Experienced Serrated Edge K390 users wanted.

[JSumm]

So I have very little experience with serrated edge. I have been using it since last summer with one in my back pocket almost everyday. Most of my VG-10 SE is in a Wharncliffe blade, which is why I'm asking the question.

Both models in K390 SE (Delica & Endela) have loss the tips of teeth in the same place. Maybe two serration patterns back from the tip. Most likely from cutting down on a flat surface. Could have been from a countertop or cutting board. I'm not exactly sure. My VG-10 Wharncliffes don't see the same angle in cutting obviously, so I don't have anything to compare against except H2 in a Salt 2. That one has held up fine including digging up weeds in the ground.

So just curious what others have seen from a durability standpoint on serrated edged K390 as far as the teeth or at least the tips of them. I want to grab some VG-10 with belly so I have something to compare against. Starting to think sticking to H2, LC200N, or VG-10 may be better than K390.

This is the Delica. The Endela had two teeth in the same spot that just bent over.

******Edited 4/8/24 2:21pm - This is after a week or two with the knife. Initially used CBN Rods to begin reprofiling and only used Brown/White rods to hit the actual edge.*******

[Bill1170]

My K390 Endura was reprofiled on the 15 dps Sharpmaker setting and has taken no such damage. Maybe I’m just more careful?

It could also be that reprofiling got me past the weaker steel affected by heat during the grinding of the serrations. K390 seems to be very tough for a steel of its wear resistance.

[Giygas]

I've had the exact opposite experience, but I also reprofiled mine out of the box.

I got some pretty severe chipping in my SE bd1n p3lw, but I've used my SE k390 Endura a whole lot harder and haven't seen any chipping at all.

[JSumm]

I have been re-profiling every chance I get, but it is very slow going. Plain Edge K390 after a bit of sharpening seems extremely durable at the edge.

[RustyIron]

I have three K390 knives with serrated edges, which have seen heavy to light usage. I just examined one under magnification. There is a lot of inconsistency of the serration tips, indicating wear through use. I don't consider this a problem, and would expect to see similar wear on any serrated knife that gets used.

A serrated knife is like a plain edge knife, but with 20 delicate tips. If you took your plain edge knife and did all your cutting with the tip, you'd expect to see wear or chipping. Expect to see similar wear at the tips of the serrations. If you write an equation describing the strength of the material as it comes to a point, the you'll see that it approaches 0.

My suggestion is to carry your knife daily, use it like you stole it, sharpen as needed, and don't worry. It appears that you've been sharpening the knife, but it looks like you're missing the edge. You're hitting the back side of the bevel. You might be happier if you increased your angle a bit. Anyway, that's what I'd think about doing.

[WilliamMunny]

In general...

The harder you use a knife the tougher steel you will need. In very simple terms when pushed to its limits steel will either bend, dent, etc. or chip/break. The tougher the steel is the less likely it is to break but will lose it's cutting edge considerably faster. (Note that the Spyderco serrated edge is so good that even a dull knife will still cut well.)

H2 and L200C are both tougher steels than K390 but will need to be sharpened considerably more often. K390 is a very well-balanced steel combining decent toughness and good edge retention and will keep an edge 2 to 3 times longer than H2/L200C but again if pushed it is more likely to chip, crack, break, etc.

VG-10 is a good entry level steel but K390 is both tougher and more wear resistant. I would expect if you were breaking teeth off of K390 you would have even worse performance with VG-10.

As noted sharpen your serrated edge K390 at a steeper angle. For one it does not appear you are hitting the edge and second a steeper edge will dramatically increase the toughness of the edge and make it less likely to chip.

Good luck, K390 is great, good at everything an all-around steel, but if you need extreme toughness stick with H2.

[JSumm]

Hey,@RustyIron , yes, this knife along with the other SE blades are either a main carry or back pocket carry everyday and get used. A lot. And not a bit of worry has popped up in this little brain of mine. I am just curious if I am better off sticking to something like H2, LC200N, or VG-10 for SE. In plain edge, I can abuse that K390 edge and with not too much effort get it back in shape.

Good point on tips . Makes me think steels like H2 and LC200N are better suited for SE afterall??

As far as the sharpening, yes the shoulders are more worn/sharpened. I have been using the corners of the CBN rods to slowly re-profile everytime I touch up on the SM. I have only used the Brown rods and White rods on the actual apex. And as we know, ceramic kinda polishes K390. If there was a finer Diamond or CBN rod, I would use that on the actual edge. I am afraid the current CBN offering may be a bit too coarse.

[JSumm]

Keep in mind, that picture was a week or two after getting the knife. So you are seeing, an initial CBN rod to reprofile and only Brown/White on the actual edge.

Imagine with me that the edge has been a bit more polished and the shoulders are even more worn down with an extra couple of months of whittling away at it the SM. I'll try and get some updated pictures later today...

