Sharpening stones

[OakTree]

I'd like to sharpen my S110 Para3 and (eventually) my Cruwear Dragonfly 2. I have the Sharpmaker and a 3D printed sharpening system that uses the KME style stones. I don't even know what type of stones I currently have. I bought them online from AliExpress (https://www.aliexpress.com/item/32875261768.html).
What kind of stones do I need to sharpen S110 and Cruwear?

[kobold]

Diamond or CBN is the safe bet.

[FK]

I like the DMT diamond, the S110V has high vanadium and will be very slow to sharpen with conventional stones. Low cost Chinese diamond will work initially however, wear away rather quickly.

Regards,
FK

[OakTree]

I like the DMT diamond, the S110V has high vanadium and will be very slow to sharpen with conventional stones. Low cost Chinese diamond will work initially however, wear away rather quickly.

Regards,
FK

Thanks. Can you recommend a stone that will fit my system? I'm no good with freehand sharpening. What grit levels do I need?

[vivi]

sharpmaker works just fine for sharpening those steels.

Look into diamond stones for reprofiling and repairing damage.

[jpm2]

Thanks. Can you recommend a stone that will fit my system? I'm no good with freehand sharpening. What grit levels do I need?

Diamond or cbn triangle rods for the sharpmaker. (Just reinforcing that point here)
Can't help with anything from aliexpress.

Grits from 100 up to whatever finish you want, and a couple beyond.

[Spook410]

There are expert sharpeners on this forum. I'm not one of them so with that caveat...

Nobody can tell you what will fit your 3D printed sharpener with AliBaba stones. The stones according to one buyer are 20mm X 150mm X 5mm so if there are diamond or CBN stones with those dimensions they might work. For me, it would be a 160 grit for initial sharpening with a 400 grit to finish. The S110V would probably benefit from going to a 1000 grit. Then you need a strop with chromium oxide (YouTube will answer any questions on these) to finish.

As for the diamond rods or CBN rods on the Sharpmaker, I think they something like a 400 grit mesh. Should work well enough for what you're looking for. Would still get the strop to finish.

Finally, if you have trouble with free hand on a regular bench stone, you can try these to get your angles right: https://www.amazon.com/dp/B01N4QMO7U?ps ... ct_details

[sal]

Hi Oak Tree,

What ever method you use to restore an edge on your knife, I always recommend a magnifying loupe about 10X - 12X. this will permit you to actually SEE what you are doing on the edge as you sharpen. It will enhance your edge-u-cation.

There is a learning curve, so be patient and persistent. Also, anything from Aliexpress is in question. If you have a Sharpmaker, I would suggest you begin with that. Watch the instructional video and pay attention to what you are doing. It will help you understand the process.

sal

[aaronkb]

Hi Oak Tree,

What ever method you use to restore an edge on your knife, I always recommend a magnifying loupe about 10X - 12X. this will permit you to actually SEE what you are doing on the edge as you sharpen. It will enhance your edge-u-cation.

There is a learning curve, so be patient and persistent. Also, anything from Aliexpress is in question. If you have a Sharpmaker, I would suggest you begin with that. Watch the instructional video and pay attention to what you are doing. It will help you understand the process.

sal

Awesome advice. I’ve always had trouble completely removing the burr, and I finally got a loupe… it enabled me to initially see but then learn to feel burrs smaller than I could see or feel before.

[FK]

One of the most important steps in sharpening is burr removal. With plain carbon steels this is easy,,, the real difficulty is with the high vanadium steels and high Cr content steels. These steels form a very small and tough to remove burr.
Good lighting and 10x-15x loop will easily show the small burr which is very difficult to see unaided.

I use free handed sharpening and have not pursued the fixtures and small stones so popular today. To check the actual angle of bevel and micro bevel, a set of plastic wedges is used with bench stones. Then a series of thin hard leather with diamond compound for final polish of bevels.

The Sharpmaker and Spyderco ceramic bench stones are excellent and I have used them for almost 30 years. Be careful not to press to hard and use too long or you will easily form a tough small burr, then complain it does not work very well on the newest tool steels.
Form a micro bevel with clean DMT Extra Fine bench stone to remove the burr,,,, final light passes on diamond leather to refine the apex.

Regards,
FK

[JD Spydo]

Diamond or CBN is the safe bet.

No argument there at all. But don't overlook any of Spyderco's great ceramic stones. If nothing else they are particularly good for finishing work for these newer supersteels.

But you are spot on using both the CBN and diamond stones for reprofiling and doing your primary work. Rapid stock removal sure saves a bunch of time.

[kobold]

Diamond or CBN is the safe bet.

No argument there at all. But don't overlook any of Spyderco's great ceramic stones. If nothing else they are particularly good for finishing work for these newer supersteels.

But you are spot on using both the CBN and diamond stones for reprofiling and doing your primary work. Rapid stock removal sure saves a bunch of time.

That's right! The Spyderco UF is always my finishing stone no matter the steel, and especially with S110V, it is often necessary to raise a burr twice on each side with the UF for true shaving sharpness.

[Vaugith]

Cruwear is an easy to grind and sharpen steel. Your current stones will most likely handle it fine. S110V is a much more difficult to grind steel and will require some more heavy duty abrasives to assure you are cutting the steel and not burnishing it.

I'm personally not a fan of reprofiling very wear resistant steels on the sharpmakers diamond or CBN rods, but there are many folks here who have done it and it works for them. Its a very slow process and your angle selection is limited but it can be done.

