Thread: Do Natural Stone Have Any limitations as to Steel Type?

I believe I read it on a knife forum that Arkies in particular don't work on some of the newer steels. I think cpm30sv or something like that was mention along with some high carbon stainless. I can believe my beloved Arkies would let me down though it might be slow going. Can any one confirm this? I suppose most razors don't fall into this category and I haven't run across anything that I couldn't handle yet. So far I've only been working with D-2, O-1, 1095, and the Craftsman saw blade I found in the alley that makes wonderful wood carving knives. I can't believe Arkies wouldn't work on darn near anything. Thanks!

You cannot hone your solid gold razors on most stones. Don't worry: I have the proper stones for honing gold so just send them to me.

On a more serious note: you should be able to hone all your razors on most naturals but you may find that a certain razor may like the one hone better than the other.

Natural stones are able to finish most steels but you will not want to try one for setting bevels on some steels. Usually these steels aren't used for razors though. The troublesome steels are those that form vanadium and some other carbides. These carbides are VERY much harder than the abrasives found in most natural stones.

Even though natural stones will put a finished edge on these steels, in my experience the edge won't be as clean as an edge produced with abrasives that are hard enough to cut the carbides. Edge retention will suffer a bit also.

Some jnats cut wear-resistant steel like SLD better than other jnats. You just have to try them.

Same is true of synths too BTW, I was recently comparing a 4k Shapton Glass HR (the white one) to a 5k Shapton Pro and while both cut carbon well and about equal (the HR was a little faster), the HR was noticeably faster on my Yoshikane SLD slicer. That's not surprising, the HR series was designed to cut the Lie-Nielsen stainless plane blade steel.

Cheers, Steve

(Typing with a near year-long migraine now, if I repeat anything, please excuse the inconvenience!)

You can burnish most of the really wear resistant steels with an arkansas stone, but you can't really sharpen them (if that means cutting grooves) or do much grinding. Two things come into play:
1) hardness - somewhere around 61 or 62 hardness steel is the same hardness as the particles in a novaculite stone. If you ever sharpened a cheap pocket knife (that is soft) on an arkansas stone, you will have noticed how even the fine stones want to raise a burr. That's because a differential appears in particle vs. steel hardness and the ark particles cut a lot deeper - you get a sense then that they're not really that small, plus features on the stone (pits, etc) can allow the particles to act as a group and imitate larger particles. high 50s to low 60s is the sweet spot for a good edge.
2) alloy (due to carbides)

The carbides that are not iron carbides (i.e., pretty much everything else) are harder the the arkansas stone/novaculite particles, some of them quite a lot harder.

Use something else for material removal other than arks (actually, the old crystolon stones - well, not the old ones, but new friable ones - old ones get hard and don't do much). You can still apply a final polish with the arks, but for the really difficult stuff, just going straight to a bunch of diamond steps is more practical. Diamond cuts the worst stuff that I've tried - M4 - as if it's nothing spectacular.

Of the abrasion resistant steels, the more evenly distributed the carbides, the better you can do with them. If you can't cut them, you'd at least like for them to be spread out and not too large. You can sometimes cut the matrix that they're in if they are distributed evenly and get a pretty good edge (think powder metallurgy or cryogenically treated steel (henckels friodur). Hardness comes up again - sometimes you get really highly alloyed steels that seem to sharpen fine on natural stones. if they are soft, that explains it. I guess you're working the matrix of metal that's holding the carbides together.

Here's my experience with arks, which are my favorite. Only approached by fine quality japanese naturals, which are expensive (!!!) - three exclamation points expensive, even directly from japan. Hard and soft, then alloy:

* File hard (harder than 62) - too hard even with plain carbon steel, arks just burnish, but the effect can be useful. You can get a beautiful finish on a japanese chisel, but don't expect to sharpen out any damage. The bevel of the chisel would be indistinguishable from one sharpened on jnats. Jigane (soft steel) conditions the ark stone a little bit in a positive way. Too much of steel this hard
* 56-61 or so hardness - ideal
* Saw temper and below - good for general maintenance of some tools (card scrapers, etc), but bad for finishing - think cheap pocket knife

Of properly hardened steels - tool and good quality knife hardness:

Great:
- 1095 - superb
- 01 - very good
- Nickel steel carbon steels (swedish ore, I think) - very good
- White II steel that's not more than 62 hardness - takes a great edge.

