Sharpmaker and sharpening SERRATED K390 - expectations?

[Wartstein]

I am really looking forward to the serrated K390 Endura (ffg!! :) )
Now I wonder how sharpening the serrations in this very hard steel on my sharpmaker will work out.

- Obviously I can only use the corners of the rods
- I can recall Sal saying something along the lines that reprofiling SE blades with the corners of the rods should be done with a lot of care (if at all) since the wear on the corners can be substantial
- So: What do you think? Would you touch up serrated K390 just on the brown (or even white) rods and just take more time? Or take them (again, for touch ups, not reprofiling!) to CBN/diamonds?
- And would actual reprofiling of serrated K390 work in a realistic amount of time on CBN or diamond rods?

I know, no one (except Spyderco) has experience with that specific matter yet, I am just interested, since I never had serrations in such a hard steel (and I think in the past the only comparable thing was serrated ZDP, right?)

[JMM]

I still have a ton to learn in terms of sharpening any serrated blades, but in terms of sharpening a PE K390 blade I don't do anything different than I do with something like a Rex45 blade and it seems to work well for me. That said, I'm really looking forward to the plethora of FFG SE K390 in our collective future, being able to move past VG10 will be exciting & educational for me at least... my favorite SE EDC knives like the Lil' Matriarch, Wharnie Delica, Endela, etc are pretty much all VG10 with a couple exceptions. I'm certainly more excited for these than any other SE knife I've purchased to date. What about other users, do you anticipate sharpening SE K390 to be much different than SE VG10 in terms of basic mechanics/techniques?

[Wartstein]

I still have a ton to learn in terms of sharpening any serrated blades, but in terms of sharpening a PE K390 blade I don't do anything different than I do with something like a Rex45 blade and it seems to work well for me. That said, I'm really looking forward to the plethora of FFG SE K390 in our collective future, being able to move past VG10 will be exciting & educational for me at least... my favorite SE EDC knives like the Lil' Matriarch, Wharnie Delica, Endela, etc are pretty much all VG10 with a couple exceptions. I'm certainly more excited for these than any other SE knife I've purchased to date. What about other users, do you anticipate sharpening SE K390 to be much different than SE VG10 in terms of basic mechanics/techniques?

What I am thinking about is that the corners of the rods obviously wear a lot faster than the flats. And of course with SE one can only use the corners.
It is just that I have no experience at all concerning sharpening hard steels in SE on the sharpmaker (just H1, VG10, and stuff like 420 HC and whatever Victorinox uses).

[JMM]

I still have a ton to learn in terms of sharpening any serrated blades, but in terms of sharpening a PE K390 blade I don't do anything different than I do with something like a Rex45 blade and it seems to work well for me. That said, I'm really looking forward to the plethora of FFG SE K390 in our collective future, being able to move past VG10 will be exciting & educational for me at least... my favorite SE EDC knives like the Lil' Matriarch, Wharnie Delica, Endela, etc are pretty much all VG10 with a couple exceptions. I'm certainly more excited for these than any other SE knife I've purchased to date. What about other users, do you anticipate sharpening SE K390 to be much different than SE VG10 in terms of basic mechanics/techniques?

What I am thinking about is that the corners of the rods obviously wear a lot faster than the flats. And of course with SE one can only use the corners.
It is just that I have no experience at all concerning sharpening hard steels in SE on the sharpmaker (just H1, VG10, and stuff like 420 HC and whatever Victorinox uses).

I gotcha.... FWIW I'm 100% in the same boat, the only SE blades that I use & sharpen on the reg are VG10, I have a couple H1 and a S30V knife that are SE but again, I rarely if ever carry or sharpen them. This will be a learning process I imagine for a bunch of folks... I'm excited! :D

[Cambertree]

I’m interested and excited to try K390 in SE as well.

It might take a while, but I daresay you could use the CBN or diamond Sharpmaker rods to apply a more acute edge. I’d probably do it in a few sittings if I was to attempt it.

I respect Sal’s advice regarding the wear on the diamond/CBN Sharpmaker rod corners, of course, but personally I don’t have an issue with the understanding that sharpening abrasives are ultimately consumable items of kit.

I take good care of my stones and other sharpening gear, but they are there to be used and will all wear out one day.

Some, like the white ceramics may well outlast me though!

I can report that I’ve ground my K390 Dragonfly to measured 9dps and it has held up fine as a work knife. I do run it with a light 15dps microbevel though.

Most factory Spyderco SE edges I’ve put on the goniometer so far are in the 17-19 degree inclusive range.

Not drying the edge after cutting wet material, can cause a more noticable effect on K390’s edge apex fineness over time, than dulling by slow wear, in my experience.

[nerdlock]

I’m interested and excited to try K390 in SE as well.

It might take a while, but I daresay you could use the CBN or diamond Sharpmaker rods to apply a more acute edge. I’d probably do it in a few sittings if I was to attempt it.

