S35VN sharpening issues

[Securis]

That's me

Love your video's on the ramblings of steel! thanks man!

I emailed Shapton regarding the abrasives used in their glass stones. While they did not give me the details, the answer was alumina-based abrasives. Could be Zirconia-toughened alumina.


Miso

Does that mean it won't cut and shape carbides as well as diamond still does? Would it be wrong to guess that the best way to do it would be to shape the carbides with fine diamond and then only polish using alumina?

 

[miso2]

As we discussed in the other thread, they may still cut vanadium carbide but probably at a slower rate than with harder abrasives.

Miso

 

[Obsessed with Edges]

(...)
Does that mean it won't cut and shape carbides as well as diamond still does? Would it be wrong to guess that the best way to do it would be to shape the carbides with fine diamond and then only polish using alumina?

Alumina can remove the carbides by scooping them out of the matrix steel; but it won't cut vanadium carbides themselves, nor will it polish them. If the carbides are small enough in the steels you use (as with most PM-type steels, where VCs are likely below ~4µ in size), you might not care too much about that, depending on how far you take the edge finish. You'll still polish the matrix steel to a point, where the carbides are all that's left influencing the finish. But polishing progress will essentially stop at that point, as will any further refinement of the edge itself.

An eye-opening way to see the difference, is to take a high-vanadium steel like S30V, honed to a finish like DMT's EF (fine satin finish), and then try to polish it to a mirror using alumina-based compounds on a hard strop of wood. Then do the same with a diamond compound at ~3µ or so, on an identical substrate, and see how fast it works and how keen the apex remains, when finished. That's what convinced me, that trying to polish high-VC steels with alumina-based abrasives is essentially counterproductive, in effort and time.

If you arrive at a point where you know you'll need diamond for at least part of the honing or finishing process, following with something less-hard (i.e., alumina) isn't going to produce any additional gains.


David

 

[whp]

Alumina can remove the carbides by scooping them out of the matrix steel; but it won't cut vanadium carbides themselves, nor will it polish them. If the carbides are small enough in the steels you use (as with most PM-type steels, where VCs are likely below ~4µ in size), you might not care too much about that, depending on how far you take the edge finish. You'll still polish the matrix steel to a point, where the carbides are all that's left influencing the finish. But polishing progress will essentially stop at that point, as will any further refinement of the edge itself.

An eye-opening way to see the difference, is to take a high-vanadium steel like S30V, honed to a finish like DMT's EF (fine satin finish), and then try to polish it to a mirror using alumina-based compounds on a hard strop of wood. Then do the same with a diamond compound at ~3µ or so, on an identical substrate, and see how fast it works and how keen the apex remains, when finished. That's what convinced me, that trying to polish high-VC steels with alumina-based abrasives is essentially counterproductive, in effort and time.

If you arrive at a point where you know you'll need diamond for at least part of the honing or finishing process, following with something less-hard (i.e., alumina) isn't going to produce any additional gains.


David

Seems reasonable. Good information.

 

[Securis]

If you arrive at a point where you know you'll need diamond for at least part of the honing or finishing process, following with something less-hard (i.e., alumina) isn't going to produce any additional gains.

David

Will it be detrimental, though, to follow with something less hard like alumina after using diamond.

 

[Obsessed with Edges]

Will it be detrimental, though, to follow with something less hard like alumina after using diamond.

It might be, if taken too far. If it's used basically for cleaning up the edge (burrs, etc), then it wouldn't necessarily be harmful. But, if the goal is simply more polishing, then more likely what you'll get is an edge that'll start rounding off or burnishing a bit, after the alumina has done all it can do with the matrix steel at the edge, but can't do anything to further shape or refine the carbides at the edge. This is always what I've found, when I've tried to use alumina compounds to polish edges on S30V in particular. Sharpness was always a disappointment, even if the bevels might've been additionally polished somewhat.

The 3µ diamond compound I mentioned earlier is what cured all that for me, and it only took a few minutes' work to do it. Difference was night & day, when I tried it on an S30V Kershaw and my Sebenza's S30V blade, after trying for some time to maintain and polish the edges using alumina-based compounds on a wood strop. The diamond left an eye-popping mirror in minutes, with an edge on the Kershaw (Leek) that suddenly compared favorably to the best hair-popping 1095 edge I'd seen.


