Question about fragility in D2 blades

L

Leandroc

Joined
Feb 21, 2007
Messages
55
Hello,
I'd like to ask for more experienced people: is there serious experience that shows D2 is a more fragile steel than for example 1095??
Particulary in RAT knives, did you suffer problems of fragility with D2?
I'll be grateful if you can help me with your experience,
Thank you!!
 
Hi,

I've got a Queen D2 Whittler, no problems with it being fragile. D2 steel was developed as a hot work die steel for things like drop forging dies. Pretty tough stuff.

All things being equal, like sectional thickness, shape, and hardness, D2 would be tougher than plain high carbon 1095 for certain applications.

dalee
 
D2 is very tough, the only thing I would not do is side load it, it could snap. All the stories you hear about D2 are usually false.
 
I know I must've side-loaded my Paramilitary a few times and still the blade's fine. I am more cautious about my S30V blades than my D2 ones.
 
Thank you guys, I've seen a video of a breakage of a RAT7 in D2, it's my favorite knife for survival/bushcraft and I supposed those histories could be true.
One broken knife sometimes means nothing, and I'll continue depending on my RAT knives in D2.
 
The harder a steel is, the more likely it will break. If your Rc hardness is 58-60 in D2, you'll probably be ok. Anything past an Rc hardness of 62 might be pushing it. I have several tools in D2 that are hardened to 64 and they broke when dropped on a concrete floor. :(
 
It will resist deformation better than 1095 (in terms of blunting or edge rolling), but has low ductility/flexibility which means that when its strength has been overcome it will be more likely to break than bend. Pocketknives with blades at 1/16" thickness are going to be more flexible regardless of what they're made out of, but it doesn't change the nature of the steel. The edges are much more likely to chip than the simple carbon steels and "softer" stainless steels found in most pocketknives. I had a custom scout knife made from D2 several years ago and snapped the awl off about 1/3 the way down trying to pop a big stone out of my truck tire. Having often done similar things with the awls (which I use just as a general digging and lifting tool to spare the blade) on $30 SAKs, I don't feel this was beyond the reasonable capabilities of a pocketknife, I just didn't understand the nature of D2 back then.

It makes a great slicing tool, it's just not "tough" in the same sense that the 10XX series (especially 1084 and below) are, or anywhere close to 5160 or L6. It's not that you can't make a tough knife out of it, but you're going to do it by either running it softer--which robs it of its notable deformation resistance--or by going thicker with the geometry and lessening cutting ability. Easier to just use a steel that is better at the applications you're intending it for. For an analogy, you could absolutely take a corvette, add some weight to the rear, beef up the chassis and set up the transmission for low-rpm torque and turn it into a reasonable towing machine. But why do that when there are perfectly good trucks available?

On the other hand, I don't care who made it, a 5160 skinning knife will never keep up with a D2 skinner that's been heat treated properly.

I LOVE D2---give me that over S30V any day of the week. Personal preference, but being good for the same range of tasks, I like how D2 behaves more. It's a great cutlery steel, you just have to match the capabilities to the job.
 
Great post, t1mpani. In my experience though, S30V is better at resisting edge deformation than D2, though my sample size is one knife of each. The D2 edge with 11 degrees per side visibly chipped when cutting a coated Tylenol pill in half, whereas the S30V's chips could only be seen under a 100x microscope. My 52100 had zero issues whatsoever, despite being 3 rockwell points harder than the D2 and S30V.
 
