CPM S110V

Legacy Forum Archive advanced-techniques-and-sharpening-strategies
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[quote quote=40692]

Tom, have you devised a way to monitor whether or not you have effectively removed the serrations from the previous grit, or do you have to resort to just counting the strokes? I imagine that examination with a microscope would be useful, but without measurement software and high magnification capabilities, I don’t know how one would be able to know that they have effectively replaced the previous grit serrations. [/quote]
I'm not normally that obsessed with getting a perfect edge, so I just double or triple the number of strokes I would otherwise use if I want a really, really sharp edge. I normally keep my USB 'scope set to the lower magnification (about 55X), so it doesn't give me the image I'd need to evaluate the roughness of the edge. I proceed knowing that the increased number of strokes will have some payback.
It's interesting to consider that a mirror-like set of bevels will not automatically give you an optimal edge, but working toward the optimal edge will produce a mirror-like bevel. Huh!
22

I have been looking into S110V for a chef knife and have learned that the Heat Treating is the most important aspect after having a “clean” steel from your source. The interesting thing is that most custom knifemakers hold their HT process like it is some sort of proprietary process. There are plenty of shortcuts which could be done especially in the cryo process (temps, vacuum, rates, dwells, # cycles, etc). All of these affect the edge. It is no surprise to me that different knifemakers will have different edge performances with the same material.

It is interesting that “we” the sharpeners are probably the best testers of the knife edge. I think that edge performance characteristics during the sharpening process would correlate to edge performance characteristics during use. There are of course many variables to each which would preclude direct correlation and consistency but I think the same trends would correlate.

Knives need professional HT which requires expensive equipment and defined/documented processes. Peters Heat Treatment in Berlin, PA is one of the best and will HT a knife with the same equip/processes as they use for Aerospace landing gear. I will not buy a knife from a custom maker unless they are transparent in their HT process. BTW, an 8 inch chef knife in S110V costs over $1200 and a maker who says trust me will not get my business.

23

Finally was able to revisit the Spyderco Manix 2 S110V blade. After receiving the 800/1000 chosera stones, I tried to back up and see what they would do ( I finished with the 10K chosera last go round) while keeping the same 18 deg angle. I was not successful.[attachment file=“800k.bf2.jpg”]

From there, I went back to the 1500 diamond confirming the scratches were consistent from shoulder to apex and verifying a burr before moving on.

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1500.diamond.jpg
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From here, my progression was 800/1000/2000/3000/5000/10,000 chosera. Scrubbing first then edge leading, per forum recommendation, with very light pressure until each grit had scratch uniformity. Finally, light stropping at 16 deg with both 1 micron and 0.5 micron leather strops.

Again, this blade is sharp but not where near where I would expect it to be. I do not believe it is my technique as I followed this with a Shun VG10 blade using both diamond and chosera to 10k and it is screaming sharp! I know the S110V steel is supposed to be difficult to sharpen but I am at a loss… I have ordered a set of DLF from 6 to 0.1 micron and will try them when they arrive. I can’t imagine that the DLF will solve my issue but don’t know what else to try.

24

Rich, just a dumb question first…Please clarify how your photos are oriented so I’m clear on what I’m looking at. Are they posted “bevel down?” If that’s the case, for less confusion you may be able to change a setting in your soft to rotated the view 180º so the bevel is up to coincide with knife clamped orientation.

To help your issue, I suggest, just for kicks, repeat your Chosera’s 5K then 10K. Feel the apex when doing the alternating side, bilateral, edge leading strokes to make sure your edge feels very sharp.

First, what type of strop are you using? I assume you’re using the basic cow leather WE strops. But we both know what assume means, LOL.

Try to lower your angle for Stropping, 3º, per side to 15º and then do your alternating, bilateral, edge trailing strops. Please let us know the results. If this doesn’t help you might also try to lower the strop angle only 1º to 17°, after again going back to the 5K and 10K Chosera’s. These little technique changes may help you narrow down your technique issue.

From viewing the photos your bevels look pristine. Like they were done by a machine, they’re so straight and even and parallel. Really good work there.

25

I think you may be battling the Niobium carbides in the S110V vs the Vanadium in VG10. Niobium carbides are much harder. The chosera stones may not be hard enough and you could be just abrading the steel matrix “around” the carbide and messing up your apex. You prob can only see it with an electron scope (on my list - LOL).

Try not using the chosera at all and see how far the diamonds will take it. Maybe use diamond emulsions on cardboard at the finest level. Zknives.com and knifeinformer.com have great info on S110V basically calling it THE HARDEST to sharpen and sometimes heat treated to 64 RC.

26

The photos are taken apex down. Marc, I will try your suggestion of repeating the chosera 5/10k. I believe the edge felt very sharp when finishing with them. I will experiment with strops at 15 deg and 17 deg. The strops I am using are cow leather (not WEPS as I just replaced them with leather form Oldawan) Yes, ASSUME (ASS out of U and ME). Thank you for the kind words, I am really paying attention to the details!!

Readheads, your suggestion is were I was headed. I am skeptical of the chosera stones use on S110V. I have ordered diamond lapping films and will try when they arrive (after trying Marc’s suggestions above). Talk to me about diamond emulsions on cardboard. This is just another form of stropping? Why cardboard and not a traditional strop media?

