Sharpening stones to use with modern powder steels

[maximus83]

M maximus83 , I might have mis stated "fine SiC". Mine are jb8 double sided and suspect they're more like coarse/medium. Neither of them are made in mexico, so they might be different.
The Norton jb8 and Eze-Lap 61F should come in around $50. Knifecenter has good selection and prices.
Yeah, if I removed metal at the same rate with diamonds, as I do with SiC, the diamond plate won't last long. My diamonds are mainly for touch ups, truing, and crisping the edge after a full sharpening.

The current 2-grit JB8 that I have and see sold on various places like Sharpeningsupplies.com, says coarse and fine grits, 120/320. Dunno if the older ones were different. Mine was made in Mexico. Regardless on that, your setup is good and with the single stone rather than the 2 separate, it's awesome that you can basically land 3 good grits, finishing with diamonds, for around $50. You and Yonose are running in the lead for most low-cost minimal sharpening setup that's a little better than say a Norton economy stone, and can also handle super steels.

 

[jpm2]

M maximus83 , I distinctly remember a listing of 100/280 grit, don't know if it was for the economy, JB8, both, or if they changed grit rating, or actually changed the grit.
I guess all this means is, there's a lot I don't know.

 

[maximus83]

I guess all this means is, there's a lot I don't know.

Me too. I took SharpeningSupplies.com word for it, where I get a lot of my stuff, see their FAQ on this page and their linked grit chart which suggests 120/320. Again this is for a recent one, made in Mexico. Looking at Norton abrasive catalog, they don't put an actual number on the Crystolon, looks like it could be anywhere from 100 to 120 for C, and 260 to 320 for F. Either way, they work awesome.

ETA, I found the difference: SharpeningSupplies says on their grit page they use JIS numbers, vs Cami.

 

[microtech85]

This one is sharpened with spyderco double stuff medium ceramic, progressing to fine ceramic, then about 5 passes on each side with strop loaded with green compound. It is not mirror finish, nor was that the intention. I for one am not a fan of mirror finish except for as a show knife. So far my favorite cutting performance is ending at medium ceramic then doing a few passes on strop to ensure burr and wire edge free edge. Some of Maximus83's prompted me to experiment with different stones. I sharpened one knife with SiC, another with eze-lap fine diamond, another with dmt fine diamond, then all finished on medium ceramic then to loaded strop for a few passes. Then i did one on just SiC and ended with a few passes on loaded strop. I may make a video to demonstrate how each one does.

 

[maximus83]

Little more experimentation this afternoon. 2 tests, same knife. It's worth pointing out here, in my OP for this thread and the question about what materials should be used to sharpen HC steels, I meant what you need for a full end-to-end sharpening process, including edge profiling as mentioned in the OP.

The knife: A Ritter MK3 fixed blade, S30V, had only ever touched up the factory profile on this one since I owned it, never reprofiled. It was extremely dull, also had a big chip in the main straight part of the blade caused I think by batoning with it through some Douglas Fir.

I did 2 full reprofile and end-to-end sharpenings of this same blade, using 2 different methods for comparison.

1. Sharpmaker + SiC: Sic stones (150/400/600 progression) + SM fine ceramic + strop with 10 micron diamond compound. I worked on this for 1.5 hours, nearly all of that on the Sic stones, making swipe after swipe doing a full reprofile to 15 dps (factory looked 18 to 20 range) and repair the chip. I made headway maybe reducing the chip size by about 1/3, but it was taking too long and I gave up. The knife was sharp, it would take off arm hair with friction or push-cut newsprint, but it was not smooth and effortless and of course it would snag anywhere around the chip in the blade. Adequate for real world use, good and sharp, but not as good as I can get with my other knives or what I'd hope for after that much effort. Of course the time involved in this test had nothing to do with ceramics or SiC, it was taking so long because of trying to full profile an edge on an HC steel knife with the small, inefficient SM stones.
2. Pure diamonds: Ultrasharp diamond bench stone (300/1200 progress) + strop with 10 micron diamond compound. I worked on this for a total of 20 minutes: did another full edge reprofile, this time to 12 dps, eliminated the big chip in the blade, apexed, and stropped. As in the first test, no micro. Most of the time was spent on the 300 grit diamond side, and good results for the 20 mins invested. Easy shaving arm hair, low friction push-cuts slicing entire chunks off of a magazine page without hanging up since the chip was gone, etc. This sharpening clearly had a superior result.

