Stones for PM edc folders

[mspelle]

Hi all,
My first post so first a little about my me and my knives and stones.

I am a home cook relatively new to the J knives you find here. I own 210’s Anryu blue hammered, Yuki, Makoto ryusei, Watanabe carbon. Also a Kanehiro bunka and a Kanehiro 240 ginsan. Plus the assorted Shuns,Wustofs,Zwilling/Henckels
When I got these knives and realized how amazingly incredible they are I realized I needed to get better at sharpening.
Now I’m not very good with any sort of fine motor skill work or handyman work and therefore was apprehensive about investing in stones. So I went with the set here with the Bester or Beston 500,1200 and 5000 Rika. And what do you know, I can get knives really sharp using that set up. However, here’s where my question comes in, I also am a folding knife/edc nut and I have these hard PM steels like cpm s35vn, Zdp 189 ,cpm 20cv that I can get sharp using those stones, but man it takes a while to get there!
What stones do you recommend for hard pm steels? Or is that just what it is with them?
Oh, I also just ordered a Shapton glass 500 and a sp 2000k
And just so you know I use my folders! I don’t abuse them but they get heavy daily use at work.

Thank you,
Mike

[slickmamba]

Hey, welcome! I've thought about getting a folder recently since lots of my friends have EDCs, but don't know much about em. you have a solid collection going already.

The shapton glass will definitely do the job, same with the choseras and shapton pros, all of which are hard stones, and cut quickly. I've only used the bester 1000, and remember it being on the softer side and didn't cut super fast, same with the rika 5k. They will do the job with harder steels, but will take longer. There are others who know alot more than me, but those are the ones I've noticed are hard and cut well.

[Ourorboros]

Diamond plates, followed by stropping if you want it that fine.

[lsboogy]

I have powder metal knives (HAP40, CPM, ZDP stuff) in both kitchen and pocket blades. They just take a little longer to sharpen - I sharpened my Spyderco ZDP knife this weekend on a Nubatama 1200 bamboo, Nubatama platinum 6K, and the stropped it. Very nice edge - shaved a coworkers arm in demonstration at lunch today.

[jmcnelly85]

I took an s90v knife to a kohetsu 800 and 2k and was very happy with the results. Your glass stones should work fine, if you are having difficulty try bridging the gap with a 1k.

[lsboogy]

Any aluminum oxide or magnesium oxide powder is much much harder than the hardest steel. Al996 (coorstec) when fired properly has HRC of >110. Ceramics can get much harder than any steel - it may take longer to sharpen a hard steel, but that's life. Even Belgian blue and Arkansas stones (novaculite) are harder than any steel you have ever seen. My soft natural stones sharpen 65HRC steel well, takes longer, but works

[Cigarguy]

I have more backpacking/hunting/outdoor knives with PM steel than kitchen knives with good steel. As others have said it's not any harder to sharpen but takes longer due to the steel being harder. Depending on the knife, some are harder than others due to the profile and/or thumbstud but generally they are fairly straight forward.

For the longest time, until I got my technique down, it was difficult for me to sharpen anything. Besides pressure and angle, the other technique I learned that helped is to go down to a lower grit then work back up. On one particular ZDP folder I had a hard time getting a razor sharp edge because I was using 1000, 3000, 8000 then a fine strop. I got much better result starting with 400 and spending time to properly set the bevel and ensure a proper sharpened blade before moving up. I would guess that at least 70% of my sharpening is on the 400 grit. Once I get this right it is a breeze going to 1000, 3000, 8000, and a fine strop finish. This technique is applicable to any other knives, chisels or edge that I have. I stop at 3000 for most blades as a prefer a razor sharp yet practical edge.

I've heard it many times on this and other forums that it's not the stones, it's the sharpener. I believe it.

[ken123]

Great first post, Mike.

So as you have seen some stones cut very slowly. They have low abrasive concentration. Kings are a prime example - tolerable on white steel, poor on more abrasion resistant steels. Try putting an edge on a ceramic knife with a King. It will simply dull the blade and you won't get a working edge. If you take a long time sharpening a good steel blade with a weak stone you are using too many strokes and will round off your edges. What to do?