I respect Sal’s advice regarding the wear on the Sharpmaker corners, of course, but personally I don’t have an issue with the understanding that sharpening abrasives are ultimately consumable items of kit.

I take good care of my stones and other sharpening gear, but they are there to be used and will all wear out one day.

Some, like the white ceramics may well outlast me though!

I can report that I’ve ground my K390 Dragonfly to measured 9dps and it has held up fine as a work knife. I do run it with a light 15dps microbevel though.

Most factory Spyderco SE edges I’ve put on the goniometer so far are in the 17-19 degree inclusive range.

Not drying the edge after cutting wet material, can cause a more noticable effect on K390’s edge apex fineness over time, than dulling by slow wear, in my experience.

Hey Cambertree,

Did you use your sharpmaker to do this?

[GarageBoy]

What options are there? You got the cbn/diamond rods, the congress moldmaster silicon carbide rods, the dmt (I think only one available grit, and it's tapered, so you run the risk of reaming out your serrations) - no bonded cbn/diamond in triangle, right?

[bearfacedkiller]

It will be very easy to strip the diamonds off the corners of the rods due to the increase pressure (psi) when using the corners.

I wrap my rods with sandpaper to reprofile se and some pe. You can go through paper quick but it saves the rods.

I have no experience with K390 and I am still new to serrations but I have reprofiled SE S30V on my Shaman. It went well but my serrations were ground at exactly 15 degrees and they worked perfectly with the 30 degree slot on the sharpmaker. This will be the main criteria that determines SE K390’s ease of sharpening. If the angle is too obtuse it will be a challenge. If it comes in around 15 degrees then it shouldn’t be too bad.

I might grab an Endela but I really want a Police4. There is confirmation that we will see a SE Police4 but I am unsure if it will be K390 or VG10? I like big knives but the Endura is an ergonomic nightmare for me.

[Evil D]

Ive used diamond and CBN rods to sharpen Maxamet so I'm not real concerned. I'm pretty excited to try it out.

[Wartstein]

Ive used diamond and CBN rods to sharpen Maxamet so I'm not real concerned. I'm pretty excited to try it out.

Yes, but not Maxamet in SE... , so you probably (mainly) used the flats?!

Do you think the much smaller surface of the corners of CBN or diamond rods will do the job without wearing out to much on the hard K390? (Honest question, I have no idea)

[Evil D]

Ive used diamond and CBN rods to sharpen Maxamet so I'm not real concerned. I'm pretty excited to try it out.

Yes, but not Maxamet in SE... , so you probably (mainly) used the flats?!

Do you think the much smaller surface of the corners of CBN or diamond rods will do the job without wearing out to much on the hard K390? (Honest question, I have no idea)

It's a concern with any steel, I'd say more so with a higher wear resistant and harder steel so patience will definitely be important. People will be tempted to press down harder to speed it up and that'll definitely wear out the rods.

[vivi]

Brown rods work fine for sharpening K390. You'll want diamonds or CBN for reprofiling though.

[Wartstein]

Brown rods work fine for sharpening K390. You'll want diamonds or CBN for reprofiling though.

You think CBN or diamonds will be good for reprofiling serrated K390 without wearing out too much?
I have no experience with SE blades in real hard steels so don´t know...

[sal]

There is confirmation that we will see a SE Police4 but I am unsure if it will be K390 or VG10?

Hi Darby,

the plan is for both.

sal

[vivi]

Great news Sal! I'm eager to try a SE Police 4!

Brown rods work fine for sharpening K390. You'll want diamonds or CBN for reprofiling though.

You think CBN or diamonds will be good for reprofiling serrated K390 without wearing out too much?
I have no experience with SE blades in real hard steels so don´t know...

Yes. My diamond rods have reprofiled multiple SE knives and still cut fine.

[bearfacedkiller]

There is confirmation that we will see a SE Police4 but I am unsure if it will be K390 or VG10?

Hi Darby,

the plan is for both.

sal

:D You are too good to us!

[Cambertree]

I can report that I’ve ground my K390 Dragonfly to a measured 9dps and it has held up fine as a work knife. I do run it with a light 15dps microbevel though.

Hey Cambertree,

Did you use your sharpmaker to do this?

Hey Nerdlock,

Definitely not. :D I used the Atoma 140 benchstone to do about 90% of the thinning out. Then went up through the rest of the Atomas (400, 600, 1200) and the Venev OCB 800/1200. I like a clean looking edge grind, so I usually finish with the Spyderco UF 3” x 8”, although I’m not concerned with putting a mirror polish on.

Then I usually use the brown Sharpmaker rods at 15 dps to microbevel and resharpen with. Sometimes I’ll use the M or UF rods.

I think using the right tool for the job is important. The Sharpmaker is a very versatile tool for what it was designed for, but there’s better methods for thinning out edges.