This leads me to another question. When talking sprays & emulsions, what are the differences between CBN spray/emulsion, poly diamond emulsion, boron carbide emulsion, etc. Is one better than another or just different? Reasons for using one over another?

Lastly, has anyone used chosera stones with S110V, CPM S90V, ZDP-189, ? If so, what was your experience? I really enjoy the feel these stones provide during the sharpening process. I am trying to understand if there are applications where they should not be used.

 

27

Rich, I have no experience in using cardboard (some others herein have talked about it though). I suppose it is just a part of the quest to find a nice stiff medium to hold the emulsions, etc while you “impact” the bevel. The various emulsions confuse me also and it would be a major science experiment to determine which works best on which medium for which steels.

Ah but the quest for knowledge can be a stimulating experience. LOL - fun posts you all; I will be active on these posts as I hang on the Jersey shore for 2 week even though I left my WEPS home.

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I’ve tried hardwood and brass as mediums, and they both work, using paste. The brass seems to require a lot of effort and a lot of paste to get it fully loaded with embedded diamond particles, so I didn’t go down that path. I haven’t tried (cereal box) cardboard, but it seems to me to be a good application. Easy to replace, too.

29

Rich, how many different steels or different knives have you sharpened so far with this same Wicked Edge System? Have you been able to sharpen those knives to a sharpness of your liking?

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Yes I have. Many various kitchen knives, ZT folders, Kershaw folders and spyderco folders. No others using S110V though.

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Did you sharpen these knives with you’re current setup to a sharpness of your liking?

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Yes I did. All of the other knives I have sharpened turned out great!

I had a conversation with Ken Schwartz today. His opinion is that the vanadium content being so high, the chosera stones are not able to erode these steel nuggets. His recommendation was two fold,

  1. Add a small amount of cbn (WATER BASED ONLY) of the same micron size to the chosera stone surface. This will help to produce more slurry by eroding the chosera more rapidly while adding diamond particles to the slurry taking care of the vanadium in the steel.
  2. Nubatama Platinum stones. It was explained that these stones will take care of these harder steels where the chosera fall short. I'm considering 1500/3000 to start, then strop from there with cbn/poly diamond emulsion.
Also, I have DLF on their way. I know these will take care of the issue but it's good to have options...
33

Rich is this your “Rube Goldberg” Solution?

You might try Shapton’s Glass Stones

34

Here’s a quote from another Forum:

Here’s Ken Schwarz review of the Bamboo 150, I would say there is a pretty clear promotion of these over other highly regarded brands/stones…

"It’s 205x75x50 mm in size - a brick sort of burnt orange in color. And it works like no other coarse stone I’ve ever used. It cuts metal fast and it dishes slow.

It cuts faster than the 120 pro or GS, faster than the synthetic Ohmura and WAY faster than other finer grit stones like the Beston 500, Chosera 400, and other 220 and 320 Shapton stones. It leaves a coarser finish than the finer grit stones I mentioned, except the Beston 500 which doesn’t give as fine a finish, cut as fast, or dish as slowly.

So far it hardly dishes at all. This is perhaps its most valuable trait. I’ve used it on a bunch of CPM 154 Addicts to set bevel angles and a bunch of Aritsugu-As - and I have yet to have any mud from the stone to show for it. Have yet to need to lap it! The same amount of work on any other stone would give me a mud puddle. Burr generation is rapid.

I followed it with a Shapton GS 500. It was an excellent combination. I would also consider it as a starting point for going through the Chosera series - following this stone with a 400 Chosera for instance. From there I switched to some natural stones (aoto and Yaginoshima asagi) for these initial sessions with the Bamboo 150.

The 150 Nubatama Bamboo is a finer scratch pattern than the XXC DMT or Atoma 140 and is a perfect followup for them.

It is a porous stone. I would suggest soaking it for about 5 minutes first. That fully saturates the stone. You will need to add water to it to keep it wet. It isn’t recommended that you leave it soaking as it doesn’t require it.

This is a stone for removing metal. It leaves an edge suitable for slice cutting paper or coarse work. Very “toothy.” It is too coarse for a final finish but excAs accomplished a knife sharpener Ken Schwartz is (Hi, Ken!), he is also an accomplished businessman, and is in business with a few people in the knife industry, and he is the dealer for the Nubatamas, and a few other products. Not to say you can’t trust his information, and I don’t have any issue with doing business with him, and Ken is a fairly nice, decent guy, who is very knowledgeable. But just be aware that he often represents and sells the sharpening equipment you see him using and reviewing. Again, nothing wrong with that and I wish him success. ellent for repairs - chips and tips. Strongly consider this stone for work on single bevel knives."

 

35

I wanted to follow up on my progress with this knife. I received diamond lapping films from Nanolap, 6/3/1/0.5/0.1 micron. These did the trick! Much sharper thank before!! I did have the same issues with the 0.5/0.1 micron films with larger scratches showing up. I will proceed with the DLF to 1 micron, stop there and move to strops!

I really enjoy the chosera stones and will continue to use them where applicable.

Thanks for all of the input!

36

I will try the Jende 1.0/0.5 lappping film. When I have time (and my armed is healed) is have the intention to sharpen an S30 knife, my most used pocket knife or a 13C26 (my most used kitchen knife) using all grits from 100-1500 stones and then the DLF. And perhaps some strops. It is my intention to make microscope photographs after every stone/DLF.

If I have time I also want to try to repeat this on a very wear-resistant steel (see another topic).