Shaving sharp Sebbie?...............

H

Hateman

Joined
Oct 28, 2000
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I have a Large Classic Sebenza. I've recently sharpened it with and Edge Pro at 21 degrees (going from Fine to Ultra-Fine) and finished off with the flats (UF rods) of a Sharpmaker. The knife is sharp but not shaving sharp, as I'd like my blades to be. The knife slces easily through a sheet of paper and slices a layer of skin, but does not shave hair. Does anyone have any suggestions on how to produce a 'hair poppin' shaving edge?
 
Sorry, I don't have any specific suggestions, but I have the same problem. I sharpened my small Sebenza on the Sharpmaker too, but the results were not overwhelming. I always get hair popping sharp results with my other knifes. Then I sharpened it with my Gatco sharpening system, and finished the procedure on the white rods of the Sharpmaker. Again I got the Sebenza sharp, but not shaving sharp. I only seem to be successful for 90 or 95%. I bought my Sebenza brand new and out of the box it was sharp, but certainly not as sharp as my other knives when they were new. I have no idea why I don't quite succeed in doing with the Sebenza what I can do with my other knives. :confused:
 
If you have maintained the same angle on all of your stones ending up with the ultra fine and are confident you havent gone too far with the ultra fines(you may want to go back to the fine until the maximum toothyness is acheived)-try this.

Take your ultra fine out of the jig and lay the blade on it and match it up to the angle previously sharpened on the blade then increase the angle(raise blade up a little more) and try a few strokes of this slightly increased angle
on each side and check sharpness.


Sounds like you are not removing the burr(or wire edge) on the blade with your sharpening method.

When you first try this it appears that incresasing the angle would dull the allready moderately sharp edge but believe me the opposite is true,you must remove the burr.

It may only take one stroke per side or as much as five.

If this doesent do the trick bring the knife up only with your fine stone to a nice toothy edge and the use the technique I described with the ultra fine,don't use your ultra fines in the jig at all.

After this step you could also strop the blade on a piece of fine leather .

In my experience the higher end stainless steels like 30V,440V,BG-42 ect are more apt to form a burr that needs to be removed.Simple stainless and carbon steels seldom form a difficult burr.

You might also want to invest in an ultra fine benchstone for this finishing process.The smaller DMT ultra fine diamond is great for this purpose.
 
I was in your shoes about four years ago. I tried everything I could, and the DMT Ultra fine sharpener worked best for me, (don't try it unless you can sharpen freehand.) I was able to get the hair cutting edge I wanted. Then a friend of mine suggested stropping it. So I bought the equipment and learned how to strop. Now I can get a polished edge on my sebbies that is scary. The hair on my arm pops up an inch or two when I touch it with the edge. It took a while to learn, and I would suggest learning on less expensive knives first, but IMHO it is the way to go. Now after a day of hard use and abuse, it only takes a few minutes to restore the edge to a hair popping polished edge. If I don't use it too hard, it just takes a few passes on the strop. I think it was well worth the time and money. Maybe it is something you should look into. Hope this helps.

Jason Hager

BTW, when I say hard use and abuse, I mean it. Both BG-42 and S30V hold a great edge.
 
If you can get a good magnifying glass or something like a 10X microscope to inspect the edge, you should be able to see the defect on the edge.

As recommended above it is probably a burr, it could also be that the sides of the edge have not been ground down all of the way to meet in a sharp V.

I can usually see a bur by looking closely at the blade at just the right angle of light, but a little magnification will make inspections of the edge easy.
 
Your problem may be as simple as your setting. I would not expect to get good shaving performance above 15 degrees. I would sharpen at 10 degrees then go back for a few light strokes at 15 degrees. Then I would lightly polish the edge at 15 degrees using the UF rods.
 
Jeff Clark said:
Your problem may be as simple as your setting. I would not expect to get good shaving performance above 15 degrees. I would sharpen at 10 degrees then go back for a few light strokes at 15 degrees. Then I would lightly polish the edge at 15 degrees using the UF rods.
Click to expand...

Problem is, with a thin grind like a 15 degree to a 10 degree, the edge doesn't hold up very well overtime for other cutting applications--cardboard, rope, etc. Thin edges tend to roll more on the high carbon stainlesses, too. S30V, now that I have used it for a few years, though pretty darn good, is just tough to resharpen. That burr edge keeps rolling back and forth. Leather strops work to a certain degree, but the leather can really take a beating. I've been rubbing green compound on a maple block, 3/4" wide, and using it as a strop. I like it better than the leather!

my .02 :)

Barry
 
Your bevels aren't meeting at the very edge. That's what sharpness is--the two bevels ending at the same point. The angle has nothing to do with it. Mark your edge with a marker, then give it a few strokes at the setting you've been using. That will show you where you have metal left to remove. What I do is use the EdgePro to sharpen a few degrees below the angle I'll be using the Sharpmaker, and then do touch ups with the Sharpmaker at the slightly steeper angle. This makes sure you are actually sharpening the edge, and not behind it.
Hope that helps.
 
I love this. A free exchange of ideas. Everyone has a different way to do it. I always learn something new here.
Thanks all.

Jason
 
Junkyard said:
I love this. A free exchange of ideas. Everyone has a different way to do it. I always learn something new here.
Thanks all.

Jason
Click to expand...

