Please help with Sharpening...

R

razorhunter

Joined
Jan 27, 2002
Messages
470
I know you experts get tired of the sharpening questions, but I just can't seem to get it.
I am trying to hone my MOD Deiter 154cm on a 30 degree set up similar to the Sharpmaker 204. A.G. Russel to be exact.
I first attempted to reprofile it to 30 degrees ( 15+15).
I used a coarse rod until my hand was killing me and a wire edge formed. First problem was that the edge near the handle would roll over long before the curved part of the blade.
I finally got a wire edge over the entire blade and my hopes were high, but when I switched to the finer rods and then to the ceramic rods for a hone, it just wouldn't get a good hone like I know is possible. What in the heck is wrong? I realize everyone says practice, practice, practice, but what exactly more is there that I can do to "better" myself? Thanks so much for any help.
 
Buzzbait,
No, I didn't roll the edge on both sides.
I guess you are trying to tell me I should have. Could you please explain why it is necessary to do this on both sides?
 
Hmmmm... How to explain this...

By rolling the edge on one side, you've successfully gotten one side of the bevel to a 30 degree angle. You've also created a burr on the opposite side of the blade, which is the rolled over steel. A rolled over edge doesn't cut well, so you need to get rid of the burr.

By rolling over the edge on the opposite bevel, you will successfully get an apposing 30 degree angle to match the first side, and set yourself up for the real sharpening process.

After the second side is rolled over, you use subsequently finer hones, along with gentler sharpening pressure, to gradually shrink the size of the burr as you roll it from side to side. You will, at some point, get a nice clean edge with a very tiny burr. Strop off the tiny burr that’s left with a leather strop or rough cardboard box.

Did that make any sense, or am I rambling again... :rolleyes:
 
Actually, contrary to popular belief, its not.
I found this out about two weeks ago by accident.
I was sharpening an Old Timer lockback (440A) on a DMT benchstone. I started with strokes on the right side. After about fifteen strokes I had still not raised a burr. I figured that I was holding the blade too low and grinding edge too shallow. I remembered J.T.'s advise in the FAQs about how too keep an even edge on both sides of the blade, so I flipped it over and started grinding the left side. I raised a burr on the left side. Then I had to leave to go take care of some things, so I left the knife to finish later.
When I returned to finish the knife it was almost time for me to go to work, but I needed it to use in work. So I said the heck with the right side and just went directly to my fine ark.stone and a Veritas strop and compound.
When I was done, the edge was superb and shaved excellent.
I really don't know what to make of this. All I know is what happened to me.
Joe, feel free to respond. I'd like to get your thoughts on this.


Later,
Alex
 
Seems to me that it shouldn't be necessary to raise a burr on both sides to get a sharp edge -- if bevel "A" meets bevel "B" to form a triangle, then side B has to already meet side A without any further metal removal. Think about how one sharpens a chisel grind.

On the other hand, by raising a burr on both sides, you ensure that you've definitely achieved a state where the bevels meet. Plus, if you only raise the burr on one side, your angle isn't quite as acute as it could be and your edge will be slightly off center.
 
There is no need to grind a burr on both sides when sharpening, because noted in the above, once it has formed fully on one side the two bevels already meet. Thus all you need to do is remove it with a finer abrasive, just as you would with a chisel ground edge.

However, if you have ground one side of the bevel down to 15 degrees and the other is still at ~22, then you are not going to be able to sharpen it in a rig (Sharpmaker or whatever) unless the angle setting is greater than the side you have not reprofiled as otherwise you can never remove the burr that forms on the more acute side.

Note that there is a problem with this one sided burr formation grinding. If you repeat it over and over, always starting on the one side you will end up with a chisel ground edge. Therefore either alternate sides when sharpening, or start from different sides from time to time.

In regards to the burr forming at one area before the others, when you are honing you should attempt to keep the stone perpendicular to the edge. If you don't then you will be grinding at a much more acute angle near the parts of extreme curvature and thus it will take far longer to induce a burr formation along that region of the edge.

