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TOPIC: Question with a sebenza

Question with a sebenza 1 year 8 months ago #4098

  • Rlb
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I sharpened my micarta sebenza with s35vn the other day and ran into a problem with edge retention. I reprofiledthe edge at 18 degree per slide from 50 up to 0.6 microns. Whittled hair and sharp as a devils tongue haha, but then it stop slicing paper after like 10 cuts and it didn't really slice paper well. I was pretty surprised and have a few theories but wanted to see what people with the WE and a sebenza have experienced.

I don't want to do a convex edge but if that is the problem I could. Let me know if you guys have encountered the same problem and how you fixed it.

Thanks!!
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Re: Question with a sebenza 1 year 8 months ago #4100

  • BassLakeDan
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Rlb wrote:
..Let me know if you guys have encountered the same problem and how you fixed it. ..

Well Rib, looks like no one has had a crack at responding to you on this so i will give it a go... I wound up with 18deg per side a finish of 5u lapping paper after trying a zillioon stradigies. . I tried everything on the 35VN sebbie and this was the best I could do, as nothing much really works. The steel is not properly finished (in my humble opinion) at the Reeves shop... I have other S35VNs that I pocket EDC, for example a ZT0550, and it will take a -17deg with a finish of 0.3u (mirror) and even at that razor edge point sharpness it will out last the sebbie in EDC duty by 4x or better!

I am going to quote my neighbor, just up the road from Bass Lake, here in the Sierra Nevada Mountains, Mr Phil Wilson, who knows a thing or two about steel.. " The best obtainable tool steel in the world will make the worst very expensive custom knife if the heat treating is not right."

I recommend to anyone Phil's fine site at this link

Don't get me wrong, I love the Model 21 sebbie, carry it all the time, but the steel is just treated 'soft' and you will have to live with it or sell the knife.. Wish I had better news -Dan
Last Edit: 1 year 8 months ago by BassLakeDan.
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Re: Question with a sebenza 1 year 8 months ago #4103

  • cbwx34
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I can't speak to the steel quality, but an edge that fails after only a few paper slices means that it still has a burr. When converting a convex edge to a straight edge... it's tricky reaching the very edge... if for example, you mark it with a sharpie, it may look like it's all gone, but if you look at it under magnification, there can be the tiniest line still visible. There's a video that talks about this...



My suggestion would be to start from around the 400g stone, thru to whatever you want to finish at, and make sure that you have a good clean edge established. If it still fails, then you could add a small microbevel at a higher angle (I'd do it with the ceramics or finest stone you have), just a few very light alternating strokes to ensure the edge is burr free, and strengthen it a bit.

Clay also did a video sharpening a Sebenza (but he returned it to a convex shape)...



There seems to be a lot of "problem sharpening Sebenza" threads and videos... switching a convex to a flat grind usually causes this. It doesn't have anything to do with one grind being stronger or better than the other... it's just a matter of getting to the very edge.

Let us know how it goes!
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Re: Question with a sebenza 1 year 8 months ago #4104

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Thanks Dan, unfortunately this was one of my theories,I mean 58-59 RC is a little soft for me too. It's also why I didn't posted in on the CRK forum of the blade forums haha. Trust me a love CRK when it comes to quality but this isnt the first time I have experienced this so I thought I' d post it to see if I was just doing something incorrectly. Seems like you speak from experience...have you owned a s30v CRK heat treated to their standard 58 to 59? Any better?

I have heard of guys who will heat treat a sebenza blade but I am not sure I want to do that with all my CRKs. Maybe a convex edge will do better. I did it with um umnumzaan and it's held up a little better I think. .
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Re: Question with a sebenza 1 year 8 months ago #4105

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cbwx34 wrote:
I can't speak to the steel quality, but an edge that fails after only a few paper slices means that it still has a burr. When converting a convex edge to a straight edge... it's tricky reaching the very edge... if for example, you mark it with a sharpie, it may look like it's all gone, but if you look at it under magnification, there can be the tiniest line still visible. There's a video that talks about this...



My suggestion would be to start from around the 400g stone, thru to whatever you want to finish at, and make sure that you have a good clean edge established. If it still fails, then you could add a small microbevel at a higher angle (I'd do it with the ceramics or finest stone you have), just a few very light alternating strokes to ensure the edge is burr free, and strengthen it a bit.

Clay also did a video sharpening a Sebenza (but he returned it to a convex shape)...



There seems to be a lot of "problem sharpening Sebenza" threads and videos... switching a convex to a flat grind usually causes this. It doesn't have anything to do with one grind being stronger or better than the other... it's just a matter of getting to the very edge.

Let us know how it goes!

Thanks for the reply. Good thinking and I wish it was that easy. I don't want to say I am a master with the wicked edge but I feel comfortable enough with it to be pretty sure I have made and the smoothed out the burr. I do the sharpie trick and more so I trust my finger to feel when the burr has been created. This one had the factory convex edge Which was uneven and not consistent so in re profiling I had to be sure I got a burr along the whole blade and checked it more than I typically do while going through the progression. Thanks for the reply I appreciate the brainstorming.

Yeah I might try the convex edge next. I have seen the vid and no did it on my zaan which did a little better I think. Its m y next step. I wi ll keep everyone posted for future references.

Thanks!
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Re: Question with a sebenza 1 year 8 months ago #4106

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Cool. It sounds like you're confident you've reached the edge, but an edge that fails that fast is still a burr issue. I would still try making a couple of very light, edge leading, alternating strokes with the ceramics (if you have them) at a 3-4 deg. higher angle. You're not trying to create a microbevel... just enough to clean up the very edge... see if that helps.

If not, you can then go to Plan B. :-)
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