CPM 15V Sprint sharpening and performance thread

[Bemo]

Interesting. I don't know what your experiences are with s110v, but it will dull, often through microfracuring which leave a micro-serratedge that keeps cutting/sawing through cardboard for quite some time. From your description,this sounds different.

[RustyIron]

Interesting. I don't know what your experiences are with s110v, but it will dull, often through microfracuring which leave a micro-serratedge that keeps cutting/sawing through cardboard for quite some time. From your description,this sounds different.

Yup, the behaviors of the two materials are definitely different. I've only used S110V for a short while, but have experienced what you describe quite a bit with K390. Since both materials maintain usable edges even after the degradation, I can't say at this time which I like better. Both are easy to fix... maybe 15V will prove easier... but only time will tell.

[Bemo]

From a podcast with Larrin and Shawn over a year ago, 15V has about as much Vanadium as you can stuff in a steel. Shawn has really come up with an amazing heat treat if it doesn't microfracture as much as other steels then. Almost a shame that the hardest thing mine is used on is routine cardboard.

[electro-static]

Some advanced sharpening tips.

Dress the resin stones, remove the clogged metal on the surface. This will provide a cleaner cut bevel with less burnishing from clogged metal rubbing and preventing the surrounding diamond from interacting due to the clogged metal being taller causing the bevel to ride over the diamond on the clogged metal.

As you progress from each grit the knife should be sharp enough to cleanly slice paper. After each grit, draw the edge across the next grit and make a new burr and remove as much as possible on the stone before finishing on a strop.



Factory Edge is ~17dps

Durability starts at +20dps for any steel.

Every new knife owner knows this day will come, but I didn't think it would be so soon. I got home last night, sat down, and removed everything from my pockets. I flicked open my knife in a manner that might have sent the knife flying across the room and most certainly took years off the life of the lock. I gave the edge a quick feel and... whaaaat? The edge wasn't as sharp as expected. I stuck the knife under the scope and found a 3/4" missing apex.

Then it hit me... while opening a gift and slicing a ribbon, I met resistance. The ribbon had two lengths of wire running through it. It was a ribbon, and I had a knife, so something had to give. I hacked through the ribbon and thought nothing more of it. And now I got to see what happens after CPM-15V cuts through wire.

The knife was certainly still usable, but now I had an excuse to rub the edge on some rocks. The stones were Edge Pro diamond matrix. I started with 80 grit to get the geometry close two where I wanted it, then 250 and 650 to pretty it up. If I had a goniometer, it come in at about 24 degrees. With a factory edge, it usually takes me a couple sharpenings before I get rid of the imperfections. The new Manix is no different. There's still some wonkiness near the tip and the heel, and one side should be taken down a little more. I can't see it with the naked eye, but I can feel that it's not as sharp as it should be, and the scope shows why. There's no sense in chasing the ghost right now. The knife is sharp enough for general purpose use. I'm sure within a week, the OCD will kick in and I'll refine the edge some more. I spent half an hour sharpening the knife--less time than it took to take the pictures and type this out.

Hogging down the edge
IMG_9387.jpeg


Diamonds on the 15V cut quickly, as one would expect
IMG_9386.jpeg


After half an hour I got bored. Good enough.
IMG_9388.jpeg


The other side isn't quite apexed, but I don't want to show the ugly side.
CPM-15V 2.jpg

Thanks BBB! I’ve been struggling with my veneve diamond stones most of the time they just make my knives duller, I just bought a nagura stone to dress them.

[msum]

Thanks BBB! I’ve been struggling with my veneve diamond stones most of the time they just make my knives duller, I just bought a nagura stone to dress them.

Does Shawn sometimes use “Magic Eraser” to clean diamond stones? Or did I misunderstand/misattribute an Instagram post…?

Obviously doesn’t help flatten them… Glass and SiC powder seems to be the way, if I understand correctly. Although I don’t know what grit of SiC powder or the best clean-up method after. Wash off (down drain?), I assume.

