RSK : S30V (chipping defect)

C

Cliff Stamp

BANNED
Joined
Oct 5, 1998
Messages
17,562
This RSK was a replacement for one which was replaced due to edge damage (chipping) in light use. This one also had the same problem and during a discussion it was offered for an inspection.

The initial edge had chips in several areas and deformed in others. Under magnification the chips were angular in nature with little to no compression which usually results from contacts off of hard objects which confirms the reported behavior of chipping under light use.

The blade was sharpened three times matching the NIB angle (13 degrees), the sharpened was taken down to x-coarse SiC to remove all damage and produce a uniform and very coarse finish. The polish was then raised up through a series of fine stones ending on chromium oxide loaded leather.

The first trial went 200 SiC, 800 AO, 1000 AO, 4000 AO. Under magnification (10x) the edge had chips which were much larger than the 4000 grit scratch lines, similar to the 1000 AO finish. Additional sessions of honing on the 4000 AO didn't help, they just moved around. Only reached ability to slice newsprint.

A quick check cutting some birch hardwood floring showed the obvious result, the edge failed after just a few cuts and was macroscopically damaged and visibly reflecting light. The sharpness was low, could not readily slice newsprint. Optimally the edge should make hundreds of cuts before being so blunted.


Next round the same initial steps were followed by a black arkansas stone after the 1000 AO. This actually damaged the edge visibly. It actually got deformed on the stone and would reflect light in areas after about 30 seconds of honing. A Paramilitary was then swapped in as a control and it responded well to the same hone.

The final round replaced the arkansas stone with a 1200 grit dmt and the honing was feather light, this was followed by some polishing on chromium oxided loaded leather. The edge could almost push cut the newsprint, but under magnification small chips could still be seen and the edge retention on the hardwood was still low. This is the same behavior as seen on the Skirmish from Benchmade reported awhile ago.

In general nice knife design, the edge is both thin (~0.010") and acute (~13 per side). The handle is a little abrasive though fairly nicely shaped for versatility. The clip is squarish, the new Spyderco clips are *much* nicer.

-Cliff
 
That is not good to have two back to back like that is it? I wonder if they just got a bad batch of steel at BM or if it is more likely the heat treatment. It would be interesting to get the blade Rockwell tested to see if maybe it is related to the hardness.

STR
 
Re: S30V chipaholism... I've got a manix and a native, both in S30V, and the native has proven to be quite chip-prone, (MUCH moreso than say, my 881sp, in ats-34, doing the exact same job). I know the grinds are drastically different, but it's kinda got me spooked about S30V, and I've left my manix in its box where it's safe, also it keeps me from ordering a Paramilitary, because I don't want to deal with having to grind out the chips... ON the other hand, that trident knives testing video certainly makes their treatment of S30V look tough. Is my Native's S30V, just unique or has this been other's experiences as well...? How's the Para's edge toughness?
 
I've got two Para Military knives. One plain edge and one with full serrations. While I have not worked the serrated one much I have used the PE a lot and never saw any evidence of a chipping problem. It holds a good edge for a very long time and has impressed me overall with its performance.

This is not the first report of this problem though. I thought that CM had worked out these problems but I guess not. I'm afraid it may cause me to also move S30V down a notch in my rating. I have always liked BG42 and VG 10 just as well so I may have to hug those for a while until we hear more on S30V. Fortunately I only have a few knives in S30V. I would think if I was going to see problems that they would have shown up right away as that seems to be the case.
 
Thanks for the info STR, I'm glad I'm not alone in this... :) As for VG-10 I've got one of those waved endura 4s on reserve, it'll be my first VG-10 User, I've also got an ATR which is being kept mint, so I've no idea how it's going to perform yet, aside from what I've read, which seems favorable...
 
STR said:
That is not good to have two back to back like that is it?
Click to expand...

No, in general there are few people who would tolerate that, just imagine having this type of problem with a brand of sneakers and then reading about how this isn't uncommon. I doubt many people would go back for a third pair especially when there are lots of sneakers without problems. In general the forums tend to expect a much higher tolerance for rejects.

STR said:
I would think if I was going to see problems that they would have shown up right away as that seems to be the case.
Click to expand...

Yes, I have not heard of any problems coming up with use, they go away some times with sharpening which could be due to a number of reasons.

-Cliff
 
I am curious to ask if it is your conclusion at this point, is that S30V itself is the issue, or if it is all leading back to the heat treatment on these that is causing the chipping.

