I'm planning on testing out some of the techniques and tools I have from my stone carving experience. I am thinking it will act more like stone than steel when sharpening so I am thinking very fine diamond on various materials.
I have soft backed diamond wheels going up to 50k as well as diamond pastes and powders that work well on leather, wood, paper, etc to figure out what works. I also use cerium oxide and other polishing compounds on leather with some types of stone and will be trying those out too.
This sounds like the most compelling philosophy I've yet heard going into this, looking forward to hearing how it turns out with the soft-backed diamond wheels.
I don't have access to the same tools, but I'm going to try and keep "stone carving" in my brain while I'm sharpening this mule. My first strategy in mind is to work with with F800 and up resin-bonded diamond stones, some careful stropping, who knows what we'll find...
go slow, be patient, and remember that the bur will be very, very delicate--one pass too many could wreck it, so check the edge often, alternate sides frequently, and hold the angle precisely. Slow and steady wins the sharpening race.
Please clarify? Ceramic creates a burr? Don't want to wreck the burr?
Yeah, you know, the sharp little razor edge you get from the initial sharpening on a more aggressive stone and then even out with a finer grit or maybe even a strop depending on the edge and the steel. Not every steel will get a bur--or at least I'm not talented enough to get one on the hardest super steels--and it isn't necessary if you're just touching up a working edge, but it's the best method I know of for getting a dull edge sharp again. When done correctly the blade looses just a tiny bit of material off the cutting edge so that it's still very sharp but not as fragile. Am I using the term "bur" wrong? I know someone who uses the term "apex" to describe it, but as a verb, which is sloppy English and sounds a little...lewd...to my ears, so I stick with "bur." In any case, the ceramic knives I sharpened would most definitely get that delicate razor edge after many passes on the stone, but being ceramic it was extremely thin, too thin. It probably would have chipped if used for even normal cutting, and after a couple of attempts I learned that I needed to stick to a fine grit and be sure to alternate which side of the blade I was sharpening after just a couple strokes. Hopefully that makes sense; apologies again if I'm misusing a common sharpening term.
Interesting.
I think you are using the term "Burr" a little off. And more properly describing the apex, and even microbevelling a little if I am reading you correctly.
I'm just not sure I've ever encountered a burr on a ceramic knife. (I'm not sure they can really form a burr in the traditional sense.) That said, I've only ever tried to sharpen a handful of ceramic knives before, and never one of this exact composition.
In my mind the burr is formed when your edge gets to apex and small amounts of steel "bend" over the edge and don't get shaved off by the stone. Thereby creating a small lip on the opposite edge from where you were sharpening. Since ceramic is much more brittle, and not flexible or malleable (in the usual sense of the word) then I'm not sure it can technically form a burr like we are used to. In softer steel it can form a really pronounced burr that you can easily feel and will even catch your fingernail when you try to slide it over the edge. (stropping removes this burr and finely polishes and slightly aligns the apex edge.
I wonder if a tiny burr is actually the phenomenon that you are experiencing or if there is something else entirely going on there. I know I'm definitely interested in trying a few techniques to figure out what works for this new material.
As Sal has said before, "The edge is a ghost"
Yeah I would be really surprised if ceramic could form a burr. I find it can be difficult to form a burr even on very hard, carbide rich steels like 15V/10V.
The general term I hear in regard to burrs forming is "plastic" deformation. Not to be confused with plastic in the sense of petroleum based materials. But it's also descriptive of the way a material behaves under certain mechanical forces. But the basic thing that I understand is that most materials over 65 HRC can't deform plastically, and carbide-rich steels can be a mixed bag because the matrix itself is soft enough to, but the carbides aren't, so depending on the carbide content you might have more or less success getting a burr. But when it comes to a ceramic, there's nothing like a iron matrix to speak of, and so it's not very likely to deform plastically.
On the other hand with this HIC, there's something about it that increases the toughness, so maybe it will increase the ability to deform plastically and form a burr.
I have some relatively inexpensive gritomatic diamond stones (240/600/1200) I've used with a worksharp using the gritomatic upgrades. I've had good success getting very hard steels (e.g. Rex 76) back to screaming sharp. I've had *very little success* getting kyocera ceramic knives back to sharp using the same setup, so not entirely sure how this is gonna go with the HIC. I might have to try and find a different/better set of stone grits or something.
My plan is to try a linen belt loaded with diamond compound on the 2x72 with a rubber contact wheel. I’ve never sharpened anything like this but if this doesn’t work I’ll probably go to fine diamond stones. I read that these should be done with pretty fine grit to avoid chipping, so my thought was to go in kind of a reverse order from normal and start out with fine and work towards coarser grit if necessary. Part of me figures that worse case I mess this all up and send it back for factory sharpening
The linen belt sounds reasonable. I have a 2x48 belt grinder. Where does one source linen belts? Thanks!