[vandelay]

From a podcast with Larrin and Shawn over a year ago, 15V has about as much Vanadium as you can stuff in a steel. Shawn has really come up with an amazing heat treat if it doesn't microfracture as much as other steels then. Almost a shame that the hardest thing mine is used on is routine cardboard.

18V and 20V existed in an experimental form at one point. https://knifesteelnerds.com/2021/05/24/ ... n-you-add/

[Bemo]

Hey there Vandelay, that's why I used the qualifier "about". Thanks for the article reminder. In it Larrin said that higher Vanadium steels are very hard on the refractory in the PM process. In the talk he also mentioned that as well as the clogging of the spray nozzle due to the high vanadium content. What what nice to see in this article is his toughness numbers being equivalent to 20CV/M390. Certainly makes you wonder how Shawn's heat treat protocol would test out.

[WilliamMunny]

Hey there Vandelay, that's why I used the qualifier "about". Thanks for the article reminder. In it Larrin said that higher Vanadium steels are very hard on the refractory in the PM process. In the talk he also mentioned that as well as the clogging of the spray nozzle due to the high vanadium content. What what nice to see in this article is his toughness numbers being equivalent to 20CV/M390. Certainly makes you wonder how Shawn's heat treat protocol would test out.

That is why I think/hope this knife is special. It will have edge retention approaching Maxamet levels but toughness closer to K390/10V. With steel to get something you always have to give up something. Since Shaun handpicked the batch of 15V and had a special heat treat protocol we might have gotten something pretty special giving up very little to get more performance.

[vandelay]

I decided to sharpen mine today. The factory edge just wasn't as sharp as it could be and there was a tiny chip in it.

I was worried 15V would be as annoying to sharpen as maxamet but it got razor sharp really quickly. It feels about as easy as k390. I'm using DMT plates so steel removal isn't a problem but I find some steels take a lot of extra work to get really sharp and some never feel razor sharp. The only steel I have that I find easier to get sharp is LC200N.

[kennbr34]

I have been using Shapton Pro stones and DMT diamonds, and I'm really surprised at how well it sharpens up on both. Though, I have to say, I haven't really gotten it as sharp as I get a lot of other knives, but I think that's probably just because I'm not really used to the knife itself--for me it's a lot of finesse with pressure that really gets those uber-levels of sharp. I have been hitting within 125-175 BESS pretty consistently with my touch-ups, which is pretty respectable--basically the same sharpness as a utility razor. What I tend to do is just touch it up until I can run it through my beard hair an feel it start catching the hairs, and it takes very little time to get there. If I cut up a bunch of cardboard until it's no longer shaving arm hair, I can get it back to catching my beard hairs within 2-3 minutes.

What I am curious to see is a really exhaustive test with it. I cut up what was essentially 2 cu. ft. of cardboard with it and felt like it would still keep going through lot more. So it's kind of that old tale of high-vanadium steels keeping a working edge for a very long time, but not necessarily a fine-edge. However, given how quickly it goes back to very fine, that's fine with me (pun intended).

Anyway, definitely mirroring your experience vandelay. Any concerns of this steel being hard to sharpen have not come to fruition for me, even on humble aluminum oxide abrasives.

[TkoK83Spy]

Hidden staples under thick packaging tape surprised me...nothing major, but was surprised to see this little bit of damage. Not worried about it, should sharpen away fairly easily. 15V is indeed "human"

[RustyIron]

Hidden staples under thick packaging tape surprised me...nothing major, but was surprised to see this little bit of damage. Not worried about it, should sharpen away fairly easily. 15V is indeed "human"

Cool. You never know how far you can push the envelope unless you push it outside the envelope.

[Bluhrb]

Haven't done any sharpening yet, but I'll probably reprofile the edge to 17 degrees on a WSPA. Will let you know how it turns out!

[Cycletroll]

Just started in on my 15vM2. Cut 120 feet of cardboard with factory edge and it still sliced receipt paper! Stropped back to Hair popping.
Used my 400 CBN bench stone to square the swoop in the blade at the plunge grind. Sharpened on DMT to fine (800). Sharpened quite predictably with minimal burr. Can feel the toothyness of the carbide volume on the stones, cleanly cuts paper towel. Let the cardboard destruction begin!