For sure, nothing amazingly new but this test just again reconfirms, if you're doing a full end-to-end sharpening of a dull knife including an edge reprofile and/or edge repairs, you really want SiC or diamonds (or something just as hard like CBN) involved at the coarse stage of the process, and preferably on a real stone that has some surface area. I don't know if the ceramics impacted on the less than optimal sharpness in test 1, or not. All I can say with certainty is that I consistently get my best sharpening results on HC steels, with the least amount of time invested, when I use diamonds. The next test I want to run though is the mixed use I mentioned in another thread today. For instance, use my Norton Crystolon bench stone for the profiling, then use the Ultrasharp 1200 mesh side to finish, and see if I get results there as good as test (2) here.

 

[Chris "Anagarika"]

I’ve used the eef in the past with mixed success, it takes more time on the uf but I think it comes out better. I’m not sure if it’s because the high grit of the eef is “overkill” for practical use though? Of course stropping compound works as well for a mirror polish

Probably your EEF isn’t well broken in (?). I read in older thread that the EEF when new can scratch it deeper than EF. I have one old & well worn and one new (broken in).

 

[microtech85]

I just made a video of myself doing a sharpening demonstration on ceramic sharpening stone. I dulled blade with two passes on diamond stone and then sharpened the zt 0450 on the medium side of spyderco double stuff. I chose to use the double stuff to demonstrate that an affordable $30 ceramic stone can sharpen cpm steels. Of course with the knife this dull, the diamond stones would have been faster to bring up the burr. The sharpening took a little less than 8 minutes to bring it to an easy arm hair shaving/partial hair popping edge. I did the sharpening hunched over my coffee table and used the doublestuff on the table for demonstration purposes instead of in the hand like i normally do. So here it is, video 1 of 2. I will try to get the second one loaded tomorrow.

 

[DeadboxHero]

I just made a video of me doing a sharpening demonstration on ceramic sharpening stone. I dulled blade with two passes on diamond stone and then sharpened the zt 0450 on the medium side of spyderco double stuff. I chose to use the double stuff to demonstrate that an affordable $30 ceramic stone can sharpen cpm steels. Of course with the knife this dull, the diamond stones would have been faster to bring up the burr. The sharpening took a little less than 8 minutes to bring it to an easy arm hair shaving/partial hair popping edge. I did the sharpening hunched over my coffee table and used the doublestuff on the table for demonstration purposes instead of in the hand like i normally do. So here it is, video 1 of 2. I will try to get the second one loaded tomorrow.

I'd just move that blade back and forth to speed it up.

 

[microtech85]

I'd just move that blade back and forth to speed it up.

I sometimes do the back and forth technique when my blade is really dull, but for this video i was trying to demonstrate the basics. For some reason i have never done it on my ceramics, i only do it on my diamond and SiC stones when i am trying to bring up the burr fast.

 

[David Martin]

M maximus83 , I distinctly remember a listing of 100/280 grit, don't know if it was for the economy, JB8, both, or if they changed grit rating, or actually changed the grit.

jpm, I think your closer to correct. DM

 

[Yonose]

Probably your EEF isn’t well broken in (?). I read in older thread that the EEF when new can scratch it deeper than EF. I have one old & well worn and one new (broken in).

I may own a defective one, for all I know, since I only have one.

 

[microtech85]

Here is the second part of my sharpening video. I pick up where i left off when my battery died. It is me demonstrating the edge i put on with just a medium ceramic stone and then stropping.

 

[microtech85]

I found my sharpmaker manual. Here is a pic of page 3. It talks about sharpening any metal known to man and being a 9 out of 10 on hardness scale. They recommend the diamond stones specifically for, "aggressive re-shaping, re-beveling, or re-profiling a cutting edge". The sharpmaker manual is a very thorough and written with detailed instructions and with useful illustrations.

 

[David Martin]

Whoa, 'can cut any steel known to man'. They did'nt mention a word about vanadium carbide tear out. DM

 

[jpm2]

M maximus83 and David Martin , that Norton Abrasives catalog seems to explain the difference in dealer listing grit size, good find.

It also seems high grit silicon carbide stones are allergic to oil, all I can find are waterstones.