Steel novice who self-identifies as a steel expert. Proud M.N.O.S.D. member 0003. Spydie Steels: 4V, 15V, 20CV, AEB-L, AUS6, Cru-Wear, HAP40, K294, K390, M4, Magnacut, S110V, S30V, S35VN, S45VN, SPY27, SRS13, T15, VG10, XHP, ZWear, ZDP189
My plan is to try a linen belt loaded with diamond compound on the 2x72 with a rubber contact wheel. I’ve never sharpened anything like this but if this doesn’t work I’ll probably go to fine diamond stones. I read that these should be done with pretty fine grit to avoid chipping, so my thought was to go in kind of a reverse order from normal and start out with fine and work towards coarser grit if necessary. Part of me figures that worse case I mess this all up and send it back for factory sharpening
The linen belt sounds reasonable. I have a 2x48 belt grinder. Where does one source linen belts? Thanks!
I’ve been happy with the ones from Klingspor. It looks like they have a 2x42, but I didn’t see a 2x48.
My plan is to try a linen belt loaded with diamond compound on the 2x72 with a rubber contact wheel. I’ve never sharpened anything like this but if this doesn’t work I’ll probably go to fine diamond stones. I read that these should be done with pretty fine grit to avoid chipping, so my thought was to go in kind of a reverse order from normal and start out with fine and work towards coarser grit if necessary. Part of me figures that worse case I mess this all up and send it back for factory sharpening
The linen belt sounds reasonable. I have a 2x48 belt grinder. Where does one source linen belts? Thanks!
I’ve been happy with the ones from Klingspor. It looks like they have a 2x42, but I didn’t see a 2x48.
Also, I flip some of my belts inside out once they wear out and put different diamond compounds on them. They are usually some form of tight woven fabric and work pretty good like that.
Every day in my pockets, Wallet, Keys, Phone, Light, and Knife.
Got HIC mule today and worked on sharpening it as it was not very sharp at all on arrival. I Have venev diamond stones and was attempting to match current angle apprx 18 dps but not super consistant so i knew lots of work was ahead. Started with 400 but it was SLOW!! Dropped to 240 and when I finally apexed and evened both sides it started micro chipping. When running a fingernail on edge it felt same as running it down the length of the knife. You'll see but knife feels ribbed if you drag a fingernail down its length Immediately went back to 400, then 800, 1200, 2k. Then finished on 3 micron, .5 micron and .1 micron diamond loaded leather strop plates. Got tired at about 1 hr mark and finished up last stone and strops quickly. In the end it will just shave arm hair but isn't what I'd call really sharp. I'll use it how it is now and see. I will say it's a monster to sharpen compared to spydercos other hard high wear steels. Best of luck!!
Got HIC mule today and worked on sharpening it as it was not very sharp at all on arrival. I Have venev diamond stones and was attempting to match current angle apprx 18 dps but not super consistant so i knew lots of work was ahead. Started with 400 but it was SLOW!! Dropped to 240 and when I finally apexed and evened both sides it started micro chipping. When running a fingernail on edge it felt same as running it down the length of the knife. You'll see but knife feels ribbed if you drag a fingernail down its length Immediately went back to 400, then 800, 1200, 2k. Then finished on 3 micron, .5 micron and .1 micron diamond loaded leather strop plates. Got tired at about 1 hr mark and finished up last stone and strops quickly. In the end it will just shave arm hair but isn't what I'd call really sharp. I'll use it how it is now and see. I will say it's a monster to sharpen compared to spydercos other hard high wear steels. Best of luck!!
Dude, arm-hair shaving is a miracle with this material.
Mine came from the factory dull as sin. I really mean it...
I measured the geometry with a laser goniometer... The primary blade grind is 1 degree per side. The edge grind is 17 degrees per side. Then there was a 30+ degree per side microbevel on it. If was smooth... But too smooth.
I reprofiled on an Atoma 400 grit. Microchipped it to ****, so I tried to get those out with a 1200 Atoma as best I could, but it didn't seem to help any. I switched to a DMT EF that's about twice as fine as the Atoma 1200 and it is FINALLY starting to bite onto my finger pads on a 3 finger test, and can barely draw cut receipt paper, but I just can't seem to get it any better than this.
Not gonna lie, I kinda hate it. I don't know... Even if I do manage to get it decently sharp over however-many-hours of rubbing it against this DMT, I don't really know if it's worth it. If it's anything like super steels and drops that front-end sharpness almost immediately then I will absolutely hate it.
At this point though, I don't even know if I'm going to be able to get it to the 100 BESS baseline I usually test at. Debating whether to buy a bunch of diamond spray to make some strops, or cut my losses now and just resell it. Hopefully someone else with a BESS tester will do some testing to show how it holds front end sharpness to help me decide. So far the only person I have seen test this stuff is Cedric and Ada and I don't find his testing method to be very informative about the qualities I'm hoping for.
I got mine today. It's so dull that it won't cut through construction paper.
If the factory can't send me a usable edge, I'm not going to waste my time and diamonds on creating one with soklme random exotic material. I'm just weirded out that they would see that edge and say "yes - we will definitely send that out".