Although I haven’t seen a discussion of this point anywhere, Todd Simpson in the scienceofsharp blog has identified sub surface damage to steel under the ‘ploughing’ grooves made by abrasive particles, so I feel it’s possible there may be some advantage to using abrasives which allow the job to be done with the minimum number of passes. Also the resin bonded diamond stones may also help in this regard, as only the ‘points’ of the diamonds are exposed above the binder matrix.

https://scienceofsharp.com/2019/10/02/g ... ge-part-1/

In this case with K390 in SE, we have an interesting situation, as we can’t really use benchstones for reprofiling, and yes, there will be wear on the corners of the CBN/diamond rods from using them in this way. Light pressure would be vital, and even this pressure will be greatly magnified by the tiny contact area.

I personally wouldn’t be racing to reprofile my K390 SE to 15 degrees inclusive. Although the steel is very impressive in thin edges, it’s still run a fair bit harder and has a high carbide volume relative to some of the established ‘high performers’ in SE edges, like H1, VG10, LC200N, CTS-BD1N, 52100 etc.

When I get my first K390 SE, I think I’ll just use the brown Sharpmaker rods and the Goldenstone/Doublestuff 2 and an Idahone cylindrical ceramic rod to progressively hone the existing serrations as I touch up the edge. This will also round over the spike serrations a bit.

My last Seki SE edge, the LC200N Pac Salt 2 is a fair bit shallower in its grind than the old skool spiky serrations, so hopefully this is an ongoing CQI adaptation on the SE Seki knives.

[nerdlock]

I can report that I’ve ground my K390 Dragonfly to measured 9dps and it has held up fine as a work knife. I do run it with a light 15dps microbevel though.

Hey Cambertree,

Did you use your sharpmaker to do this?

Hey Nerdlock,

Definitely not. :D I used the Atoma 140 benchstone to do about 90% of the thinning out. Then went up through the rest of the Atomas (400, 600, 1200) and the Venev OCB 800/1200. I like a clean looking edge grind, so I usually finish with the Spyderco UF 3” x 8”, although I’m not concerned with putting a mirror polish on.

Then I usually use the brown Sharpmaker rods at 15 dps to microbevel and resharpen with. Sometimes I’ll use the M or UF rods.

I think using the right tool for the job is important. The Sharpmaker is a very versatile tool for what it was designed for, but there’s better methods for thinning out edges.

Although I haven’t seen a discussion of this point anywhere, Todd Simpson in the scienceofsharp blog has identified sub surface damage to steel under the ‘ploughing’ grooves made by abrasive paricles, so I feel it’s possible there may be some advantage to using abrasives which allow the job to be done with the minimum number of passes. Also the resin bonded diamond stones may also help in this regard, as only the ‘points’ of the diamonds are exposed above the binder matrix.

https://scienceofsharp.com/2019/10/02/g ... ge-part-1/

In this case with K390 in SE, we have an interesting case, as we can’t really use benchstones for reprofiling, and yes, there will be wear on the corners of the CBN/diamond rods from using them in this way. Light pressure would be vital, and even this pressure will be greatly magnified by the tiny contact area.

I personally wouldn’t be racing to reprofile my K390 SE to 15 degrees inclusive. Although the steel is very impressive in thin edges, it’s still run a fair bit harder and has a high carbide volume relative to some of the established ‘high performers’ in SE edges, like H1, VG10, LC200N, CTSBD1, 52100 etc.

When I get my first K390 SE, I think I’ll just use the brown Sharpmaker rods and the Goldenstone/Doublestuff 2 and an Idahone cylindrical ceramic rod to progressively hone the existing serrations as I touch up the edge. This will also round over the spike serrations a bit.

My last Seki SE edge, the LC200N Pac Salt 2 is a fair bit shallower in its grind than the old skool spiky serrations, so hopefully this is an ongoing CQI adaptation on the SE Seki knives.

Haha, thanks for the clarification!

I would imagine it would be a nuisance in the rear to reprofile to 9dps using the SM alone. Not impossible, just might take time which these days is a valuable commodity.

[Brock O Lee]

It will be very easy to strip the diamonds off the corners of the rods due to the increase pressure (psi) when using the corners.

Been there done that... Got the bare corners of the diamond rods to show. :)

I knew about the risk, and was convinced I was using minimal force, but this still happened while trying to reprofile H1 SE.

Honestly, I would not attempt to reprofile a serrated K390 edge with a Sharpmaker. Keep it sharp at the factory angles, yes. Bulk material removal, nope.

[sal]

As suggested, light pressure. let the CBN/Diamond do the cutting. Or if in doubt, just use the corner of the brown stone at 30 degrees until you are happy. I recommend a loupe so you can see what you are doing as you are doing it. Then maybe a 40 degree micro bevel for 2 or 3 strokes.

Your too kind Darby, You're not the only one that likes big serrated exotic steel folders. :p

sal