 

[David Martin]

Do you mean they recommend against using oil on a Spyderco ceramic stone? DM

 

[jpm2]

Guess I should have said SiC, instead of synthetics.

 

[microtech85]

Whoa, 'can cut any steel known to man'. They did'nt mention a word about vanadium carbide tear out. DM

I am thinking about this "carbide tear out" and it seems to me that the carbides are so much harder than the surrounding steel that when sharpening with a diamond or anything else, the metal around the carbide would be worn away long before the carbide could be sharpened and would therefore will be abraded away. This effect may be only further exacerbated on blades under 60hrc. And on steels like s30v only 4 parts of 100 are vanadium carbide. Maybe try putting 96 small marbles on the floor, then drop 4 of the larger, "breaker, striker" type marbles in the mix. That would be like s30v i can imagine.
It just doesn't seem to add up to anything for me. I understand the theory though, but it just seems wrong to me. Plus, whether i sharpen with diamond or ceramic i end up with equally sharp edges. If there is a difference, it is completely imperceptible to me. Even if it is possible to get sharper off of a diamond, i am already able to pop hairs and slice paper towel clean and i am not sure if a sharper edge would lend any significant cutting difference.
Plus, i am happy ending my sharpening session on a medium ceramic. With diamond, i am not satisfied with fine or extra fine, and i don't find it cost effective to spend a lot of extra money for several thousand grit stones just to end up with the same feeling edge as a fine ceramic.
I do not mean to offend anyone with this post. I know it flies in the face of the accepted school of thought here. And this is just my opinion and thought process based on over a decade of sharpening experience and thought on the subject. I will be happy to hear a good argument for why i may be wrong though.

 

[maximus83]

jpm, I think your closer to correct. DM

Both are correct, they're using 2 different grit rating systems: JIS, and CAMI. You just have to be clear about which one's being used. SharpeningSupplies.com and some dealers use JIS, others use CAMI. Norton shows both in their grid chart. Some abrasive sellers like @FortyTwoBlades helpfully show multiple grit ratings on their products, which I find quite useful when they take the time to do that. Also convenient is @adamlau recently posted an updated unified grit chart in the maintenance forum sticky on grand unified grit chart. What kinda blows my mind is there are so many different ratings systems, and trying to compare them when you look at 2 different abrasives and figure out can I use these together as part of the same sharpening process or not. I find this one of the most confusing aspects of sharpening, especially when not using abrasives that are all from the same maker.

 

[maximus83]

Here is the second part of my sharpening video. I pick up where i left off when my battery died. It is me demonstrating the edge i put on with just a medium ceramic stone and then stropping.

I enjoyed the vids, and no offense meant but seems like spending a lot of time arguing against a straw man that nobody disagrees with. You are not doing a full edge profile like I did in my test, you are simply touching up and re-apexing an already nicely beveled edge. I don't expect too many folks here would think you couldn't get that blade sharp under those conditions. You say in one of these vids: there's a lot of chatter about whether ceramics can sharpen these steels. Not really. I'm not aware of many folks in the forums that would argue that ceramics cannot sharpen HC steels at all. A lot of the regulars here already use ceramics in some way themselves, for instance it's common to use ceramics as a niche role to refine an edge at the end of sharpening process. Clearly, ceramics "can" cut steel. But it's also true that you "can" use your toothbrush to clean your garage floor, but I doubt you'd want to.

The really interesting question I think is whether ceramics SHOULD be used in a primary sharpening role, and whether they are "optimal" compared to the other alternatives for sharpening HC steels. I get it that you would answer yes, but there are a LOT of pro sharpeners here who would answer no to this specific question. Myself, I'm undecided, but based on mixed results from years of earlier ceramic use and good recent success with diamonds and SiC, I am inclined in that direction. Your video does not speak to the issues raised in some of the other recent threads in the forum that raised significant detrimental issues when using ceramics with HC steels. See this thread as a recent example of the discussions. And my post here tried to summarize some of the issues. DM mentioned one--potential carbide tear-out which is still being debated on all sides, but there are others. If you want to do future interesting tests and videos that may have the chance of changing some minds, it would be interesting to instead do some tests that target the issues discussed in threads like the linked one, and see if you can show those concerns are either unfounded, or that there is a workaround. I am certainly open to new info myself, and always looking for ways to improve sharpening process and materials.