I received mine yesterday. Opened one box, took out the knife and felt the edge. It felt quite dull, so I tried cutting the cardboard shipping box, which it did cleanly. When I got home and got it cord wrapped I tried whittling a bit on a hardwood project I had laying around. It worked better than I expected, but I wouldn't try any detail work as it felt rather like a steel knife that needed sharpening. Bottom line, it will do the things I usually do with my knife, just not as pleasantly. After a couple of hours on the DMTs, it is getting much better. Interesting material.
As you can see, I don't have all the grinder gouges out yet, but it's getting there.
I got mine today. It's so dull that it won't cut through construction paper.
If the factory can't send me a usable edge, I'm not going to waste my time and diamonds on creating one with soklme random exotic material. I'm just weirded out that they would see that edge and say "yes - we will definitely send that out".
It's disappointing as ****.
It's their boldest innovation yet: Knives that aren't sharp. :P
Got mine last night too and also disappointed at it not being very sharp. I've had experience with this material before in Rahven kitchen knives and there too i was disappointed that some knives were not very sharp, but some were sharp. With those knives another issue was that they were thin and flexible so sharpening them is even tougher. I was hoping that Spyderco would do a better job at sharpening these and because mules have stiff blades I was really hoping to see what this material can really do. Now, I don't know if Spyderco can't sharpen these well then I question if I'll be able to. I understand that the Mule project is to experiment and learn about different steels and materials, but was really hoping for a sharper knife from the factory.
If shaving hair is difficult or impossible for most sharpeners with this material, it suggests that the material is not capable of getting to a thin enough cross section at the apex. This can happen with steel by formation of a burr but in this case I wouldn't expect much burr formation. I would suggest that what may be happening is micro-chipping at the apex. As in it's chipping as it's getting thinner and basically may reach a point where it's not capable of getting thinner as it just keeps chipping away. I would really say this is a good case where a decent quality USB micro-scope would help a great deal to folks.
If this is the case, it would suggest that using a finer abrasive may minimize this effect. Somewhere around 800-1200 JIS would be a good place to start but may be painfully slow, especially if you are not hitting the apex directly (color with a sharpie to visually confirm). You can even just elevate the knife angle slightly over the edge angle to work on a micro-bevel rather than plane the whole edge bevel down. This will of course cause the knife geometry to thicken much faster when you do not work the edge bevel at each sharpening but it works much quicker to bring the apex to a keen thickness (thin).
Some other things to try :
-Grind a light flat on the apex at 90 degree angle (barely visible) which will allow you to see when you are ready to apex.
-Grind only using ultra-light force to minimize lateral stress on the apex which could cause micro-chipping.
-Begin grinding edge bevel until light stops reflecting from the flattened apex, which happens just before apex formation.
-Then switch to a finer stone and elevate above edge angle a small amount to finish apex with a micro-bevel.
-Use only edge leading strokes rather than edge-trailing or scrubbing motion, both can cause problems potentially
-Cross scratch pattern and/or use strokes which are mainly perpendicular to spine when apexing to finish.
As many others have said, out of the box my Mule did not seem to be especially sharp. It would cut printer paper but had a tendency to snag and tear, and it wouldn’t shave arm hair. I will say that before doing anything to it I tested it out on some double thick cardboard that I had and it handled it very well.
This afternoon I had time to work on sharpening this Mule, and as planned I used the contact wheel on my 2x72 with a linen belt loaded with 1 micron diamond spray. I knew this wouldn’t fully reprofile the edge, but I will say that I was very pleased with the results. After about three minutes of working the edge it is now shaving nicely, and slicing paper much smoother than it was out of the box. I’ll be interested to see how long it keeps this level of sharpness.
This evening I got the chance to play around on my grinder a bit more and it has me feeling good about grinding this material for when I need to put a whole new edge on this thing. I decided to work the spine of the knife on the contact wheel using a 1000 grit belt just to see how it grinds. The results were pretty great in that I was able to grind most of the spine to a smooth polish in a matter of minutes. If I am able to grind the spine smooth that quickly hopefully I can work the edge in a similar fashion.
I couldn’t seem to get a decent picture of the edge, but here is the spine after the 1000 grit belt
Amateur maker of folding knives and addicted to modding Spyderco knives
This evening I got the chance to play around on my grinder a bit more and it has me feeling good about grinding this material for when I need to put a whole new edge on this thing. I decided to work the spine of the knife on the contact wheel using a 1000 grit belt just to see how it grinds. The results were pretty great in that I was able to grind most of the spine to a smooth polish in a matter of minutes. If I am able to grind the spine smooth that quickly hopefully I can work the edge in a similar fashion.
I couldn’t seem to get a decent picture of the edge, but here is the spine after the 1000 grit belt
What type of 1000 grit belt did you use? was it a diamond belt or some other abrasive material?
Every day in my pockets, Wallet, Keys, Phone, Light, and Knife.