Junkyard is right, this is cool to read and learn from (a sticky for future Sebenzanistas?). I thank everyone for the information given here.

wire eddge, cmd: I saw the burr, after reading your posts, under a halogen light. It went the entire length of the edge. I attempted your first method and the results were partial. Nothing to do with eddge's advice, simply my lack of skills with such. I am trying to sharpen again with the Edge Pro using only the fine stones and will attempt to use the UF stone for any burr removal.

Junkyard, I've put off getting a strop and bench stones for some time. Any suggestions on where to get good afforadable, 'equipment' you mentioned such as a nice leather strop and anything I may need to keep that hair popping edge even after hard use?

Again, thanks for all the methods mentioned here; very informative. If anyone else has any ideas, please keep them coming. I'm finding out that no many how many knives I've sharpened, there's always more to learn.
 
Dont forget, the Sebenza is ground to be sahrpened on the Sharpmaker. I did what everyone eles did.. Bought one and practiced on my other knives until I got the hang of it. The hardest part is remembering the stroke count!
 
Be aware that although the magic marker trick works really well most of the time, it is not perfect. There are times when the marker is removed completely by the stones but the sides are still not meeting.

Something that looks like this \_/ can fool you when the sides are flat and at the same angle but do not meet.

Also, about the angles. Most knives will shave when profiled at 20 with a 15 back bevel like Sal recommends in the sharpmaker video. For me though, I keep all of my S30V and D2 sharpened to 15 and have had no problems with rolling or chipping when cutting tougher stuff.

There is a lot of "art" and a little bit of "science" to this, but mostly personal prefference from lots of practice.
 
Burrs form when you hone off a lot of material, particularly at low angles or when you work one side of the edge at a time. Often experts recommend that you work one side of the blade until you form a burr then work the other side. This is good advice for people who tend to hone too little and quit before they actually start to form an edge. Unfortunately this can be bad advice for more determined honers who remove more than the minimum amount needed to create an edge. These honers will get rather large burrs that will require extra attention to remove. One way to reduce burr formation is to always hone into the edge (aka hone "edge-forwards") sort of like you were trying to use your edge to shave your hone. If you work back-and-forth or hone edge-trailing (sort of like stropping) you pull the burr into line with your edge where it escapes abrassion. When you hone edge-forwards the burr gets pull into the junction between the edge and the hone where it gets more abrasion.

Once you have roughly sharpened your blade and create a burr you need to get rid of it. Only certain lucky combinations of steel, strops, abrassive compounds, and techniques will remove burrs via stropping. It is much more common for stropping to simply bend a weak burr into a flimsy state of allignment rather than removing the burr. If you apply too much pressure on your strop while trying to remove a burr you will round your edge.

It is most reliable to remove the burr via edge-forwards honing on a reasonably agressive hone. I like to use a fine diamond hone, but a medium fine aluminum oxide bench hone works well. If you created your edge by honing at 20 degrees per side remove burrs by very light edge-forwards honing strokes at 40 or 45 degrees per side. Only do about 5 to 10 light strokes per side (and alternate strokes left-side, right-side, left-side, right-side). You are sort of dulling the edge (making it more obtuse) at this point so you only want to do enough strokes to remove all trace of burr. After every few deburring strokes go back to your light and see if the burr is gone.

Once you have removed the burr, restore your edge by a minimal number of edge-forwards honing strokes back at your normal honing angle (say 20 degrees per side) using the same hone that you used for deburring.. By "minimal number" of strokes I mean about twice the number of strokes and the same amount of light pressure that you used in your deburring step. Do this while working left-side, right-side, left-side, right-side of the blade, don't work just one side at a time. Repeat this honing process with your finer hones. Don't go too far and create another burr. Keep using your light.

Once you have a fine, burr-free edge it may be ok to strop. I say "may be" since some stainless alloys don't seem to like stropping very much. Some of the harder stainless alloys seem to get duller if I strop them much, even with a very good edge to start with. I often do just a little stropping on plain leather with these alloys or none at all. Commonly I finish these with a few strokes on a ceramic rod v-style sharpening setup like a Spyderco Sharpmaker. I like the edge that I get from the ceramic better than I like the edge that I get on stainless when I strop. Plain carbon steels seem to always like strops, but stainless is much more uncertain.

Be careful how you strop or you will round your edge. Use light pressure and hold the blade at the same angle you honed at or maybe even a little closer to horizontal (a lower angle). Don't do too many strokes. Alternate left-side, right-side. At the end of each stroke flit the edge up and away from the hone. This looks kind of backwards from old movies of barbers stropping.
 
I decided to try the following after thinking about the Ritter mini-grip I brought back to a hairpopping edge on a Sharpmaker and the suggestions made here:
I used the Edge Pro to back bevel at 15 degrees and sharpened the edge at approximately 20 degrees (about 3 mm below the 21 degree line). I got a toothy edge just using the fine stone. I used the extra fine and ultra fine stones to do a light polish and smooth the edge a bit. Then, I used the Sharpmaker (40 degrees, fine rod flats only, 20 strokes) to finish. My Sebbie now shaves well and holds and edge that's quickly touched up on the Sharpmaker's rods at 40 degrees. I've hacked at boxes, plants and plastics; all receive clean cuts without any problems.

Thanks for all the help. BF knuts do it again :D
 
make sure you sharpen one side until a burr forms. this is especially important in the sebbie as they are sharpened to a convex edge. the convex edge magnifies the importance of making sure that you are actually sharpening the very edge. If you use the edgepro, you should have no trouble getting a shaving sharp edge with the medium stones...so long as the 2 bevels meet. good luck.
 
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