Perrin Street Beat - some cardboard cutting, extended comparison

[Cliff Stamp]

I have a Street Beat : http://www.spyderco.com/catalog/details.php?product=263" onclick="window.open(this.href);return false;

Interesting knife, I am still of two minds on the handle. I understand how / why Perrin has designed it, but there are some ergonomic issues in extended use. I can appreciate the stability in hand, even with an open grip which is one of the main aspects of the design, but the handle is a little squarish/boxy. In extended used, while breaking down some boxes for ease of reuse/recycling the handle just feels ill fitting. It just doesn't sit well in the hand comfort wise. But again the stability of working with an open grip is nice.

The edge thickness is a little high for this knife unless it was intended for pretty extreme contacts. The previous user brought the edge angle down to ~10 dps to increase the cutting ability but this leaves a fairly wide bevel which decreases ease of sharpening. It is only a simple modification to flatten the blade bevel however the owner doesn't want that done at this time, hence it is being used as is for now.

An interesting thing came up when I was cutting the cardboard as I noted the performance of the Street Beat was fairly low. I estimate, even without measurement that it was cutting maybe 1/5 to 1/10 the cardboard I would expect on average. However there are two explanations for this :

-this VG-10 is problematic
-this cardboard is extremely harsh on an edge

The cardboard was soft, but fairly abrasive, really scratched up a blade and was very dusty. It seemed likely to me that the cardboard itself could be the issue. I did a little work to see if this was the case or was it the steel itself. I did a standard edge retention measurement. The apex was set with a 600 DMT fine stone at 15 dps. The edge was reset with a Suehiro 'Chemical' 320 stone using plateau sharpening. The TCE was calculated as the measure of edge retention with the stopping point set to be ~1.5% of optimal sharpness. This is beyond shaving. It won't push cut any papers and will start to tear and make ragged cuts on newsprint.

The results :



Legend :

-blue columns represent the edge retention
-the red bars are the error/uncertainty in the results (it is a weighted standard error)
-the white numbers are the TCE results (the column heights)
-the black numbers are the amount of runs done with each

Now from past experience this is a very low score. But I already knew that it would be low because of how fast the cardboard was taking down the edge. It doesn't tell me if it is the cardboard or the knife. The number also doesn't give very much information to anyone else though because unless you have done the exact same work that number won't mean anything obviously. In order to know if it was the knife or the cardboard I added a couple of other knives for a relative comparison. Nothing too surprising, it was a little better than a 12C27 blade (~10 dps edge) and a little behind an ATS-34 blade (~6-8 dps edge). In short the knife is fine, the cardboard is just really harsh to cut.



I had some cardboard left so I added a couple of other knives. A S35VN folder from Mike Gavac and a S30V fixed blade from Phil Wilson (both had ~6-8 dps edges). Again, nothing that surprising, the extra wear resistance from the vanadium carbides was enhancing the performance as would be expected and it also seemed that there was an increased hardness. The hardness was deduced from the fact that after the cutting there was less light reflecting from the edge and under magnification there appeared to be less rolling/impacting :




I still had some cardboard left and this is where it gets interesting. Now I have a pretty decent reference point of a bunch of blades so I can bring in some "unknown" blades/steels and use the existing work as a point of comparison. I used three interesting blades :

-SM100 mule, promoted as an extreme material, I have not had great results with it
-H13, very curious blade material
-M4, Peters, ~63 HRC, but I have had only ok/moderate results with it in the past



Using the existing data I can draw some conclusions :

-the M4 blade appears to have a problem as it should be doing better
-the SM100 blade is consistent with past experiences, it is moderate at best

I spoke to the maker of the M4 blade and it was preground very thin before hardening. This likely could have caused issues with the hardening such as over heating during the soaking or possible micro-cracking in the quenching. I have a few other M4 blades which I can run as points of reference/comparison.