Next post ...
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Ken

[nakneker]

I’ve been using Shapton glass stones with my edge pro for S30V, I have a few spydercos and customs with that steel. I’m getting good results with those stones. I free hand my kitchen knives but I am not very good free handing the short curvy blades. Thus the EP.

[ken123]

Obviously a better stone is one choice It should have a better abrasive, better formulation etc. Im a big fan of the Nubatama Platinum series from 320 600 1000 1500 2000 3000 and 6000 grit. I'm working on a 220 to add to the series that I'm excited about. These stones cut quite well through most steels used in pocket knives and kitchen knives. The abrasive in these stones is specifically designed for 'high alloy' steels.

Other good stones include the glassstones - originally designed for plane blades using d2 steel. A good second choice.

For more abrasion resistant steels - even d2 and cpm d2, d3 etc the solution is using a HARDER abrasive - CBN, poly diamond etc. The mohs hardness values are greater - hard enough to cut through the carbides in these abrasion resistant steels.

You can use these abrasives on a strop OR you can put it on a waterstone!

An impressive demonstration is to put a drop of cbn in the slurry on a glassstone. You can HEAR the difference and see the improved result. I use a 1k glassstone and 16 micron cbn. It is impressive.

---
Ken

[lsboogy]

Obviously a better stone is one choice It should have a better abrasive, better formulation etc. Im a big fan of the Nubatama Platinum series from 320 600 1000 1500 2000 3000 and 6000 grit. I'm working on a 220 to add to the series that I'm excited about. These stones cut quite well through most steels used in pocket knives and kitchen knives. The abrasive in these stones is specifically designed for 'high alloy' steels.

Other good stones include the glassstones - originally designed for plane blades using d2 steel. A good second choice.

For more abrasion resistant steels - even d2 and cpm d2, d3 etc the solution is using a HARDER abrasive - CBN, poly diamond etc. The mohs hardness values are greater - hard enough to cut through the carbides in these abrasion resistant steels.

You can use these abrasives on a strop OR you can put it on a waterstone!

An impressive demonstration is to put a drop of cbn in the slurry on a glassstone. You can HEAR the difference and see the improved result. I use a 1k glassstone and 16 micron cbn. It is impressive.

---
Ken

+1
My Nubatama platinum 6K has about the tightest grain variation (<1um as measured on a SEM) of any stone in my kit (dozens of stones - not to Ken's situation, but more than many). Nubatama platinum stones are great - quick work of even CPM and HAP40 steels - softer than a shapton glass but seem to cut quicker - maybe just my take, but I far prefer the JNats and Nubatama platinum stuff to Shapton - I like soft stones with mud - and a soft done with mud I'll sharpen any steel

[lsboogy]

Obviously a better stone is one choice It should have a better abrasive, better formulation etc. Im a big fan of the Nubatama Platinum series from 320 600 1000 1500 2000 3000 and 6000 grit. I'm working on a 220 to add to the series that I'm excited about. These stones cut quite well through most steels used in pocket knives and kitchen knives. The abrasive in these stones is specifically designed for 'high alloy' steels.

Other good stones include the glassstones - originally designed for plane blades using d2 steel. A good second choice.

For more abrasion resistant steels - even d2 and cpm d2, d3 etc the solution is using a HARDER abrasive - CBN, poly diamond etc. The mohs hardness values are greater - hard enough to cut through the carbides in these abrasion resistant steels.

You can use these abrasives on a strop OR you can put it on a waterstone!

An impressive demonstration is to put a drop of cbn in the slurry on a glassstone. You can HEAR the difference and see the improved result. I use a 1k glassstone and 16 micron cbn. It is impressive.

---
Ken

+1
My Nubatama platinum 6K has about the tightest grain variation (<1um as measured on a SEM) of any stone in my kit (dozens of stones - not to Ken's situation, but more than many). Nubatama platinum stones are great - quick work of even CPM and HAP40 steels - softer than a shapton glass but seem to cut quicker - maybe just my take, but I far prefer the JNats and Nubatama platinum stuff to Shapton - I like soft stones with mud - and a soft done with mud will sharpen any steel

[mspelle]

Great first post, Mike.