[endura3]

I'm a big K390 fan in both SE and PE - for most of this year an SE Delica has been my most used/carried knife. I love SE K390 for a couple reasons:

1. They have (IMO) the thinnest blade and serration geometry of any SE knives spyderco offers.

2. For my uses, (mostly fibrous abrasive material like cardboard, plants, mulch bags and other gardening supplies, plus miscellaneous utility work such as stripping wires, etc.) SE K390 offers fantastic wear resistance with enough edge stability to generally avoid the kind of chipping damage you saw here.

3. Relatedly, I haven't found that sharpening has been much of a chore relative to other steels I've used extensively in SE like VG10, LC200N, and H1/H2.

As a couple other posters have pointed out though, the points of serrations are innately a little more fragile than the edge of a PE blade as there's simply less material supporting the edge at those points. And these K390 serrations are real thin. I wouldn't stress too much about one or two teeth exhibiting the kind of chipping you experienced, but if it happened regularly with my uses I would probably instead prefer to use a tougher SE knife.

I'd say "tougher knife" and not "tougher steel" because the steel is just one piece of the puzzle here:



Bottom is an H2 Salt 2, and top is the K390 delica. While H2 is obviously a much tougher steel, it's also much softer, and I'd imagine that with equivalently thin geometry the H2 would sustain similarly severe damage if not worse in equivalent use (although the dulling mechanism would be rolling/blunting and would be easier to fix).

However, as you can see, the geometries aren't equivalent: the H2 is not only thicker behind the edge but also has slightly wider, more "spaced out" teeth. I don't have a picture of the LC200N SE Salt 2, but its BTE thickness probably sits about between these two with the same larger/wider teeth as the H2 S2. I'm not sure how VG10 FFG serrations compare as I only have an LT3LW in that configuration and the blade is so much stouter it's hard to draw conclusions relative to the Delicas.

However, in equivalent geometries I'd expect VG10 would take either rolling or chipping edge damage more readily than K390, while concurrently being easier to repair. That being said, my most used SE VG10 knife is an Endura 3 with a Sabre grind and I've found the teeth on that both thay one and the LT3 are exceptionally resilient. But again, I think that's primarily due to the way stouter blade geometry on those models (although both are still more effective slicers than you'd expect for various reasons - SE geometry sure is complicated).

Anyhow, if I know I'm gonna be doing something that will damage the edge, I take SE H2 or LC200N for the above reasons. The steel is tougher and the overall blade geometry is stronger, so you do typically see a bit less edge deformation with equivalent use IMO.

Obviously the tradeoffs relative to SE K390 are decreased abrasive wear resistance and decreased cutting performance due to the thicker blade geometry, but if you're finding that SE K390 chips a lot in your use cases that may very well be the right direction to look.



^roughly organized from bottom to top by perceived cutting performance in use (K390 Delica being the best performer) - overall edge toughness would probably be about the reverse.

And again, if this chip is something that just happened once or twice, particularly with a relatively new knife, I wouldn't worry about it. Edge damage can be kind of an enigma if you aren't paying super close attention in use, especially with a newer knife that still has a factory grind when you're not familiar with the max stress it can take or how to optimally sharpen it yet. But I've cut pretty thick buckets in half with SE K390, sliced electrical wires, and that kind of more "abusive" stuff without issue. But if I'm opening two dozen bags of gravel or quickrete I'm either grabbing a different cutting tool or spending a little more time than I'd like with a CBN rod lol. It really just depends what you find works for your uses.

[JSumm]

All good points guys! I may pick up a Leaf Jumper in VG-10 SE to replace that exact model I lost back in the summer. At least to compare to the Endela in K390. The Endela did not break off at the same point as my Delica, but rather bent at the same tips. After that damage, I cut through some plastic material on my wife's van that was the equivalent of a 5 gallon bucket with no issue. I don't think I could have done that with plain edge.

Here is the current state. Not even halfway through reprofiling. Hard to see, but you can see that the micro serrations from the grinding wheel are gone at the edge. That is from sharpening the edge with the brown and white rods. Shoulders being sharpened with CBN.



From the sound of it, it looks like you guys would still choose K390 over VG-10 or LC200N? I have a Salt 2 in H2 and to me that is a different beast. I think it is way too thick for my uses, but I bought that model for beach and lake time.

[endura3]

From the sound of it, it looks like you guys would still choose K390 over VG-10 or LC200N? I have a Salt 2 in H2 and to me that is a different beast. I think it is way too thick for my uses, but I bought that model for beach and lake time.

