Where is the CATRA data for serrated edge steels?

[Red Leader]

…and I do mean actual numbers given for specific steels.

If the data is there and I have just missed it, shame on me.

If the data is there and just not released, why?

If the data isn’t there, I think that is an oversight that is doing a massive injustice to the lasting cutting power of serrations.

A couple things I observe: 1) ‘edge retention’ has never been more on the collective consciousness of knife users then right now, and 2) (quite inversely), there is a prejudice against serrations in the general market for a myriad of reasons.

I’ve heard the story that a VG-10 serrated edge was put on CATRA but the test was stopped because it just blew everything else away and kept going and going.


Well?


I think its time we get either some valid tests or some answers. What actually was the CATRA number for that serrated Jumpmaster in H1?


Lets see the SE have its day. It is worth testing. The single best thing that can happen to the serrated edge is to quantify its edge holding in a way that offers a valid comparison to the plain edge, for each given steel.

I want numbers.

[JARHEAD]

Man, look here!
That would be down town.
I tell people that see my Spyderco and lite up, when you learn how to use your blade in the serrated edge you won’t go back!
MAXIMUS CUTIOUS.

[Stuart Ackerman]

Serrations increase the length of the cutting edge.

Morticians find it extremely hard to tell the difference with PE and SE, even in stabbing and slicing motions.

I doubt that CATRA would find a difference, unless the steel in the serrated parts are hardened more than PE edges.

[zhyla]

I doubt that CATRA would find a difference, unless the steel in the serrated parts are hardened more than PE edges.

Are you trying to tell us SE doesn’t have mystical properties?

[Red Leader]

I doubt that CATRA would find a difference, unless the steel in the serrated parts are hardened more than PE edges.

Here is some data.



According to a chart from Larrin’s research, it appears that plain edge steel has serrations beat for 25 cuts, as each cut for the plain edge, up to that 25, cut more cardstock per cut than serrated did. But then things drastically change, as the plain edge takes a nosedive after 25 cuts, and starts cutting drastically less, whereas the serrated edge just keeps going, and going, and going…

Just look at that second chart. Almost unbelievably, a serrated edge shows virtually no deviation in cutting ability at all, way after the plain edge simply plateaues out. The serrated edge runs right off the chart without even slowing down. This is sort of blowing my mind.

And what steel was that test in? Can you imagine that test for K390 or the new serrated Magnamax?

What I’d really like to know is where that ends. Like, how many cuts would we actually see for a serrated edge if it was actually taken to failure?

From my understanding this far, it hasn’t been done. *This* is where I would like to see numbers. In other words, we obssess about these edge retention numbers all day, but can we really have a conversation about wear resistance and edge retention without acknowledging that serrated edges haven’t even been able to be tested to failure yet?


Or have they? And if they have, can we see that data?

[Stuart Ackerman]

I am happy to be proven wrong...

Interesting stuff!

[Evil D]

I'm still so skeptical about serrations and work hardening, there's still more questions than answers. The biggest of which is, if work hardening (such as with H1) is a real thing, how deep does it go into the steel/edge? Can it be sharpened off? Does sharpening add to or remove this effect, or does it only occur from the more aggressive factory grinding of serrations? Why can't we achieve similar results from aggressively grinding H1 into a plain edge chisel grind?

Smarter people than me have said it's a real thing, so I feel foolish to say it's BS, but my personal experiences just haven't added up to there being anything more special about (just for example) SE H1 vs any other SE steel. I really wish there was more evidence to support all this. I did a lot of side by side testing with H1 and LC200N and I saw both steels taking similar edge damage and had similar rates of dullness from the wacky stuff I was cutting. Both performed extremely well, and left me feeling like the results had more to do with the edge geometry advantages of serrations than from the steel itself.

[Red Leader]

I'm still so skeptical about serrations and work hardening, there's still more questions than answers. The biggest of which is, if work hardening (such as with H1) is a real thing, how deep does it go into the steel/edge? Can it be sharpened off? Does sharpening add to or remove this effect, or does it only occur from the more aggressive factory grinding of serrations? Why can't we achieve similar results from aggressively grinding H1 into a plain edge chisel grind?

Smarter people than me have said it's a real thing, so I feel foolish to say it's BS, but my personal experiences just haven't added up to there being anything more special about (just for example) SE H1 vs any other SE steel. I really wish there was more evidence to support all this. I did a lot of side by side testing with H1 and LC200N and I saw both steels taking similar edge damage and had similar rates of dullness from the wacky stuff I was cutting. Both performed extremely well, and left me feeling like the results had more to do with the edge geometry advantages of serrations than from the steel itself.

David-

Fellow David myself!

You make quite a few really good points! The main thing I was trying at is, for the just the small amount of intense performance we have seen out of serrations, there is quite a discrepancy for how little actual research and data there is behind it.


Regarding work hardening, that is only a thing with steels such as H1/2, and not others, yes? Thise steels are a part of the conversation, but it also goes beyond them to include any and all serrated steels. And this is where your comment about geometry comes into its own. There has been such a laser focus from folks on steel composition, and to a certain degree, ‘blade’ geometry, but far less on ‘edge’ geometry, which is where serrations live.