David

 

[Securis]

It might be, if taken too far. If it's used basically for cleaning up the edge (burrs, etc), then it wouldn't necessarily be harmful. But, if the goal is simply more polishing, then more likely what you'll get is an edge that'll start rounding off or burnishing a bit, after the alumina has done all it can do with the matrix steel at the edge, but can't do anything to further shape or refine the carbides at the edge. This is always what I've found, when I've tried to use alumina compounds to polish edges on S30V in particular. Sharpness was always a disappointment, even if the bevels might've been additionally polished somewhat.

The 3µ diamond compound I mentioned earlier is what cured all that for me, and it only took a few minutes' work to do it. Difference was night & day, when I tried it on an S30V Kershaw and my Sebenza's S30V blade, after trying for some time to maintain and polish the edges using alumina-based compounds on a wood strop. The diamond left an eye-popping mirror in minutes, with an edge on the Kershaw (Leek) that suddenly compared favorably to the best hair-popping 1095 edge I'd seen.


David

That might just be the problem i had this afternoon with M390. I was a bit, overzealous with the polishing tapes from EP and it seemed to be catching at newsprint. I brought them up to about 17 dps (actually 15 on one side, 19 on the other), so i was worried that i was tearing out carbides since there's less steel matrix holding the carbides in.

My attempt tomorrow is to diamond the thing, and touch lightly for awhile on the 3k tapes to let it shine a bit. I should be getting my DMT diamond past tomorrow, i forgot what µ i ordered though.

 

[Securis]

I just got my Diamond Paste from DMT, 3 microns, seems oil based. Did some stropping on an M390 that wasn't really at it's peak. Didn't go through it too much either, but i can feel the noticeable difference in slicing newsprint. Feels smoother with with enough bite to go through newsprint easy. It actually did away with some snags.

 

[miso2]

Hi,

I just finished sharpening my Umnumzaan and want to share the result.

I sharpened it on Edge Pro with #240 and #400 silicon carbide stones (Moldmaster, Congress Tools), lightly deburred on the #600 aluminum oxide Edge Pro stone, and then proceeded to lightly polish with 1 micron diamond suspension deposited on the #2,000 Edge Pro polish tape. Maybe 8 to 10 swipes on each side (full procedures). Diamond suspension was applied on the tape, dried, and I repeated this a couple of times. Regarding the size of diamond, I used 1 micron because I got it free and have not tested larger ones.

I don't know if this is the best way, but it seemed to work, to some extent. I was able to get a refined edge with some toothy bites. It whittles hair nicely and push-cuts tissue paper. Below is a demonstration along side with Spydiechef (LC200N), which takes a very nice edge.

Because the edge is sufficiently refined, it can push cut the soft tissue paper. Yet, it keeps some bites, such that the cut could start in the middle but not from the side of the tissue paper. This is something I have wanted to get but could not have been able to with other abrasives.


Miso

 

[Securis]

Hi,

I just finished sharpening my Umnumzaan and want to share the result.

I sharpened it on Edge Pro with #240 and #400 silicon carbide stones (Moldmaster, Congress Tools), lightly deburred on the #600 aluminum oxide Edge Pro stone, and then proceeded to lightly polish with 1 micron diamond suspension deposited on the #2,000 Edge Pro polish tape. Maybe 8 to 10 swipes on each side (full procedures). Diamond suspension was applied on the tape, dried, and I repeated this a couple of times. Regarding the size of diamond, I used 1 micron because I got it free and have not tested larger ones.

I don't know if this is the best way, but it seemed to work, to some extent. I was able to get a refined edge with some toothy bites. It whittles hair nicely and push-cuts tissue paper. Below is a demonstration along side with Spydiechef (LC200N), which takes a very nice edge.

[Youtube]GwlHmP-N4lE[/Youtube]


Because the edge is sufficiently refined, it can push cut the soft tissue paper. Yet, it keeps some bites, such that the cut could start in the middle but not from the side of the tissue paper. This is something I have wanted to get but could not have been able to with other abrasives.


Miso

Wow, that's a test i gotta try!

I find best results (so far, i haven't reached the sharpness level i'm happy with) with diamond compounds as well. For s35vn, i eventually settled on diamond plate + polish tapes (really lightly, just for aesthetics) and diamond strop.

How do you find LC200N in terms of sharpness/cutting capability and edge retention? i know it's supposed to be very rust resistant, but that's it.

 

[miso2]

Securis,

LC200N takes a very keen edge like VG-10, CTS-XHP, and M390 (when fully polished), and seems to be better in terms of keeping it than VG-10.
I do not have tests for edge retention so cannot tell very much about it.