Corrosion notwithstanding, I do prefer SE K390 to SE LC200N in "slicey" FFG knives. I experience a good deal more rolling and blunting at the tips of the serrations with FFG SE LC200N for my specific uses. I'm not sure how VG10 would compare with equivalent FFG SE geometry (rather than the much stouter VG10 SE knives I do have), but I'd guess it would perform at least slightly better than LC200N given the somewhat higher hardness and better wear resistance. I'd be curious to hear more from folks that own FFG SE knives like the leafjumper or Stretch 2 XL though - it's one of my favorite all-around steels between its balance of properties, ease of sharpening, and relatively low cost, and I would definitely recommend SE VG10 in general based on the performance of my LT3LW and Endura.

I don't think FFG VG10 would be a better performer than K390 all else being equal, but it's certainly much easier to sharpen and repair and it's a fantastic steel in its own right. And a leafjumper would be a great comparison for the Endela as well, as I'm pretty sure they both have the same .118" blade stock.

[Bill1170]

From experience I will say this: when the CBN grinding on the shoulder reaches about halfway to the edge, you are about a quarter of the way done with reprofiling the knife. The reason for this is that you are removing progressively more steel as your reground bevel grows wider. The last millimeter takes an eternity to finish because you’re grinding essentially the entire scallop surface at that point. Keep on, it’s worth the effort.

[JSumm]

Thanks @endura3. Lots of food for thought. I'm going to keep using these 2 in K390 and see how they hold up. At the end of the day, I have used these for all kinds of stuff and they are a pleasure to use. I still have a Rock Jumper and Endela in SE VG-10, but being Wharncliffes I don't feel it is a fair comparison. So the LJ still may be my choice to try out.

@Bill1170 that is correct. With each session, this painful truth of reprofiling SE is in the back of my mind trying to destroy every piece of positive attitude I thought I had. Honestly, I gave up the idea of reprofiling right away with my first SE model the Leaf Jumper in VG-10. I had it for a couple of weeks before I lost it, and quickly realized I did not have the will power to stick with it in the first week. I settled on being content with doing a bit here and there as the edge needs a touch-up. I basically spend 10-15 or 20 minutes with the CBN rods at the 30deg slots then spend a minute or two touching up on the 40deg with the ceramic.

Off topic - Now that I type this, I recall @Evil D mentioning the Native 5 Magnacut SE being right about 15DPS from the factory. That may be a better option for someone to try out, though unfortunately being a bit thicker blade stock then some of the Seki options. Not sure if the LC200N and S30V SE Native 5's come with the same edge angle.

[cjk]

…

Off topic - Now that I type this, I recall @Evil D mentioning the Native 5 Magnacut SE being right about 15DPS from the factory. That may be a better option for someone to try out, though unfortunately being a bit thicker blade stock then some of the Seki options. Not sure if the LC200N and S30V SE Native 5's come with the same edge angle.

I am able to sharpen my SE Native 5s (and lil Natives) using the 15 degree position on the Sharpmaker out of the box and it microbevels. I have S30v, Magnacut, and S35vn. LC200n is the only one I don’t have, but I’d be willing to bet it’s the same. It’s probably just a matter of time until one drops in my lap though, maybe on a MAP holiday or a smoking deal on a used one. Believe it or not, S30v is the only one of these in have not encountered noticeable point damage of some kind. I use my SE S30v lil Natives more than anything else.

They really do get better as time goes on. In order to really teach myself to sharpen SE, I bought a tired SE Native 5 and a borderline beaten SE lil Native. Both were practically butter knife dull with worn points.
With worn points, but now sharp, the SE Native 5 now cuts better than a new one.

I’m kinda veering off topic, I actually think the SE lil Native cuts much better than the SE Native 5 (new or used or whatever). I can’t tell why, but it does. It doesn’t cut as well as the K390 SE Delicas, but it’s pretty great.

[JSumm]

I am able to sharpen my SE Native 5s (and lil Natives) using the 15 degree position on the Sharpmaker out of the box and it microbevels.

That's pretty incredible. Saves a lot of time. I wonder if they're doing that because the Native has a thicker blade stock. Would be awesome if the Seki models came that way, but like you said they have their own advantage of thinner blade stock like the Delica example you gave.

[Brock O Lee]

...this painful truth of reprofiling SE is in the back of my mind trying to destroy every piece of positive attitude I thought I had...

Kudos to all of you who has the courage and patience to reprofile K390 SE on the Sharpmaker.

Here is a story about H1 SE, but could also apply to K390 SE with the Sharpmaker.

I gave heavy H1 SE edge repair a shot before with the SM and (worn) diamond stones. It was not a full reprofile, just an attempt at smoothing out snaggy tips, and resetting a uniform bevel again after I had botched the teeth and bevel on a few previous freehand attempts.

I thought H1 would not be too much of a challenge, but I was going nowhere slowly, and it did not take long before I had a sense of humour failure. So I clamped a DMT Diafold coarse conical file onto one of the Sharpmaker stones. This was a lot more productive, especially when grinding on the up and down strokes. The angle was slightly off, but it was easy to compensate for by tilting the blade or shimming the SM base.