I’ve heard both Eric and Sal mention the highest edge retention Spyderco has ever seen was with a serrated H1 Jumpmaster, and when I asked how that was measured, the answer was ‘CATRA’.

Therefore, I’m extremely interested to know the hard numbers behind that test.

So, from that, two questions: at what point does a regular knife ‘fail’ in a CATRA test, and second, have we ever seen a serrated edge fail in a CATRA test, and if so, where? (Okay sorry 3 questions haha)

[James Y]

Interesting thread.

All I do know (from my own experiences) is that SE blades hold their edges much longer than PE blades *in the same steel.* I could be wrong, but I've long thought it's because the concave angles of the scallops reinforce the edge, and concentrate the cutting force in such a way that the edge is preserved for a longer time than a PE edge.

Jim

[Red Leader]

I wonder if there is some correlation between effective edge length and retention. Meaning: if you stretch out a serrated edge perfectly straight, maybe it is 1.25x as long as its plain edge sibling. I wonder if that would show up as 1.25x the edge retention in the SE format? It is probably a lot more complicated than that. But if it holds for longer that that correlation, I think it would mean that serrated edges are more efficient especially if we are talking about working edges.

From the data thus far presented, it appears as though a plain edge has more potential for higher front end sharpness…but that a serrated edge basically can last at ‘working sharp’ for nearly forever.


I still want to see the hard data for edge testing on SE. If the test has been done, let’s see it. Hypothetical: what is the highest CATRA ever attained, for any steel, any geometry, any edge type, etc.

This would be absolute performance in its purest form, which is then surprising how we don’t know this.

[Evil D]

Well I think literally speaking, more edge length directly equals more edge retention, but when are we ever texting the entire length of an edge?

[James Y]

I doubt the only difference in edge holding between SE and PE is that SE, if straightened out into a PE, would equal more edge length. Because that doesn't take into account the effect of the concentrated force that the peaks and valleys of the serrations have on the material being cut.

Jim

[JARHEAD]

I hope this takes off just like Evil D’s thread did!
Red Leader, good sh!t

[navin johnson]

I don’t think any manufacturers share their testing results

The problem is someone will put a sub optimal edge on a blade, and it will perform poorly compared to another “lesser” steel, and then they will complain about it.

One could also buy their own machinery and do their own testing.

Most of these topics have been covered ad nauseam, and are accessible through the search function

[Red Leader]

Most of these topics have been covered ad nauseam, and are accessible through the search function

I haven't found anything related specifically to CATRA numbers on serrated edges, but maybe my search skills aren't that good.

Any threads you would recommend?

[zhyla]

I haven't found anything related specifically to CATRA numbers on serrated edges, but maybe my search skills aren't that good.

Have you seen how CATRA machines work? I’m not sure CATRA necessarily works on serrated edges.

What is it you’re trying to determine?

[RustyIron]

Have you seen how CATRA machines work? I’m not sure CATRA necessarily works on serrated edges.

The most daunting part of this exercise would be creating identical serrated edges on different samples.

[Red Leader]

I haven't found anything related specifically to CATRA numbers on serrated edges, but maybe my search skills aren't that good.

Have you seen how CATRA machines work? I’m not sure CATRA necessarily works on serrated edges.

What is it you’re trying to determine?

Eh...sort of. But that is what Sal said they used to test the Jumpmaster w/ SE, so I assume that is how it is done and that we can reach some sort of meaningful conclusions with it.

Which leads me to my next question(s): Is the lack of data due to a lack of interest? Or is it because, as was said above, manufacturers typically don't release this info? Which to me, makes no sense at all - after all, if you are trying to sell serrated edges, why would you withhold information which would either 1) help sell your product or 2) help inform the customer so they would make a good decision?

[zhyla]

Eh...sort of. But that is what Sal said they used to test the Jumpmaster w/ SE, so I assume that is how it is done and that we can reach some sort of meaningful conclusions with it.

I (briefly) looked into CATRA and there is a different procedure for serrated edges than the standard CATRA for knives. Again I ask: what are you trying to compare? CATRA is a relative quantification. It lets us draw conclusions such as "this steel at this hardness has better edge retention than this other steel at this other hardness". It's not going to tell you that SE is X% better than PE -- they're different tools and they work different ways.

Which leads me to my next question(s): Is the lack of data due to a lack of interest? Or is it because, as was said above, manufacturers typically don't release this info?

I don't think more than a handful of people even know CATRA is a thing. I can only speculate that Spyderco has a CATRA machine and uses it to characterize their steels. I'd be very surprised if Spyderco or any other company is doing CATRA testing on each knife model. It's a pointless exercise.

I think you're severely overestimating how people choose knives. This is best explained in cartoon form:

Which to me, makes no sense at all - after all, if you are trying to sell serrated edges

From some of Sal's comments elsewhere I think he wishes there was more SE adoption, but if I had to guess Spyderco wants to sell whatever edges people want to buy.

why would you withhold information

This could be a whole side discussion, but it's a business decision whether to publicize test data like that. "Withhold" is a pretty strong word to use here, IMO.

[cabfrank]

I think a company wouldn't want it to be touted as a bottom line reason to buy or not buy a particular model. There are many things to consider when making a knife purchase besides CATRA results, and it could become far too easy to focus on a number that is only one aspect. The same with blade hardness in knives, or overall weight in bicycles, for example.