[Strauss95]

I sharpened my 15V Manix a couple of days ago, still had a decent edge but I wanted to even out the bevels and grind the bevel back to the plunge grind.

I started with the Venev F150 to grind the bevel at the plunge, and had to reprofile one side to match the other. All done freehand, the F150 stone handled business extremely quickly. Once I reached the apex and formed a burr on both sides I moved up to the Venev F240, which was where I hoped to stop. Like many high hardness steels it seemed to deburr fairly easily on the stones, but in the end I wasn't happy with my Bess score even after stropping on 1um diamond on leather. Best I could get on my Bess tester was a score of 250 off the F240 stone and light stropping.

So I spent some time on the Venev F400 stone and followed with a light stropping once again on 1um diamond on leather. After that progression I was able to dip under 200 on the Bess tester with a 175 reading. Still lots of bite on the edge which is what I was hoping for.

I'm still working on my freehand technique and find I really struggle getting a very sharp edge off a coarse stone. Technically the edge "feels" very sharp, able to cut paper towel and shave arm hair, but find I'm always in the 250-300 range on the Bess tester off a coarse stone. I assume I'm struggling with burr removal, not completely sure. I have seen others achieve sub 100 Bess scores off a coarse stone and strop combo so I know it's possible. I've only been freehand sharpening for about a year now so I still have a lot to learn, I've been trying to practice almost every day.

Using the Venev stones the 15V sharpened very easily for me, noticeably easier than Maxamet.

[TTFulltimer]

Haven't had a chance to use it yet. Factory edge measured at 16 and 19 degrees. Sort of dreading evening the bevel out. Been sharpening a Maxamet Manix off and on for the last few days. Reprofiling Maxamet is a very slow process (using a guided system). I'm hoping 15V will be easier to work with. The trade off od course is once you actually get it sharp it's got great edge holding.

My edge bevels were a mess. 14 on one side and 17 on the other. The grind was uneven with elevated ridges about 1/32 inch long that were raised adjacent to a clifflike drop for a bit.

I use a Ruixin Pro 009 with a rack and pinion mod for the slide bearing holder. I have a set of Venev Ursa diamond stones. Since the edge was such a mess it did not cut out of the box worth a darn. I set it up in the sharpener and started with the 150 grit on the 17 degree side but had the stone set to cut 14 degrees. I worked until the bevels were about even then went up to 200 grit and worked a burr back and forth twice. Went through the progression up to 1500 grit (2 micron) and then finished on diamond grit on leather 1 micron and then .5 micron. I was able to eliminate 95 percent of the original gouges with just a few very thin hair like marks now. The edge is truly scary. I inadvertantly touched the edge with my fingertip and had a 1/4 inch slice that I did not even feel until I saw blood. Weather has not been conducive to me being outside to use the knife. And I had to wait for a zirconium ball to fix the screwball lock. It was sticking with the metal ball. The sharpening with the Venev stones was just as easy and any of the other steels I have. Rex 45, XDP, Magnacut, D2, 154, and 14C28N. I do not use any regular stones now. To totally reshape the edges and get to the final polishing on the strop was about 15 to 20 minutes.

[TTFulltimer]

I will be going camping over this vacation, always gives my knives a workout (even K390) will let you guys know how it performs. Maxamet microchips when handling some wood tasks, K390 doesn’t. So this should be an interesting comparison.

Just make sure not to commit the biggest sin in knife testing, testing for steel when in fact you are testing differences in geometry.

Will do! Everything will be profiled to the same angle on a KME system, 17 dps, 600 grit finish 4um CBN, 1um diamond, 0.25um cbn on leather for stropping.

Do you think I should go more acute?

That's a good place to start, if you see damage you can increase to a thicker angle (skip 18,19 to 20°dps) and if the cutting ability is not to your liking you can always lower it (skip to 15°dps)

I think a lot of us have to realize though that serious durability for any knife, any steel starts at 20° per side and up. This is especially true for fixed angle systems.

