I got a ZT 550 in a few days ago, and it needed a sharpening so I decided to sharpen it up. I figured my DMT XC could do it, so I started. The issue I am running into is that I CAN NOT get a burr to raise. I have looked at the edge under magnification, felt it, used Sharpie, and everything says I am hitting the full edge. Still no burr, and I don't get it.
I even tried to convex it with some cushioned emery files because a V edge wasnt going to work. Still nothing. I also tried sandpaper on leather... Nothing.
Why will my damn edge just not raise a burr and not get sharp? This is beyond infuriating. At this point I am thinking about just spending all of my money and getting a powered sharpener (looking at the new KO Worksharp).
One thing is that is really wear resistant steel. It takes a LOT of work to reprofile and sharpen the first time. I was feeling the same way about my first S30V knife. Didn't think it would ever get sharp, even on my edge pro. I even contacted the guy @ EP and he told me to just keep working with the course stones. Since I was reprofiling it took me a total of a couple of hours over several days to raise the first burr.
The advantage of the S35V steel is that it is wear resistant. The disadvantage of the S35V steel is that it it wear resistant and takes a lot of effort to profile & sharpen.
Keep at it with your course stones, you will eventually get there.
Allen
S35VN is apparently supposed to be an evolution of S30V. Very high vanadium carbide content (and other carbides), just like S30V. I think Allen's comment above sums it up best. The extreme wear-resistance of the steel is likely most of the issue. Personally, I've never seen much of a burr or wire edge form on S30V when sharpening. And when it does, the tendency of the steel's carbides to 'fracture out' of the thinner edge means the little bit of burr that may be there will break away almost as fast as it forms.
I'd avoid the cushioned emery files (too soft) and also the wet/dry paper on this steel; the SiC/AlOx abrasive isn't as effective on the vanadium carbides. At most, during the heavy grinding attempts at this steel, neither of these options is likely helping you. More likely they're rounding off the edge somewhat, and possibly even scrubbing away whatever burr may otherwise be forming, if so.
S30V, for me, always responds best to diamond. I don't have any S35VN blades, but I'd bet they might be similar in this regard. I'd focus less on looking for a distinct burr, and instead pay close attention to how the edge is cutting, when periodically tested during sharpening. If the steel is going to form a burr at all, it's likely the diamond that will do it. But, as Allen mentioned, persistence is what it'll take. Make absolutely sure to check the edge every couple or three strokes on the hone, to be sure you're still progressing toward the apex, and not inadvertently rounding the edge or otherwise making it blunt/dull in the process.
Also, if your coarser diamond hones seem slow, it may be worth taking time to thoroughly clean them (Comet/Ajax & water, with scrub brush; Bar Keepers Friend & water works well also). Then, make sure to keep the hones wet while sharpening, so they don't get loaded up with swarf. I've grown to like using mineral oil on mine, and even mineral oil-based hand/skin lotion, for this reason (sounds odd, but it works well). Dish soap and water would also serve well.
David
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