Miso

 

[Tim the Wizard]

I don't really share the experience of other posters here. OP, I'd be happy to sharpen one of your blades to your specifications for the purpose of comparison.

 

[Securis]

miso2, if and when you do an edge retention test, i'd love to hear about it.

I don't really share the experience of other posters here. OP, I'd be happy to sharpen one of your blades to your specifications for the purpose of comparison.

thanks for the offer, but i am a little ways off to send a knife over. You are right though, there aren't many people around here who bother with the intricacies we are, sadly, where i'm from, people are put off and afraid of things when they get too technical. I embrace it.

 

[Tim the Wizard]

My thoughts when reading your post was that you might try spending more time at lower grits around 120 on the EP. Use a sharpie on the edge and look at it with a 20x loupe under light. Once you can get it to cut paper well at 120 grit only then move on. When I sharpen the vast majority of time is spent getting it right on the first stone.

 

[Father & Son Traditional Sharpening]

I'm inclined to think your India stone is rather glazed as that tends to happen quickly with them if not using them for small contact areas on simple carbon steels with oil as lubricant. This just tends to burnish the edge rather than cutting, which would weaken the steel and possibly lead to failure before you even get off the stone.

I would suggest recutting the surface of the stone and using with oil in the future, also not using it on high carbide steels would probably be advisable... or at least not often without using simpler steels in between to keep cutting aggression high.

 

[Securis]

My thoughts when reading your post was that you might try spending more time at lower grits around 120 on the EP. Use a sharpie on the edge and look at it with a 20x loupe under light. Once you can get it to cut paper well at 120 grit only then move on. When I sharpen the vast majority of time is spent getting it right on the first stone.

I usually pass the blade on the 120/220 just enough times to ensure i get a burr. not a strong burr, but a noticeable one. Would that be sufficient? I don't usually try cutting paper at this point as i know it's gonna be rough. I do, however, ensure that i apex the edge.

I'm inclined to think your India stone is rather glazed as that tends to happen quickly with them if not using them for small contact areas on simple carbon steels with oil as lubricant. This just tends to burnish the edge rather than cutting, which would weaken the steel and possibly lead to failure before you even get off the stone.

I would suggest recutting the surface of the stone and using with oil in the future, also not using it on high carbide steels would probably be advisable... or at least not often without using simpler steels in between to keep cutting aggression high.

You are actually quite right, sir. Up until recently, i would just scrub the stones with scotch brite scouring pad, but then, i watched a few video's stating that abrasives need to release new abrasives to be effective, hence i got a SilC stone to flatten as well as expose new surfaces.

DeadboxHero

If you're still following this thread, i've got a bit of a question regarding shaptons. Since Shaptoms are Alumina based ceremics, and so are the mid and higher grit EP stones, would that mean i'd get the same problems i have with higher carbide steels, in that it won't cut the carbides as well, and end up rounding/burnishing them?

I'm starting to consider buying those 4" DMT stones and just sticking them to my old EP plates, since i'm getting better results with diamond.

 

[miso2]

Just FYI.
You can buy a variety of Edge Pro compatible stones, including diamond, CBN, and silicon carbide stones, from Gritomatic.


Miso

 

[Securis]

Just FYI.
You can buy a variety of Edge Pro compatible stones, including diamond, CBN, and silicon carbide stones, from Gritomatic.


Miso

Man, i saw your post and made the mistake of actually googling Gritomatic. I just spent 70 bucks there... Thanks for the recommendation though. And so this slippery slope gets steeper, eh well, at least my stones have a decent ROI.

 

[miso2]

Wow. That's fast. What did you order? Hold you compulsion!
Another FYI. Silicon carbide coarse stones from Congress Tools (Moldmaster) is well graded here. You would need a stone blank from Edge Pro though.


Miso

 

[Securis]

Wow. That's fast. What did you order? Hold you compulsion!
Another FYI. Silicon carbide coarse stones from Congress Tools (Moldmaster) is well graded here. You would need a stone blank from Edge Pro though.


Miso

got the diamond 1200 and 2000.

Hold my compulsion? you realize where you're typing that right? I lost all self control months ago. I never thought i'd look at a piece of ceramic like this.

That being said, my shaptons, CKTG diamonds, and chosera just arrived. So no more buying till i put em through a couple knives, earn a couple bucks, and spend a couple hundred more. i'm doomed...

https://www.instagram.com/p/BSOf1S7lm6w/?taken-by=securis1911