Your results are exactly what I'd expect---D2 forms very large free carbides through HT/temper, basically forming a lot of tiny stress risers throughout the steel, and really doesn't like an included edge angle much lower than 30 degrees. In this regard, S30V beats it as its carbides are smaller and more evenly distributed, therefore making it more able to support a thin edge. On the other hand, D2--to a point--becomes almost sawlike as the steel wears away from those carbides; for a spell its slicing aggression actually seems to increase. Of course, this has limits, and once it's truly dull, it's dull. Having to keep at this thicker edge geometry means, of course, that its initial sharpness can't be as high as a knife with, say, a fifteen degree edge. However, regardless of the material, that thinner edge will be more fragile in terms of blunting, rolling, chipping, etc. so 200 cuts later, the thicker edge may be every bit as sharp as--or possibly even sharper than--the thin. Everything's a compromise. :D

Not knocking S30V--I just like toothy edges on smaller, slicing knives and D2 does that better. Now, if selecting between these two for making a straight razor that was going to be push cutting on top of my skin, I'd take S30V without thinking twice.
 
Hey guys, you really helped me a lot!! Thank you, I'm learning more and more here.
Your explanations are complete and clear for me, I'm understanding better the capabilities of my knives thanks to you and thanks to this forum.

Have a great week!!!!
 
cotdt said:
Great post, t1mpani. In my experience though, S30V is better at resisting edge deformation than D2, though my sample size is one knife of each. The D2 edge with 11 degrees per side visibly chipped when cutting a coated Tylenol pill in half, whereas the S30V's chips could only be seen under a 100x microscope. My 52100 had zero issues whatsoever, despite being 3 rockwell points harder than the D2 and S30V.
Click to expand...
Have you tried a small microbevel? That cured my D2 chipping problems.
 
sodak said:
Have you tried a small microbevel? That cured my D2 chipping problems.
Click to expand...

I eventually did something similar by using a convex edge ending at 24 degrees inclusive for my D2 knife, that solved the problem.

But based on my experience, I like S30V better for its edge stability and ability to hold a semi-sharp edge for a longer time. D2 at 60 rc holds that razor-sharp edge for a little longer than S30V at 59, but it just gets duller and duller.
 
I played around chopping a 2x4 one night with my D2 Rat-7. When I was done I took a newspaper page and the D2 edge glided through it effortlessly. It wasn't 11 degrees per side, but it seemed to work. ;)
 
shunsui said:
...it seemed to work. ;)
Click to expand...

I'd hope so, pine is pretty soft. I'm far more scared of wood that has knots in it or odd shapes that can make your blow glance to one side creating torsional forces, not to mention if it has dirt or grit on it (damned tiny little crystals that are harder than steel! :mad: )
 
Actually, I'm a big fan of hatchets for all that real world stuff.

The D2 RAT-7 is a good knife but I wouldn't go off into the middle of nowhere in winter thinking it's a Battle Mistress.
 
Yes, hard to beat genuine axe geometry (blade not just edge) for toughness. On the other hand, there are things a larger fixed blade will do well that a hatchet won't (planing, soft vegetation clearing) and practice has made me about equal with either clearing branches to about 2" diameter. If I'm doing more, I usually have an axe, but then I'm usually also at home. I haven't had too many occasions to build log cabins while I've been out and about. :D

All that said, I admit that I'm now thinking longingly of my GB wildlife hatchet. I may have to find some work for it before long...

Although, just to be smartass and return to the original point---you'll notice you don't see too many D2 hatchet heads. ;)
 
Funny.... I had a long talk today with Tom over at Chestnut Ridge about this very subject.

http://64.176.233.199/catalog/index.php

or

http://www.chestnutridgeknifeshop.com

He is extremely knowledgeable about this subject and we had quite a talk about D2. More importantly Ontario's D2, of which he told me he has sold many, many versions of their D2 knives.

As mentioned above in an earlier post, he felt like the myth of chipping far exceeded the actuality. He is a seller of products and isn't silly enough to think that all manufacturer's products are always perfect. He never said it didn't happen at all. He did mention though, if there was a defect (of an kind) in one or two knives of a particular model of which 10,000 were produced, it works out to be a pretty small percentage number compared to the overall production run. I pointed out to him that in my line of work (construction) I would be thrilled with that kind of out of the box performance performance from the tools I buy.