With freehand there is more convexity happening towards the apex at the perceived angle held at the shoulder with the angle convexing thicker by ~1-5° per side depending of the sharpener coordination, abrasive, skill, etc

For example, you can have a freehand guy/gal holding 17° at the shoulder and its actually convexed to 20° at the apex.

So these Degrees per side values are not universal between all of us and there can certainly be "perfection through omission" happening.

One of the biggest problems in our community is that not all of us have access to laser goniometers to see how the light reflects off of the angles we think we are making; there can be some convexity at the apex hiding boosting the perceived durability we are getting at a given angle or hindering sharpness and cutting ability if severe enough.

So, its mind numbing to see folks saying " My 18° per side edge on Steel A can hold 18° no problem, your 18° per side edge on Steel B cannot, must be because its Steel B"

Nope, have to rule out geometry out first.

If the laser ain't reflectin, than geometry you ain't detectin


Keep in mind, this isn't a big deal for personal use, I don't need people losing their minds running out to get goniometers or misinterpreting what I'm saying here that you need some fancy piece of equipment to enjoy your knife.

No

The goniometer is if you're more serious about making conclusions about steel by helping further rule out the biggest barrier (geometry) to observing the steel in order to compare apples to apples.

After all

Geometry, geometry, geometry.

I saw a YT video where a guy used a cat torture laser pointer and a marked up sheet with angles as a makeshift goniometer. When I first saw you using a CATRA version, of course calibrated, I looked them up on Amazon. $38 USD, of course not certified but most likely good enough. A fixed angle sharpener and a Sharpie do a decent job to determine the unknown angle. And if used very carefully the fixed angle sharpener makes a known edge angle. I reset on every knife flip to be sure I am on the correct angle. Bit of crazy engineer in me.

[TTFulltimer]

Some advanced sharpening tips.

Dress the resin stones, remove the clogged metal on the surface. This will provide a cleaner cut bevel with less burnishing from clogged metal rubbing and preventing the surrounding diamond from interacting due to the clogged metal being taller causing the bevel to ride over the diamond on the clogged metal.

As you progress from each grit the knife should be sharp enough to cleanly slice paper. After each grit, draw the edge across the next grit and make a new burr and remove as much as possible on the stone before finishing on a strop.



Factory Edge is ~17dps

Durability starts at +20dps for any steel.

I use the Venev Ursa two sided stones. I put on water with a bit of dawn dish soap on the stones when starting on a bevel and wipe them off after each bevel sharpening. If I see a little metal piling up on the blade I stop and wipe down the stone and the blade. Very little metal is left on the stone. When I am done with all the progressions, I put some Ajax cleanser (just what I had) on the stones and use them in pairs with the flat sides against each other, a little bit of rubbing and they are better than new.

For this 15V I have watched as much as I could find on your channel about it. I remember one video where you suggested 14 degrees per side for a good slicey edge with decent durability. That is what I have put on my edge. It also was pushed in that direction since one factory bevel was already at 14 degrees. I took down the 17 degree side then worked both sides once I had an even bevel and good apex. I had to take off quite a bit to get rid of some really bad gouges in the factory grinds.

[TTFulltimer]

Just an FYI on Venev stones. They use the FEPA F description for "Grit" Most water stones use the JIS. To compare them it is best to microns that are the equivalent. I poked around and found some equivalency charts. Put together this little comparison. FEPA P is the grit for paper. That URL works to see the little chart. No idea why the image tags did not work.

http://digphoto.net/images/GritSizes.jpg

[Ramonade]

For the grit chart I like to refer to this one : https://www.gritomatic.com/pages/grit-chart

I don't know if it's something people can really see in that awful video taken with the front camera (sorry for the mess in the background).
But just 2 passes on leather loaded with 1 micron gunny juice has given me excellent results when it comes to maintaining the edge a lil' bit. I'm not even close to having to resharpen !