So as you have seen some stones cut very slowly. They have low abrasive concentration. Kings are a prime example - tolerable on white steel, poor on more abrasion resistant steels. Try putting an edge on a ceramic knife with a King. It will simply dull the blade and you won't get a working edge. If you take a long time sharpening a good steel blade with a weak stone you are using too many strokes and will round off your edges. What to do?

Next post ...
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Ken

Hi Ken,

I just had to lol at you saying if you take a long time sharpening good steel with a weak stone you are using too many strokes.
That’s basically what prompted my post. I was like what’s going on here? I knew but didn’t know ( if you know what I mean) you just made it clear. I was rounding the edge. My J knives for the most part are relatively easy to sharpen so I guess I thought my folders would be easy as well. Always learning; it’s a good thing.

Mike

[mspelle]

Oh and another post to thank you all for your input and advice.
It’s easy to research but sometimes you just need to ask questions and the knowledge from all you on this board is incredible and helpful. So thank you.

Mike

[lsboogy]

Ken is the answer - soft stones take longer, but feedback is better for me. I can feel what's going on and am used to things. Call him and talk to him for a while - he knows what I like and how I sharpen things. I have him on speed dial

[Jason B.]

Diamond or CBN, any abrasive short of that will only yield ok results at best. Even the Shapton Glass stones fall short when dealing with PM steels that have 4% or greater Vanadium content.

[ken123]

Diamond or CBN, any abrasive short of that will only yield ok results at best. Even the Shapton Glass stones fall short when dealing with PM steels that have 4% or greater Vanadium content.

+1 well stated! I prefer compounds on strops or stones over films (too delicate). I like to pick compounds - poly diamond or cbn - that match the stone's grit on synthetic stones and go finer on natural stones. So for instance using 16 micron cbn or poly on a 1k stone, 8 micron on a 2k stone or half micron on a 30k stone, etc. For strops just select the grit you want from 80 microns down to tenth micron or finer. 4% vanadium is a good cutoff point.

---
Ken

[RonAZ]

I have several PM steel edc and an addiction to the old Spyderco Mule knives in different steels. I've used Shapton stones on high carbide steels up to 10V and Maxamet, they work but sprays make a difference. Some years ago Ken opened my eyes on using diamond and CBN sprays on stones for difficult steels, they really help. For touchup on all my knives, regardless of steel, I just use a series of strops with CBN/Diamond sprays.
Ron

[mspelle]

Diamond or CBN, any abrasive short of that will only yield ok results at best. Even the Shapton Glass stones fall short when dealing with PM steels that have 4% or greater Vanadium content.

+1 well stated! I prefer compounds on strops or stones over films (too delicate). I like to pick compounds - poly diamond or cbn - that match the stone's grit on synthetic stones and go finer on natural stones. So for instance using 16 micron cbn or poly on a 1k stone, 8 micron on a 2k stone or half micron on a 30k stone, etc. For strops just select the grit you want from 80 microns down to tenth micron or finer. 4% vanadium is a good cutoff point.

---
Ken

Interesting. I do use strops, a balsa and a leather both with diamond paste 1 and .5. They do make a noticeable difference on the PM steels. And they are awesome for stropping my J knives.

The Shapton 500 and 2000 give better results, they are nice stones I like them, but there is more to be had. So I’m gonna go with the cbn on stones.

Probably use a whole different set for my PM folders.I mean I knew different steels would sharpen differently but I guess I thought they would all just sharpen. Boom! Hah. More research on steels. Learn the craft. Lol-Maybe you’ll catch me sharpening knives at the Farmers Market in a few years when I “retire”.

Thank you all again for the input and advice. I appreciate it.

Mike

[Jason B.]

When dealing with PM folders I stick to my Coarse and Fine DMT, high V PM steels perform at their best with a nice toothy edge.

A little tip, I keep a UF Spyderco ceramic handy and it's nice to have for stubborn burr removal. The Ceramic doesn't do much to the high V steels but helps knock down the stubborn burr if used gently.