Still, before he bought his last batch of D2 knives from the Ontario company, he gave them a call to see if there was any kind of problem with D2. He knows the folks on a first name basis at Ontario and has had this very same "does it chip" conversation with those guys more than once. Still he said, nothing from them. No problems.

Then he told me that he took out one of the RTAK ( 1 I believe) Ontarios and just beat the living hell out of it to prove to himself he was OK selling them. If you are interested in just how far he took it (think metal quarter panel) he will probably tell you if you are really interested.

He is a very well respected member of this community so I wanted to get the skinny from him. He says he might at this time be the largest Ontario dealer, so he has a big stake with them and them with him. So far so good. In fact, he is confident enough in the product that he told me not only would Ontario stand by the product, but that in the event of a non abusive failure, he would also do what needed to make sure the warranty was satisfied.

Good enough for me.

I told him about this video:

http://www.youtube.com/watch?v=jvEkdJJ9wuk

This guy takes his D2 Rat and chops through a seasoned, treated hard yellow pine (not soft or white) 4X4 post. For those wondering, YP can be really hard and is always very resinous. It is used for flooring, decking, structural beams, hard faced plywood etc. Listen to the ring on that 4X4 and you can tell it's seasoned. White pine or green woods *thunk*. Hard woods and especially seasoned hard woods "clink" or ring when you strike them.

Now, he ain't now hammer swinger, and as a nail driver myself he doesn't have any wrist in the swing to make the thing cut. So he literally just winds up beating and chewing his way through the wood instead of cutting through with a nice pattern in his cuts.

No, it didn't shave his arm when he got through. BUT - I counted he hits on that hard pine (hard enough make the knife bounce) and as best as I could tell he hit it about 550 times!

OK... to me, that's a valid chip test. You would want a blade that would stand up to old, hard wood if you were out and that is all there was around for your use. This isn't like chipping into a cinder block "a la Nos". I thought this was a great test, and myself probably would have quit about halfway through thinking that I had satisfied myself the edge wasn't fragile.

Most importantly, at the end of his video, he put his camera in macro mode and did probably a 10X or so view of the entire edge, lit so you could actually see the cutting edge as he moved the camera. The factory edge wasn't chipped, or broken. He found a couple of small flat spots where the edge rolled, but that was it. After 550 hard, chopping whacks! Tom told me he wasn't surprised. If you can get him to admit it, he actually did worse by impacting the blade as well when he was testing his D2.

Tom's only warning was to make sure I was ready to spend the time sharpening the D2 to make myself happy. That won't be a problem for me. Nothing diamonds won't handle.

I bought the RAT 7 D2 from Tom with confidence and at an excellent price. I am looking forward to it being my new camp/utility knife and can't wait to lash it to the pack.

Robert
 
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BLUNTRUTH4U's reviews are very good (except for his negative review of the Tenacious) and his tests are fair. That said, I never got any chipped edges chopping wood either. It's simply not a tough a task as it seems, the wood simply absorbs the shock. If you use the exact same chop against a rock instead of wood, for example, the impulse would be 100x greater.

I've not used the RAT 7 D2, it may very well be extremely tough. My experience with D2 is, if you're just doing everyday tasks, and periodically check the edge on your D2 blade with a microscope, you'll notice small chips. It happens when you hit a staple as you cut cardboard, or cut metal wire, or even a coated Tylenol tablet. Sometimes the chips are visible, especially if the edge is at an acute angle like 11 degrees per side. D2 may be tough, but in my experience the edge stability sucks.
 
What could happen here?

http://www.youtube.com/watch?v=EFpkrk4ikWc

Maybe a deffective unit? Doesn't seem like extreme abusive treatment for a survival knife, specially during the beginning of batoning. The knife was mine and was a present for the guy that was testing it. Of course my friend contacted Ontario and they are sending a new RAT7 in D2!!
I say again, I LOVE RAT7 in D2, but I was surprised with this video. The bend test and that breakage matches with the information that T1mpani gave us.
 
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