s30v woes

[Cliff Stamp]

I asked recently on BF if anyone had a chipped RSK of any type that had been returned to either Doug Ritter / Aeromedix or Benchmade; no answer.

It isn't unreasonable to assume that everyone who has problems has seen the question, I compiled just a short list of problems with S30V knives awhile ago, it isn't isolated incidents nor are they abuse. I also have used a RSK which was returned due to chipping and the replacement was defective in the same way.

-Cliff

 

[Dog of War]

I'm finding it next to impossible to raise a bur on the blade while sharpening, so I'm kind of as a loss here.

I'm not sure if the problem here is the s30v blade itself, or the factory grind on the blade that is causing me such difficulty.

I'm going to assume you're getting all the way to the edge with your sharpening. Of course if you're not - easy to do working freehand with a low machinability steel like S30V - well that could be the problem right there.

My suggestion is, for $10 you can buy a nice little microscope from Radio Shack which is really invaluable for checking edges on all your knives and identifying problems. I've had problems with S30V microchipping and without a microscope all I could tell was that the knives didn't want to take a very good edge, or would lose it quickly. You could also be getting a burr that's so small you can't detect it easily, microscope will let you see it. Or it could be that you're just trying to sharpen the edge too thin .... using the 'scope you can quickly tell if making the edge bevel a little wider, or adding a microbevel, solves the problem.

FWIW there have been some problems with brittleness reported with Kershaw's S30V, but they seem to be good about making replacements. Knifemaker Phil Wilson has posted that heat treatment of S30V requires a degree of precision and control that could be a problem for large production batches, I think that could explain the frequency of chipping and brittleness we see with this steel.

 

[Active Verb]

Burr ? Whats a burr ?

http://en.wikipedia.org/wiki/Aaron_burr

 

[Wunderbar]

I too have had a hard time sharpening S30V. No chipping though. My S30V knives are Microtech UMS's. I don't think the edges are ground too thin. Hence the lack of chipping. I really prefer 154CM.

 

[mete]

Active Verb, that's the Burr I'm familiar with !! Since I've been sharpening knives and other tools for over 50 years I think I know something about the subject .I don't have problems sharpening regardless of the tool , I do it quickly and easily .And in all those years I've never used blades to shave my arms !!!! And I never use 'systems' or fixtures !

 

[SteelDriver]

A note of observation, a while back I forgot to double temper a S30v blade and as result It had some of the chipping problems that many have noticed. I wonder if some manufactures are trying to cut cost and only tempering once

Leon,

I recall a Crucible rep mentioning that he discovered one manufacturer single tempering S30V back when production companies began adding S30V to their lineups. A number of "early" S30V knives might be single tempered. Hopefully as time goes on, manufacturers will learn how to properly HT and process S30V so these reports of chipping will become less frequent.

 

[Cliff Stamp]

Multiple tempering is more critical for upper temperatures because there is significant transformation of the austensite to martensite because of carbide precipitation which effects the Ms point and thus induces martensite to form in the cooling after tempering. A single temper then leaves this martensite untempered. However S30V is usually tempered very low around 350F - 400F which doesn't have the same effect on the steel. Nor in general are the results so drastic to explain the performance seen such as steels chipping on carboard, plastic, vegetation, etc. . No one would argue that going from single to double temper, especially with low temperatures would induce such a change in the material properties of the steel.

-Cliff

 

[rev_jch]

Usually the problem with sharpening S30V, is that most do not understand you cannot sharpen it to a low (fine) angle. That will cause the blade to become brittle and cause chipping.

The angle (you sharpen at) on the newer high end steels do make a difference!

 

[HoB]

You can sharpen S30V with arkansas stones, you can even sharpen it with cheap dollar stones you find at hardware stores. Only 4% of S30V is vanadium carbide and the rest of it is butter soft compared to sharpening stones. I detailed the responce of a bunch of cheap abrasives on Wilson's S30V South Fork.


-Cliff

I understand, but some claim that the carbides are not cut but pulled out of the edge with a soft abrasive. I am sitting on the fence whether I am believing this or not. I know for sure that a normal waterstone has no problem sharpening S30V.

As you know, cheap doesn't mean soft. Most cheap dollar stones are these days AFAIK SiC, and therefore MUCH harder than Novaculite. With the exception of diamond, I doubt that you pay much these days for the actual abrasive in a stone. I would guess that you pay mostly for the grading of the abrasive and for the binder.