OK
- A2 - marginal, but better quality A2 with carbides dispersed well sharpens fine - medium and heavy work has to be done with something else
- 440C - like friodur, good if carbides dispersed.
- VG 10 - seems an awful lot like good 440C
- T-series High speed steel - fine grained for HSS - decent if it's not diamond hard

No Go (unless they are soft, but if they are soft, what's the point - a hard carbon steel will outperform them):
- D2 (not sure what its attraction is, anyway. It's a diemaking steel that was intended to be a cheap replacement for M class high speed steels. Wear resistant with poor ability to hold a sharpened edge, but good ability to work for a while with one that's mildly failed
- S30V - Icy rubber.
- M2 High speed steel - Rubber if fully hardened. You can polish it with an arkansas stone. Cuts if soft (like some turning tools). If it's soft enough to cut easily on arks, suspect it's not hardened very well
- M4 - Not close. Doesn't even like most synthetic stones. Diamonds think it's cotton candy.

Originally Posted by Steve56

Some jnats cut wear-resistant steel like SLD better than other jnats. You just have to try them.

Same is true of synths too BTW, I was recently comparing a 4k Shapton Glass HR (the white one) to a 5k Shapton Pro and while both cut carbon well and about equal (the HR was a little faster), the HR was noticeably faster on my Yoshikane SLD slicer. That's not surprising, the HR series was designed to cut the Lie-Nielsen stainless plane blade steel.

Cheers, Steve

Lie Nielsen uses A2 because (they don't say this - at least not all of it - I just gather it), they can't really harden anything else without warpage and they are in a boutique industry where they want everything super dead flat. Presumably, they run their irons on a surface grinder after everything is done and want them to be dead flat (or if they don't, they want a steel that they wouldn't have to run on a surface grinder). They tried W1 type steel and the O1. O1 behaves very well, but not perfectly. A2 is better behaved than most (warps less) and not too expensive. W1 is difficult - they could only harden part of the iron when they were using it (any more and warpage was too bad), and left a fair amount unhardened presuming that most users would never use enough of the iron to be able to tell. Some of their planes were sold to historic trades users at Williamsburg and the toolmaker there found out the irons weren't fully hardened when the people who actually use planes a lot in those trades went through the first inch of the irons. LN confirmed it. That toolmaker suggested A2 to them, but at the time they declined his advice (I don't know how they came upon it later, unless someone else suggested it - they may have gotten that suggestion from more than one). I'm sure the A2 irons are fully hardened -Lie Nielsen does them better than anyone else (my subjectivity). It was ultimately a good move for them given their needs and the fact that almost all of their customers use synthetic stones. We don't see the manufacturing side of things and the demands there, but I'm sure they are significant and affect what makers offer.

Shapton's ad copy stuff said jargon about HR, but I couldn't tell any difference between the glasstone types, and the shapton pros cut A2 fine. So does just about everything synthetic. I really couldn't figure that whole thing out, and they were very expensive for what they are (still are). I wish shapton would just put glass under the pro series if they wanted to put glass under a stone. It would make the pro stones usable to the last mm, and you'd get 3 times as much abrasive. For razors, wear doesn't matter, but for tools, the 1k pro doesn't last long. They expect you to replace it as a consumable, but that's annoying.

Your being able to tell the HR may have to do with what you're sharpening (knives) vs. me (tools). I think the abrasives are functionally similar, but the binder may be different for some stones. I do recall ordering a stone and telling a dealer in japan what the part number was - I recall some oddity about them. Maybe that the dealers couldn't get the HR stones in Japan? At any rate, the part number for that particular grit was the same for both types of stones.

DaveW, I'm blown away! That's exactly what I was looking for! Do I dare ask how you found all of this out? Thank you.

Originally Posted by duke762

DaveW, I'm blown away! That's exactly what I was looking for! Do I dare ask how you found all of this out? Thank you.

Wasting money on things I didn't need, I guess!!! I get fixated on odd things.