was a steeper angle then the other, with burr on steep.

Used coarse DMT to grind steep side till it was roughly even with the other. Then set up the sharpmaker with grey stones, 20 or so passes, now I'm cutting magazine paper.

So of course I think, "why not sharpen some more" 20 more passes, now I can't cut jack. I assume I have another burr. Or the same one.

What is the nature of these burrs? Can you take one off, only to put one back on in a few passes? Are they stubborn and really never go away?
 
candlelight001 said:
Used coarse DMT to grind steep side till it was roughly even with the other. Then set up the sharpmaker with grey stones, 20 or so passes, now I'm cutting magazine paper.

So of course I think, "why not sharpen some more" 20 more passes, now I can't cut jack.
Click to expand...

What did you use to do the "20 more passes"?
 
candlelight001 said:
Freehand the whole way with a DMT coarse, DMT fine, Spyderco medium stick, Spyderco white stick. If there's a burr, how do I tell what side it's on, can't feel it with my finger.
Click to expand...

That doesn't sound bad. I've used the Spyderco gray and white stones for years... finish it up with a strop and you should get there... that's the only other thing I used to use in conjunction with the spyrderco stones. I never bothered with the Spyderco Ultra Fine white as it just didn't seem to make any different in my edge. A Strop with some diamond paste, or even flitz or simichrome will take your edge to that next level of sharpness.

But stropping has always been to key for me in a really razor sharp edge. The stones will get it close... but the strop makes all the difference.
 
candlelight001 said:
OK, now I'm frustrated... took y'all's excellent advice, decided there was a burr, looked closely at edge and realized one side was a steeper angle then the other, with burr on steep.

Used coarse DMT to grind steep side till it was roughly even with the other. Then set up the sharpmaker with grey stones, 20 or so passes, now I'm cutting magazine paper.

So of course I think, "why not sharpen some more" 20 more passes, now I can't cut jack. I assume I have another burr. Or the same one.

What is the nature of these burrs? Can you take one off, only to put one back on in a few passes? Are they stubborn and really never go away?
Click to expand...


The burr is the result of your bevel coming together, once the two bevels meet the excess metal is rolled over to one side thus resulting in a burr. In the last few passes down the stone use light preasure to aid in reducing the burr. The ONLY stone I have seen that will remove a burr(or come darn close) is the Spyderco UF ceramic and the finner DMT's, burr's can be VERY stubborn and if you don't use a really fine stone there almost impossible to get rid of. To help better understand what is happening use a high power magnifying glass or one of these are very helpfull.

http://www.opticsplanet.net/carson-digital-microscope-camera-epix.html
 
Get a loupe or magnifying glass, and verify that you have sharpened to the edge. When I'm putting on a new edge, the angle almost always gets reduced a bit, it is easy to get almost all of the bevel sharpened but still have a tiny line of unsharpened steel right at the edge. Just a possibility...
 
Broos said:
Get a loupe or magnifying glass, and verify that you have sharpened to the edge. When I'm putting on a new edge, the angle almost always gets reduced a bit, it is easy to get almost all of the bevel sharpened but still have a tiny line of unsharpened steel right at the edge. Just a possibility...
Click to expand...


I hate when that happens :mad:
 
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