 

[Cliff Stamp]

Usually the problem with sharpening S30V, is that most do not understand you cannot sharpen it to a low (fine) angle. That will cause the blade to become brittle and cause chipping.

It is true that high carbide, and especially stainless, steel do require more obtuse angles for stability, however people are seeing lower stability in S30V than in VG-10 or D2 which should not be the case. A lot of the problems are also reported on the initial edges, not after people have reduced the edge angles as well.

I understand, but some claim that the carbides are not cut but pulled out of the edge with a soft abrasive.

The big clumpy carbides are the chromium ones, these are usually what cause chipping issues, the alloy ones are much smaller. Thus if this was an issue you would see it very wide spread. The chroimum carbides in 440A for example are much bigger than in S30V and thus if tear out was a problem in S30V it would be extreme in the 440 series. In general I have not found this to be an issue but keep meaning to look at it again in detail with 10V. There has been some work done by Elliot in regards to the high vanadium steels requiring diamond for optimal sharpness but he is speaking of a difference that most people would never see.

-Cliff

 

[SteelDriver]

However S30V is usually tempered very low around 350F - 400F which doesn't have the same effect on the steel.

Where are you getting this from? Crucible gives 400-750°F as the tempering range and 600°F as the recommended temperature. Paul Bos usually tempers S30V at 625-650°F plus cryo to get 59.5-60 HRC, so Strider and Buck probably follow likewise. Do you know which makers are tempering at 350-400°F and why?

 

[Cliff Stamp]

Paul Bos usually tempers S30V at 625-650°F plus cryo to get 59.5-60 HRC, so Strider and Buck probably follow likewise.

Tempered at 650F, even with old+cold you are not getting 60 HRC unless you are austenizing above 2000F and the steel was designed to be austenized at 1950 which gives 58 HRC with that temper, ref. Crucible's data sheet.

Do you know which makers are tempering at 350-400°F and why?

Wilson, because he found it works better there, this is with a 2040 austenization which is higher than most will run. High temper draws on high carbide steels generally are not a good idea because this weakens the steel and thus the edge becomes more prone to rolling and the edge stability is directly lowered.

However even at those moderate temperatures of ~600F you are still not getting a drastic second temper responce so that would not explain the issues being seen. Yes you should always multiple temper on the complex steels, but the effect isn't that strong.

-Cliff

 

[destroythealter]

After skimming through the posts I saw a few people recomending stropping. A little more than a week ago I was sharpening s30v and after finishing with the SS maker I found the knife sharp but not really sharp or scary sharp. After passing it over the strop a bunch of times I tested it and found it to be EXTREMELY sharp. I can't tell you exactly why in that particular case (stropping seemed to do a lot more than usual) but if you haven't already done so, that's what I'd recomend.

I've had only good experiences with S30V and would say it is unlikely that the heat treat is to blame however, it is one of the more challenging steels to sharpen.

 

[SteelDriver]

Tempered at 650F, even with old+cold you are not getting 60 HRC unless you are austenizing above 2000F and the steel was designed to be austenized at 1950 which gives 58 HRC with that temper, ref. Crucible's data sheet.

Paul austenitizes S30V at 1950°F, last I heard. You can ask him how he gets close to 60 HRC with his schedule. You mentioned that S30V is usually tempered at 350-400°F. Who else besides Wilson is tempering in this range?

However even at those moderate temperatures of ~600F you are still not getting a drastic second temper responce so that would not explain the issues being seen. Yes you should always multiple temper on the complex steels, but the effect isn't that strong.

Perhaps Leon could tell us more about the chipping he experienced with a single temper, as well as what temperature he's using.

 

[Cliff Stamp]

You mentioned that S30V is usually tempered at 350-400°F. Who else besides Wilson is tempering in this range?

I assumed most because they all claim HRC's which would require those temperatures according to Crucible as I noted previously unless their spec sheet if off. But according to your data many run slightly higher, however 600F is still a low temperature temper, so the origional point holds, 950+ is a high temper. Note further if you use cold treatments you reduce the need for double tempering because you have already made a great step in minimizing retained austenite with the cold. Generally you only need multiple tempers with cold treatments on HSS or similar high alloy steels because the austenite in them tends to be really stable and not even cold treatments will minimize it and thus you need the multiple high tempers to do so.

