Sharpening Questions? Burr formation with DMT, convex edges?

M

makey98

Joined
Jan 25, 2006
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Hello all, I am a newbie in this sharpening game and am having some trouble. I have a blue (325) grit DMT bench stone and the red (600 grit) and am having some trouble sharpening my folders. I am new to knives so I don't have anything special. My main EDC is a Spyderco Delica with Aus-6 steel and I can't make any progress with it. I tried everything from the black marker on the edge method and using two quarters as an angle guide. I can't ever get a burr to form. I don't ever notice a burr and can't figure out what to do. I can get the knife somewhat sharp but not to cut hairs or cut hanging paper. I read on this site how a burr formation may be difficult with DMT stones because they are agressive. Also, I read how burr formation may not be neccessary. What should I do? Practice more? Use a natural stone for easier burr formation. Use a finer grit? A steel or strop? I just want a sharp knife that I can maintain that can push cut very well.

Also, on another note, I am interested in convex edges and I am going to get a knife and use the mousepad method. Can you turn any blade into a convex edge? How would one go about it? Is it a good edge for stainless steels or more suited to tougher higher carbon steels??? thanks.. matt
 
In my personal experience, DMT stones don't tend to form much of a burr. My theory is that the diamonds cut very well and barely burnish at all; combine this with the light touch these stones require and your burr will be slight if present at all.

Of course, I have also found that the 600 grit DMT (fine, red) doesn't give me a very sharp edge until I give it a few passes on the XF (green, 1200 grit) stone (at which point a real killer edge comes out!); so perhaps I'm not the expert I wish I was :)
 
makey98 said:
I tried everything from the black marker on the edge method and using two quarters as an angle guide. I can't ever get a burr to form.
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Generally one of the bigger problems starting out is switching methods/techniques too rapidly. I would guess your biggest problem is simply honing at an angle which doesn't well match the edge on the knife.

One of most fool proof methods to sharpen is to lightly make a pass into the stone to flat the edge. Then with an x-coarse stone set the edge at 10 degrees, just approximate it. Stop honing when the flat has been removed.

Now make a few (2-4) passes per side at 15 degrees with a fine stone, then x-fine if desired. If this fails it is usually because of things like clogged stones, too much pressure, severely used knife, etc. .


Can you turn any blade into a convex edge? How would one go about it? Is it a good edge for stainless steels or more suited to tougher higher carbon steels?
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It is particular to steel or knife type. The easiest way is to use a belt sander above the platen as it will naturally make a convex. You can also arc the blade or the stone by hand or use a medium which has give like sandpaper on leather.

-Cliff
 
makey98 said:
I read on this site how a burr formation may be difficult with DMT stones because they are agressive.
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This is your problem.
Many people have also reported that when seeking to get a good burr on a knife, (The burr is key to gettin a knife sharp) that using a DMT stone will fail to make burr appear.
The 'bite" of a DMT stone is nasty agressive , best saved for when the knife is dinged or real,real dull.

All you need to do is get a normal stone, work until you get a burr, then get rid of the burr and then strop on leather with buffing compond on it.
Gets rid of the burr and makes the edge hair-poppin sharp!
 
Cliff, that is what I am asking. When I try the method you described the knife gets sharper, just not really sharp. And since I have no burr formation, I can't tell what I am doing wrong.

Allan, if what you say is true, what grit of stone should I use?

Thanks.
 
makey98 said:
Cliff, that is what I am asking. When I try the method you described the knife gets sharper, just not really sharp. And since I have no burr formation, I can't tell what I am doing wrong.
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So you applied a light flat to the edge and then sharpened until it was removed?

-Cliff
 
makey98 said:
Allan, if what you say is true, what grit of stone should I use?

Thanks.
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"if"?

Yes, what Im saying is true....LOL
As for the question of what type of stone to use?
Any stone will, or should be able to put a nice edge on a knife if you work the edge in the manner I have talked about,

However at some websites I have been reading, they tell about people who have tested one sharpening system against another have found that (Although all the sharpeners did a great job)...the very best was a Japanese water stone used first followed by a leather strop with buffing compond rubbed on it.

The Japanese waterstone cut steel very fast, and left the smallest burr hanging off the end on the blade.
And when you use a leather stope with buffing compond on it you get rid of even the smallest of burrs and scratches left over from the Japanese waterstone.

-----------------------------
That being said,,,,I dont want anyone to think that only water stones will work.

EVERYTHING WORKS!
The truth is that once you learn how to sharpen a knife, how to get and get rid of a burr (as talked about on some many websites that sell sharpeners), then any future sharpener you use will work better for you.

All the jigs, and the stones, all the power wheels, they all will seem to work better for you once you get down the basics.

How to I sharpen a knife?
I own a 10" long, Fine India Stone....(That was suggested to me by Ed Fowler)
I get a burr on the first side then flip
I get a burr on the 2nd side, then flip-stoke-flip
I can actually see the burr fall off, I always feel it fall off, then I switch to some sandpaper and sand off the marks from the stone.

At this point I used to switch to the buffer...but I have changed as of late.
The buffer with a set of two different wheels helped me get rid of all the scratches that might have been left over from the stone and sandpaper...

I still use the buffer a little to get rid of the scratches up higher on the sides of the blade, but for the actual edge I have switched to a home-made leather strop with green crome rubbed into it...
I place the leather flat on a board I have and glide my edge backwards across the leather.
It works like a charm,,,and is fast too!
 
Cliff, no I am just saying that I can never notice any difference in the metal like you guys are talking about. I never see a burr, but I do see the marker rub off so I know that I am sharpening at a good angle. When I have a dull knife I can hone and hone and hone and I can't really ever tell a difference in the blade itself. It feels sharper, then feel dull if I keep going, but I can't look at the blade and tell anything.
 
makey98 said:
I never see a burr, but I do see the marker rub off so I know that I am sharpening at a good angle.
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The marker will be removed before you are at the edge. This is why it is useful to put a flat on the edge before hand with 1-2 light passes right into the stone. This also removes all weakened metal along the edge. If the knife gets sharper and then dulls you are forming a burr. It is rare a burr is so large you see it by direct eye. You usually feel it, or check it under light or magnification.

-Cliff
 
I will try to make the knife dull (flat edge) before I start tonight and see how it goes. Maybe I should get a magnifier to see exactly what I am doing with each stroke to improve my technique. Any suggestions on type of magnifier/brand/?x ) Thanks again...
 
The flat is very light, you just barely see it by eye, just a few light passes into a fine stone. Radioshack has a nice 10X lighted magnifier for $10.

-Cliff
 
Well, I went to Radioshack and they had a little microscope thing that was lighted for 10 bucks, so I bought it, but then I was thinking about it and I may have bought the wrong one. This one has magnification 60-100x !! I just assumed (oops) that this was the right one......Too much mag? Thanks.
MAtt
 
makey98 said:
Well, I went to Radioshack and they had a little microscope thing that was lighted for 10 bucks, so I bought it, but then I was thinking about it and I may have bought the wrong one. This one has magnification 60-100x !! I just assumed (oops) that this was the right one......Too much mag? Thanks.
MAtt
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That will work just fine, Matt; I'm guessing Cliff meant 100x in his post. I usually examine edges at 40x or greater, at 60-100x you'll easily be able see what's going on as you sharpen.
 
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