-Cliff
 
In regards to the burr forming at one area before the others, when you are honing you should attempt to keep the stone perpendicular to the edge. If you don't then you will be grinding at a much more acute angle near the parts of extreme curvature and thus it will take far longer to induce a burr formation along that region of the edge.
Click to expand...

Could someone please explain the above quote to me? I don't quite understand "keeping the stone perpendicular to the edge"
Thanks.
 
Again, hard to explain (grinning at Buzzbait),
I think what Cliff is trying to tell you is...

Your knife should be at 90° to the sharpening stone or stick. I think he is mostly refering the tip area...the part that is usually curved.

If you make a straight stroke at 90° along a stone, the curved parts, usually the tip, do not stay at 90° to the stone...because of the curve.

If you want to keep your edge at 90° to the stone, you have to rotate the blade to keep that angle. This means you have to 'sweep' your blade at the tip...to match the curve. This is also one of the things that makes a recurved blade difficult to sharpen.

Sharpening is an art, as you said...practice, practice, practice.

Hope this helps,



Steve-O
 
I'll also add that we are not talking about holding the knife at a 90 degree vertical angle to a bench stone. Think of it as pushing the blade directly along the stone, instead of making wide swiping motions. The more direct the push, the better.

Yes, you do have to use swiping motions on a SharpMaker, but you try to get as much downward motion as possible.

On a Lansky setup, this equates to pushing the hone as directly as possible into the blade.


Somebody needs to rev up their digital camcorder for this one. It's a real bitch to explain this in words. :mad:
 
Here is the deal, Cliff has it right on the head as for sharpening. I might add, that using a sharpie marker to blacken the edge and then about a 10x magnifier will quickly tell you if your getting all the way to the edge when sharpening. And it tells you how far you have to go if not. Also, I have a 204 sharpmaker, and I have sharpened freehand and on a lansky. With all of them its darn hard not to get some change of angle near the very tip of the knife. Hence a burr comes up at a different time there. Its also critical not to round the tip if your using a 204 setup. When using a 204 on the edges of the grey stones, I do not go all the way to the tip. YOu have to wait until using the flat and then the tip must not slip off the stone or lose contact with it as it will get rounded. In some ways unless you dulled your tip (I use the belly of the knife much more) its best to leave that last little bit go on the first few sharpenings, and let it stay factory. Real easy to round tips on the 204. Another fact, unless you have diamond stones, I like to stick as close to the factory angle as possible as its real hard to remove much metal. Some blade profiles are almost impossible for me to do right. I hate Tantos. Where the angles meet, its hard not to overlap into that sharp little triangle area.
 
Thanks guys, you've all been of a great help.

Buzzbait: I would love for someone to crank up the digital camcorder. That would be a hell of a show for us inexperienced. I guess I will wait for my Sharpmaker to come and study the instructions/video. I will also try to talk to the guys at the BLADE Show this year.
Now that tip of my knife is already slightly rounded from use, I'm gonna have a hell of a time trying to re-sharpen it.
 
razorhunter :

"keeping the stone perpendicular to the edge" (?)
Click to expand...

The following picture shows a rather extreme recurved blade and the arrows show the direction that the stone should be applied in order to get a constant angle along the edge. For a blade with a curvature this drastic, you pretty much are forced to work with a small hone section by section. However if the curvature is much slighter, then you can rotate the blade during the stroke so as to get the hone at the right angle to the blade, i.e. perpendicular.

http://www.physics.mun.ca/~sstamp/images/recurve_sharpening.gif

-Cliff
 
Lots of good information :)...thanks guys...


"Hunters seek what they [WANT].., Seekers hunt what they [NEED]"
 
Buzzbait,

Even a video and watching in person didn't help me , I still had to 'discover' it myself. Once you figure it out though, the little details like size of blade, types of steel and different sharpening media come as easy as pushing a peanut up Pikes Peak with your nose. :)

Keep practicing razorhunter!


Steve-O
 
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