Kmesharp.com sells diamond "Gold" stones from 50 grit to 1500 grit, then diamond lapping films down to .1 micron, as well as kangaroo leather strops and CBN emulsion down to .1 micron. They are expensive but will do the job.

Gritomatic sells a selection for the kme including Norton Crystolon and SiC stones that will cut your steels well at coarse grits for less money as well as Venev diamond plates which are *bonded* instead of *coated* and act quite differently. Note that if you change stone types in the middle of the progression you'll need to adjust the angle of the system to accommodate for differences in stone depth. You can just do the sharpie trick and confirm and adjust the angle again. Kme makes a stone depth compensator but I don't know if it would work well on your system or not, or if it's even neccesary.

Id get a bottle of honing oil and use it lightly with all of these stones.

I'd personally start with the SiCs to do any heavy reprofiling or chip repair due to their lower cost. The 50 and 100 gold stones aren't much faster than the 140 honestly and the SiC should be a similar speed. Then I'd move to the 600 and 1500 kme gold stones which I've found to be very nice and high quality. After that I'd microbevel on the sharpmaker rods of your choice, depending on whether you want a toothy or fine edge.

Alternatively for way cheaper you could just pick up a King Neo 800 or King Hyper soft 1k water stone from mtckitchen which will each cut your steels with ease, ditch the guided system, learn to get great edges on those, and still use the sharpmaker to maintain the edge between sharpening sessions.

[FK]

Research Carbide Tearout on High Vanadium steel.
The vanadium carbides are approx 15 microns in size,,, you need a apex under 1 micron for maximum shaving sharp efficiency.
The Al Oxide and SiC abrasives are softer than the vanadium carbides and will wear away the steel surrounding the carbides resulting in chunks of vanadium carbide tear out. Only diamond and CBN are hard enough to actually abrade and sharpen the vanadium carbides.

Can you sharpen a high vanadium steel with softer abrasives,,, yes,, but not as quickly and efficiently, poor edges with tear out.
Can you use ceramic stones,,,, yes, but they will mainly burnish and not cut the carbides like diamond and CBN. Small tough burrs will be formed too easily with poor apex formation.

I have a Nikon microscope with variable power and several eyepieces that gives 10x-80x magnification. This is not the fingernail or finger print test.

Another test for burr formation is to complete your favorite procedure then cut some relatively soft material like soft wood at 90 degrees to the grain. Examine again,,,,, you may be surprised at the edge burr roll over quickly formed,,, this is a wire edge that "feels" very sharp but is rather weak and will not be a strong apex well formed in the steel matrix. We see many YouTube "tests" showing "hair splitting edges". Remove that weak wire edge burr with a micro bevel using fine diamonds to cut away the stubborn burr and produce a strong apex. Many polished edges have that weak wire edge and break down very fast in actual cutting use.

Regards,
FK

[jpm2]

Research Carbide Tearout on High Vanadium steel.
The vanadium carbides are approx 15 microns in size,,, you need a apex under 1 micron for maximum shaving sharp efficiency.

15 microns seems very large for vanadium carbide, especially in a pm steel. I could see them maybe clumping together in an ingot steel?
I thought they were usually more in the 1 - 3 micron range.

[Vaugith]

Research Carbide Tearout on High Vanadium steel...

The carbide tear out debate was a hot topic for a long time, but I think at this point it is understood that carbides do not "tear out" when facing softer abrasives, but rather get scooped out at low grits or are worn down into dust at higher grits. Have you actually attempted to sharpen with coarse SiC or very soft AlOx stones on high vanadium, difficult to grind steels? I thought as you do until I put the process to the test. I also purchased a high magnification digital microscope and various abrasives just to try out. I found that diamonds are actually slower to cut, especially once the coated diamond plate starts to break in and lose some of its particles sharp corners. My soft AlOx stones and SiC abrasives cut difficult to grind steels fast, they form burrs, and they are not burnishing.

Please note that I still think it's a good idea to use diamond or CBN abrasives when polishing the bevel at grit sizes approaching the carbide size of the steel. This cleanly cuts the carbides instead of essentially wearing them down into dust. Larger grit sharpening scoops fine carbides out, but things get bound up at fine levels. But now the question arises of if these steels even perform best with carbides cut cleanly into the walls of the bevel, or with the carbides exposed and the surrounding matrix eroded away? Which slices better, and which has better resistance to crack initiation? I dont have evidence to answer these questions, but I do think it makes a difference.

You're also perfectly fine to apply a microbevel with the spydercos ceramic rods on difficult to grind steels, which use alumina as an abrasive. The contact area between the abrasive and the steel is very small in the microbeveling process which allows force to be multiplied and the abrasives to cleanly shape the apex.

If you don't want to take my word for it, go check out the article on the scienceofsharp blog called "carbides in maxamet" to see some SEM microscope images that prove the point.

[Steeltoez83]

I think this micrograph Larrin made for s110v tells the whole story. I can't speak for other ppl and their own experiences but the steel is saturated with carbides. Putting a high polish just doesn't make sense to me. What does make sense to me is that I will face a high volume of hard carbide at every stone I throw at s110v. And a very high edge polish is almost pointless due to the size and sheer volume of those carbides. Just makes sense to follow a diamond/cbn progression on s110v and put those carbides to work.