-Cliff

 

[riddleofsteel]

My EDC knive is a Ritter Grip in S30V. I am used to sharpening steels like VG10 in a Falkniven and I have access to diamond hones, charged leather hones, steels and a variety of stones.
I sue my S30V blade form general box cutting, string, plastic straps, wood carving, skinning animals, cutting bait ect. All the advanced metalurgy discussed here aside my only big complaint is that the blade discolors fast even though I clean it regularly.
As soon as the knife shows signs of dulling, which is not often, I touch it up on a Schrade Honesteel. After that I hone it on a flat bed leather hone charged with chromium oxide. The resulting polished edge is scary sharp. My main problem is cutting myself.
As a matter of fact I often skip the polishing process and leave a honesteel edge on this knife. It is more than enough to cut anything I need, stays sharp longer and I can feel when I am cutting myself.

LOL

 

[leon.pugh]

I double quench at 2000 with frozen aluminum quench plates. Double temper at 400, overnight pack in dry ice i between, three hours each temper, I have not done any elaborate testing, butt the double quench does get the steel a little harder. I profile the blade with a 220 DMT diamond, then refine that with a 320, Then a 1200 to level the high spots, leaving some course scratches. I try to achieve a semi-convex angle of about 15 deg. This is what I due for hunting knives that cut mostly skin, hair & flesh. Before I install the scales on my knives I take them to work for few days where they take a beating, cutting rubber, plastic, paper, old hardened radiator hoses etc. The onley knife that did not perform was the one I forgot to double temper. HAS ANYONE ELSE UTILIZED DOUBLE QUENCHING HIGH END STEELS ??

Leon Pugh

 

[leon.pugh]

Did you get my replie e mail. I need knife specs. from you, style, steel, size, scales etc. example photos would be good.

 

[JD Spydo]

I find S30V, 440V and 2 of Crucible's other blade steels a chore to sharpen. It's funny though because I even find their older 440V ( S-60V) to even be a lot meaner to sharpen than S-30V. First of all I am somewhat of a fan of high grade Arkansas stones but I agree with HOB that most of the novaculite is not hard enough to abrade most of the newer tool steels or high vanadium steels out on the market presently.

First of all I think you should resign yourself to use either Spyderco's ceramic sharpening stones or go with a high quality diamond sharpening stones/equipment. Because S-30V is some really tough stuff to abrade. You could use a high grade of Arkansas Novaculite to do the finishing work with but make sure it's either the Real McCoy translucent grade or the old "Blue-Black" ARkansas stone. Any blade steel that Crucible makes is serious material and takes really high quality sharpening equipment to tackle it.

If you need any more tips feel free to PM me. Good Luck

 

[Andrew Taylor]

I saved this post as I have a couple of S30V blades of Kershaws. This information is from the guy that sharpens Kershaw knives at Kershaw.

CRAIG GREEN
Gold Member Join Date: Feb 2000
Location: Sherwood, Oregon
Posts: 14

Guys,

OK - let me try to answer some questions.

Sharpening at Kershaw - All Kershaw's are sharpened by hand. We use a two step process.

Step 1 - set the cutting edge - for this we use a Silicon Carbide wheel - Noritake - Special hardness and Grit

Step 2 - We hone the cutting edge - usually from one side only (Back side). For this we use a special wheel that I import from Japan

ZDP Leek Primary bevel thickness / angle issue:

The standard 440A leek is hollow ground (Concave) and is .018"-.021" before sharpening.

The ZDP Leek was Flat ground and was .022"-.025" before sharpening.

Did we grind the blades thicker because of chipping / breakage concerns - YES, the Leek blade - due to design has a delicate point and grinding them slightly thicker helps with cutting edge and tip strength.

Does the more obtuse sharpening angle make the apparent sharpeness less than the standard "scary" sharp Leek - IMHO - YES but I don't see us making "Butter" knives either- sharpness is relative.

That said - If you send you ZDP Leek to my attention - I will get it "Scary" sharp and send it right back.

I don't post on the Forum alot - but I do read your posts and take your input to heart - we appreciate the time you take to give us the "Good, Bad and Ugly" on our products.

Craig Green
Factory Manager
Kershaw Knives.