Considering your tests on S30V to date, would it be worth it to try to do a test on a Strider - or is there not enough treatment difference to warrant that in comparison to the others you have tested?
 
Thanks for the testing Cliff.
I have three folders in S30V:- Lone Wolf T2, Spyderco Paramilitary and Spyderco ATR.
After only modest, light use, the ATR edge is just a mess of small chips, especially on the belly of the blade, about 3/4 toward the tip. This is dismaying in a knife so expensive. If I regrind and remove all the chips, it seems likely they will come back again with normal use.
So far the Para & T2 have not given any trouble but I will not take a chance with another knife in S30V until consistency can be established.
 
Cliff, the test you did on the manix and para a wile back seemed to provide better results. Is it the way these two companies process their steel?
 
I have several knives in S30V, including an RSK, and I have not experienced any chipping problems so far. I have used my large Sebenza in S30V extensively, including extended work at reducing large cardboard boxes to strips and I have not seen any chipping. However, the edge retention is no better than my BG-42 Sebenza, no worse either. I have made no attempt to reduce the edge angles on these knives having chosen to maintain the factory angles.

I have one custom in S30V that came from the maker with a wire edge. This edge actually flopped back a forth without tearing or chipping until I used a diamond hone to take it off. Since then it has performed fine and it holds its edge well.

Perhaps what we are seeing is QC issues from various companies as they learn how to make S30V blades. Either that or the PM process lacks uniformity right from CM, and varies from lot to lot. I think the jury is still out on this alloy and we'll have to see how it proceeds from here.

Has anyone had any trouble with the SRKW folder in S30V? I don't have one and I'm curious if SRKW has figured out the heat treat process for this steel.
 
My Skirmish gets "small" chips (I can thumbnail feel them) out of the edge after approximately 10 full sharpenings. I've come to look at it as "serrations," as it still cuts rope, plastic, etc. well.

But the experience, and those of others like Mr. Stamp, has made me less than enthusiastic concerning the steel.
 
http://www.tridentknives.com/images/CPM_S30V_steel_1.jpg

This is a very interesting graphic that shows the toughness vs edge holding capabilities of various steels... I find it misleading though, as for instance, the 3V looks like it should be tougher than wolverine's adamantium, but Cliff beat the crap out of that Fehrman 3v knife with ease, though Cliff's got the mad skillz when it comes to that type of thing. It just goes to show that steel might look great on paper but be much less exciting in the real world, I guess s30v is no exception...
 
Out of the knives I have owned in S30V:
Microtech LCC, chipped edge
Benchmade Skirmish, chipped edge
Spyderco Manix, edge did not chip
Spyderco Lil' Temp, edge did not chip
Spyderco Native, edge did not chip
Microtech UTX70, edge did not chip
Strider SMF, edge did not chip
Strider SnG, edge did not chip.
Seems pretty hit or miss in my experience, although Strider and Spyderco seem to be the best.
 
I have two S30Vs that work fantastically. Been lucky so far. Both from Spyderco (para and dodo). Though the weird blade shape on the dodo might hide microscopic chipping really well since it's nearly impossible to feel on that edge.
 
What was the Rockwell Hardness of the RSK? How about that of the paramilitary? And the Skirmish you also mentioned?
 
My Manix performed well until I gave it to a friend, I'll have to see how he likes it. I have a couple of Buck's that are doing well, but haven't cut anything harder than rope or cardboard yet. I have a $$$ semi-custom that I'd rather not name (and start a flame war) that has been absolute crap. No chipping, but you have to be able to hold an edge to be able to chip. So I can't even get to stage one on that one.

That's what I've seen so far from S30V. I'm going to try to give the Bucks a better workout, they're treated by Bos, and if anyone can get this steel to perform, I would think that he could.

Personally, I'm not at all impressed with this steel so far. BG 42 equals it (for me) in stainless, and is less expensive also. There are plenty of tool steels and high carbon steels that blow it away for edge holding also.
 
I think its a hit and miss thing. You get a good one or you don't. I don't think we can fault BenchMade really. Seems that it is just something about the S30V that just comes up now and then. I guess I've just been lucky so far.

STR
 
My Dominator (S30V) chipped in three places 1" from the tip the first time I used it.

Nice to know I'm not the only one having this problem with S30V, not so nice that it is happening at all.
 
You must log in or register to reply here.
Back
Top