Sebenza Won't Cut

Razor

Razor

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Dec 8, 1999
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I cannot get my large classic to cut like the spyderco military, that I use to own. Is it because the spyderco was flat ground? The spyderco was S30V. It also seem to stay sharper longer. All I own now is sebenzas, and I think they are the best knife made. I have sharpened the classic on a diamond stone, and a spyderco ceramic stone. I cannot figure why the military cut so much better. Any thoughts?:confused:
 
Most likely a thinner grind. Most Spydercos are ground at 15 degrees per side. IIRC, Sebenzas are ground at 20-22 degrees per side.
 
I agree about the thinner grind. You can reprofile your edge to 15 degrees but it would take a long while on the sharpmaker.
 
Razor, I understand you situation. I would like my sebenzas to cut like a Caly ZDP-189. I also agree it's the edge bevel. I took a diamond system to try and bring the bevels down to about 17. It's a lot of work. It helped, but I suck at sharpening. My suggestion it to try that, or send it back to CRK with a note to bring the edge bevels down.
 
Reprofiling with diamonds is not that bad. Do it while you're in front of the boob tube, the time will pass before you know it. Just check the edge frequently to make sure you are grinding it the way you want. You will also probably end up with a serious burr that will take some care to properly remove.

The more acute edge not only cuts better (less resistance) but it holds its edge longer. With a good steel with good heat treat you could take the edge down even farther than 15 degrees per side and not worry about it unless you are truly abusive with your knives. If you are, you could still keep the angle down if you put a convex edge on it.

Buck published some data a few years ago that showed a medium grade steel outperforming a premium steel in the CATRA tests, and the only difference in the blades was the edge angle (30 degrees and 40 degrees, respectively, total included angle).
 
Razor said:
I cannot get my large classic to cut like the spyderco military, that I use to own. Is it because the spyderco was flat ground? The spyderco was S30V. It also seem to stay sharper longer. All I own now is sebenzas, and I think they are the best knife made. I have sharpened the classic on a diamond stone, and a spyderco ceramic stone. I cannot figure why the military cut so much better. Any thoughts?:confused:
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Send it back for replacement with one that is properly made and can cut.
 
I don't believe it's that simple. CRK makes them how they think they should be made, and without instruction of what you want, you won't get anything different.
 
You also might want to try stropping the the blade on a leather belt. I did that on my LE and the edge went from ho hum to blistering sharp.;)
 
DGG said:
Send it back for replacement with one that is properly made and can cut.
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The knife is properly made. Like DaveH said, CRK has standards that they have been using for ~22 years. They know what they're doing. Apparentally the edge is just not up to his expectations.

Scott Dog said:
You also might want to try stropping the the blade on a leather belt. I did that on my LE and the edge went from ho hum to blistering sharp.
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Did you use any kind of compound? How exactly did you use the leather belt? Rough or smooth side? Are you sure there wasn't a burr to begin with, and you just removed it by stropping? Sorry for all the questions :p
 
I had similar problems with my small Sebenza, and i tried the Sharpmaker but i could not get it scary sharp.
Also with the leather wheel on my Tormek, i got a polished edge, but no scary sharpness.
I finally found what i think to be a possible answer, as i now have a Sebbie that can cut freestanding hair on my hand with the complete edge, and can whittle hair with the straight part of the edge, just like my Spyderco Jess Horn ZDP.
For this, i just use one white stick from the Sharpmaker as a sharpening steel in my hand, and give the Sebbie very light passes on the transition from flat to corner.
You might want to check that Sharpmaker stick first for chips on it's corners, as these do occur sometimes.
Don't use any pressure while stroking, glide the steel over the stick, and just let the alumina ceramic do it's work.
Now and then pull the edge over a piece of medium hardness wood to remove any burrs and continue the stroking process until you are satisfied.
Take care though to follow the edge of the knife, as there is a smooth angle transition between the straight part of the edge and the curved part, from about 15 degrees per side to 22.5 degrees per side near the point on mine.
You can use the black feltmarker trick if you want, but you can also hear it.
:)
 
I used the diamond rods on the Sharpmaker to thin mine down to 15 degrees per side. I use the ultrafine stones at 20 degrees per side and then a leather strop loaded with chromium oxide to finish. Having done all this, I think it now passes as scary sharp.

Still, it would already split hairs with the original bevel. It just slices better now.

I know everyone seems to think flat ground is magic but unless you're slicing something fairly solid that's thicker than your blade is wide I think hollow ground is better. YMMV.
 
kwackster said:
I had similar problems with my small Sebenza, and i tried the Sharpmaker but i could not get it scary sharp.
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Like I said, most Sebenzas are sharpened at a more obtuse angle than the Sharpmaker can handle. So when you were trying to sharpen it, you were only hitting the shoulders of the edge.
 
DJang:

I used an old brown dress belt about 1 1/2 inches wide. I turn it rough side up and over my mousepad on my desk. I loaded it with Simichrome. I just stropp lightly for as long as feel like and then wipe down the blade. It's working well for me so far. And no I'm not sure if I just knocked off a burr. I just figured if I did that every so often it would keep the edge in top shape and I wouldn't have to use my edge-pro on it.:eek: :p
 
I had the same experience when I first rec'd my Sebenza - great fit and finish, not a great cutter.

I reprofiled it in steps trying to achieve the performance I was used to - eventually exceeding the ability of the standard heat treat (mine measured 58RC ) to suppport the edge.

3rd party re-heat treat and more re-profiling - it's now a cutting machine and has the fit and finish CRK built it's reputation on.

I can send you a picture or two of it - might give you an idea of what the blade will look like once you start slicing the meat off it. If you're careful and have a technique to maintain consistant bevels, it will look good. I think I went all the way to 10 deg (primary) per side before engaging the entire tip with the stone - might want to check that number in my prev post listing before grinding you're own blade.

Mine stands at 6.7 deg per side primary, 12.3 deg secondary (measured). I stopped using it in the hedge and garden for touch-ups because it left polished-face spikes on all the cut lines. Watch your fingers!

MAT
 
I agree with most of the replies here, it's the angles.

On mine, I used a diamond stone to reprofile my small classic sebbie to 30 degrees total (15 per side). Then a few passes on the courser then finer Sharpmaker stones, mostly to polish the 30 degree sides for looks.

Then used the course sharpmaker stones to put a 40 degree (20 per side) final edge on. Went through those course, then the fine, then ultra-fine stones. Finally, did about 50 passes or so per side on a leather strop, and it's dang sharp now.
 
I'm glad we're discussing this out in the open. I'll be send a knife back soon, one that needs a refurb, and I'll ask for a 15 degree edge per side.
 
I might need to do that as well. My premier knife should also be my favorite cutter.
 
I got tired of that convex edge, couldn’t get it sharp, so I put tape all over the blade sides and handle to protect it, and took a coarse, large stone to those blasted shoulders. I eye-balled it, very carefully. It didn’t take that long. Went to a medium stone to remove the scratches. Finished it off with fine sticks, and voila - supersharp. I was so happy that I had finally done it. Looks good under a magnifying lens too. It helps if you’ve had lots of practice over the years on lesser knives.
 
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