After that ordeal I am happy to leave all my SE factory bevels unmolested, and simply apply a micro bevel come sharpening time. Especially for K390.



I think that was not too shabby


Maybe this nasty hack might speed up your journey @JSumm ? This worked for H1, but it should also work for K390. In theory any diamond file should eat through K390 about as quickly as H1?

Unfortunately the SM triangles are not ideal for reprofiling, because there are not a whole lot of abrasive particles on the diamond/CBN stone edges, and they disappear quickly over time as you wear them away with pressure. The DMT file has a lot more horsepower in my experience, and is less likely to shed particles because it is round.

[JSumm]

Thanks @Brock O Lee! That does look more effective. Honestly, I am not too worried about it. The reprofile that is. A little here and there and always more time with a courser abrasive should mean eventually it will be reprofiled. I actually ended up with that mindset with VG-10 and H2 as well last year.

Now @cjk confirming what @Evil D had mentioned on the Native 5's factory angle is intriguing. A lot more steels to choose from as well. I do wish D was active and could chime in. I know he tortured tested a bunch of SE Steels including his last reported test on Magnacut. I don't recall what he found on K390...

[R100]

Thanks @Brock O Lee! That does look more effective. Honestly, I am not too worried about it. The reprofile that is. A little here and there and always more time with a courser abrasive should mean eventually it will be reprofiled. I actually ended up with that mindset with VG-10 and H2 as well last year.

Now @cjk confirming what @Evil D had mentioned on the Native 5's factory angle is intriguing. A lot more steels to choose from as well. I do wish D was active and could chime in. I know he tortured tested a bunch of SE Steels including his last reported test on Magnacut. I don't recall what he found on K390...

When I received my Magnacut Native 5 SE I was very pleased to find that it was more acute than 15° - no need to reprofile. My UKPK SE Salt is the same so I wonder whether all Golden SE is very acutely ground. The teeth on both mine are big and pointy though so some people won't like that.

I am a veteran of a number of reprofiling jobs on H1, LC200N and VG10 and they are all very time consuming. I use very light strokes to preserve my CBN rods and every knife has taken thousands of strokes. H1 is certainly no easier than the others so you have my sympathies Hans.

After the last of many harrowing experiences with reprofiling SE I had decided that was it, no more, any subsequent SE knives I buy will be used at the factory profile and be sharpened at 20°. Unlike Evil D, I sharpen the back side of the serrations pretty close to the primary grind, just to remove the burr.

I had decided to avoid K390 SE because I thought it would be too hard to reprofile and just deal with in general. Then K390 SE was discontinued and discounted... First I bought the Endura because it is my long term favourite pattern and was ridiculously cheap. I loved it, the retention of high level sharpness is way better than any of my other SE steels and I have yet to inflict any damage to it. Next I bought the Police 4 version and it has become one of my favourite Spydercos ever. Recently I added the Delica and now have a K390 SE trio - the best value knives I have ever bought.

Despite my resolution, I decided to give reprofiling the Delica a go with my by now well worn CBN rods and started today. Maybe I'm crazy but it doesn't seem any more difficult than with the other steels I've done and I am already most of the way through. The Delica is obviously a small blade and that's why I am doing it but I did my LC200N Salt Wharncliffe when the rods were much newer and it was a real chore.

Just my experience but I'd rate K390 my favourite SE steel. I have an excellent SE testing medium in a large vigorous clumping grass - Setaria sphacelata - which I have to endlessly cut away from around my fruit trees where I don't want to compact the soil with my tractor. This has a high silica content and is an edge killer. For direct comparison - the K390 Endura stays sharp way longer than either my H1 or LC200N Pac Salts in this use.

Sorry for the extended rave but it is a subject close to my heart.

Dan

[JSumm]

Thanks Dan @R100 that's good to know. And glad you got the family in K390. I picked up a lot at the discontinued prices. And my experience with trying to reprofile VG-10 has not proven any quicker than K390. Why I decided to just do a little at a time. Carrying my Endela in K390 SE today.

[JoviAl]

I don’t know if it is at all helpful but I do pretty much exactly what Hans does using a conical diamond file. Where I differ slightly is that I clamp the knife blade teeth pointing out into a ball and socket bench vise (one that rotates in all directions that I use for holding chainsaws by their guide bars for chain sharpening) and adjust it so that I can go at it from a comfortable angle. Works quickly and gets a consistent angle, but I only do it for reprofiling as it really hogs metal out.

I treat reprofiling as a separate exercise to sharpening. With H1/H2 I’m toying with the idea of doing it with my Foredom and some conical diamond burrs I normally use for porting, but haven’t bothered yet as the hand method is adequately rapid.