Lil Timmy said:
S90V is supposed to be VERY hard to resharpen, I think that's why most people prefer to use S30V instead.
That was indeed one of the selling points of S30V, of course this isn't a problem if the maker knows how to use the steel. I sharpen full hard steels all the time, including high alloy ones like M2. With an edge geometry optomized for the steel, and the steel a sensible one for the use of the knife, sharpening isn't a concern.
digdeep said:
Cliff, have you actually seen D2 shatter into pieces and if so may I ask what knife it was?
I have used it mainly in smaller blades and it breaks easily with no flex, like the tip on the Dozier Agent, and the edges chip with little to no deformation.
It isn't hard to find a maker who will describe D2 in this manner, Mel Sorg used to run D2 in small blades and 5160 in large blades for this reason. It is one of the more brittle tool steels.
Dozier and Wilson are others who are very clear about the low toughness of D2, Busse used to make large blades out of D2 when he started and is fairly open now he would not make anything tactical out of it.
Its low ductility and impact toughness are also well known, Bryson's book is of particular benefit here as it shows the grain structure and large aggregated carbides of D2.
To be clear though, D2 isn't really worse than most high carbon stainless in this regard, I have seen VG-10 shatter into pieces in a Deerhunter, and have seen many S30V blades break into pieces when flexed, and one literally explode into fragments.
A lot comes of the geometry as well, a nice slim blade with a convex grind like I have on my Mel Sorg utility hunter would be far less likely to fragment than a square spined, hollow sabre ground, 1/4" tactical.
Would a specific heat treatment employed on D2 reduce this characteristic?
Swamp Rat is getting decent performance out of D2 in this regard with a full cryo among other things and their blades are significantly tougher than a lot of other D2 I have seen, though still not something I would want in a large blade, they are pretty clear though it is a large step down from SR101 in regards to impact toughness.
Of course it isn't hard to find a maker who will say D2 is all kinds of tough, but then again you can find makers that will say that about any steel. Look at the ones which will actually describe steels as brittle and do impact and flex work and see how many of them will promote D2 as being tough.
And of course for those that do promote it (or any other steel) as being so tough, ask for performance specifications specifically and then ask if you can duplicate them on one of thier knives. That usually ends the hype.
Knifeclerk said:
I've found that S90V can't take as fine an edge as S30V.
The machinability is way lower so it will take far longer to sharpen, it is one of the steels which really needs use of micro-bevels for efficient sharpening. When this is done sharpening is pretty much independent of steel type anyway, anything is ground easily on coarse hones and everything responds to a micro-bevel near instantly.
Chuck Bybee said:
Who marketed S30V this way?
Everyone, yes including Crucible, in fact if you read the orange book that they produce they make a huge deal out of the vanadium percentage and how (and rightly so) you can almost simply argue wear resistance by vanadium percentage in some steels, plus S90V can be ran harder so it hits S30V twice.
I just rechecked the spec sheets and Crucible is still clear on S90V having several times over the wear resistance of S30V at similar toughness levels, it just isn't really stated a obviously as it was a half a dozen years ago, but you can find it if you look for it.
It was always clear it was a step down in edge holding from S90V, the arguement was that it would be easier to make and finish and easier for the customer to maintain, never that it was a superior choice for edge retention. Wilson is pretty clear about this directly as were other makers in the beginning before the S30V hype engine exploded.
In the beginning (I first discussed it with Wilsion in Oct. of 1999), it was clear it was a step down from S90V. He was looking at it for a way to move up from ATS-34 without going all the way to S90V. It wasn't replacing his S90V knives, just an intermediate step, a way to introduce people to crucible steels without having to deal with S90V.
Even now you will see S30V promoted at D2 levels in terms of edge retention, and just having a slight lead over 154CM (20%), S90V was (and still is) promoted far beyond this, they are just not directly compared to each other anymore.
When it was first being developed by custom makers it was, because many were using S90V and thus it was obvious that people would ask about the two. Simonich even did a few test runs and posted them on the forums, and S30V as would be obvious was behind S90V in edge retention, it would be pretty odd to argue otherwise.
As an example :
Here is one of the comments I was referencing :
"Very nice to heat treat . Easy to get 61 (seems to be the best hardness to use) with 1970 austentizing and 400 temper. With an air quench. I haven't tried oil quench yet . With 2000 quench I can pick up about 1 pt hardness with Sub Zero with a final as quenched of 63. AT 1950 no apparent increase in hardness out of the LN2. Grinds in the hardened state a little easier than S-60V. A dream compared to 90V or 10V. Difficult to get a good 400-600 grit belt finish. I just hand rub them to a satin finish from 240 grit and again takes about half the time as S-90V. Steel cost is more than 154CM but about half of S-90V. Good corrosion resistance. Can cut up a grapefruit and leave the knife on the board overnight and no corrosion evident, but the blade is duller. Same as 90V in that regard. It seems to be tougher than 154CM , but probably not at the A2 category . It is the best stainless I have worked with so far for toughness. (based on one Fillet knife and one semi) Edge holding is a little letter better than S60V at R 57, but not in the S-90V or 10V category-- to be expected not a surprise here."
That was Wilson about four years ago, a couple of years later the perspective on the steel had degenerated horribly due to the hype engine, and S30V was now difficult to grind, impossible to harden above 58/59 even with cryo, and the toughness claims kept growing and growing, and S90V was long forgotton.
Note the specific details Wilson gives, he is one of the most straightforward makers around in this respect, he behaves as if he had no monetary connection to the industry at all. Then again he does work as an engineer as well, which probably makes a large difference, but it seems more character than anything.
-Cliff