The real interesting thing is the H13 blade. This is ~56 HRC, a fairly low carbide steel but a very high martensite percentage, less than 5% retained austenite as it is hot tempered. The curious thing isn't the average performance but the individual runs. The data tended to be similar to :

-0.5, 2, 0.45, 1.75

When averaged it was ~1 but the scatter was wide. Why did it behave that way? Looking at the apex under 50X magnification then it was seen that what happened on the very high performance runs was that the apex chipped / damaged in a way which produced high slicing aggression (which was the sharpness being measured). If this didn't happen, which is pretty random, then the low hardness and wear resistance produced fairly low performance, ~ 1/2 of VG-10. But when the edge broken down and produced that ragged apex then the sharpness was maintained at a high amount until all those little chips wore down.

I have a few other Spyderco blades to add, at least one, the K2/10V. It depends on how much longer the cardboard holds out.

--

In short :

-issues with edge retention can be the material rather than the blade
-the Street Beat in VG-10 is a solid example of VG-10
-dusty/dirty cardboard can be extremely harsh on an edge
-cardboard ranges massively in influence, a factor of 10 is not unlikely
-having known reference blades really helps pin down reliable conclusions

A few other notes on the blade :

-really nice/practical jimping, not overly abrasive but high traction
-the sheath is so loose it is a functional issue, the knife will actually fall out
-useful size/shape
-interesting approach to security in hand from Perrid with the no-guard guard

[ChrisinHove]

Interesting. What hardness are the s30v and s35v at, do you know/think?

[Cliff Stamp]

What hardness are the s30v and s35v at, do you know/think?

There is a pretty interesting question there - is the HT of those steels optimal or even sensible? If you sampled a bunch of S30V knives would they be similar or higher/lower? At some point I might get some actual metallurgical equipment to measure those quantities. Back to the knives at hand :

-S35VN is 59/60 HRC from Peter's

This is not a measured value. This is just the value that Peter's thinks is generated from a particular cycle that they run which I assume is based on some data sheet (they may do sampling).

In general, data sheets show ideal results and aside from some rare instances, cycles tend to produce softer blades than data sheets if anything so to err on the side of caution I would bet on that blade being closer to 59 vs 60 HRC.

-S30V is 60 HRC, measured from Phil Wilson

Phil does HRC sampling on his blades and so his numbers are real/measured. Phil has commented in the past that in general, again speaking very loosely, that his blades are likely harder than others which have the same hardness value for the same reason I noted in the above. A lot of people just go by data sheets and assume they are getting some hardness/HT result without actually measuring it and in general (again, just loosely) most things that are less than ideal will make a blade softer.

As an aside, I don't want to give the impression that hardness is the only relevant factor, the actual microstructure is what is important, hardness is just the easiest (and cheapest/faster) way to measure something and measuring something is better than measuring nothing.

For example if the quench is less than ideal (and they all are as there is time between the soak and quench and quench and temper in practical utilization) then :

-there will be diffusional transformations (pearlite) which means less martensite, less strength, less wear resistance
-increased retained austenite, very weak/soft and low wear resistance, issues with ease of sharpening

Both of these show up as a lower hardness and thus HRC is a quick/easy way to check to see if they are minimized.

[KevinOubre]

Perrin does a really nice job, at least imo, at making a combative knife. I have always like the Street Beat and Street Bowie. The forward choil gives similar security as a guard would while still maintaing a slimmer profile for iwb carry.It was a really cool and simple solution to getting the security of a guard without having one. Haven't done any utility work with them though. The Street Beat pierces pretty well. Not great in the underhand grip though. Definitely promotes a Filipino style grip.

[The Mastiff]

The Street Beat is a wonderfully made knife but it sure isn't designed to go head to head with a Phil Wilson designed slicing machine. Geometry, hardness and chemistry work against it in cutting comparisons in the above. I wouldn't want to use a Phil Wilson Coyote Meadow as a first choice design if I was contemplating the possibility of having to stab into...a hog for instance. I have seen knives that were snapped or bent on rib cage bones. The Street beat would hold up to that better by design.

I do enjoy reading your knife threads. You do put time into it and I thank you for sharing your results here. We are fortunate having several people here that will take the time to share what they have learned for our benefit.

Once again thanks Cliff.

Joe

[Cliff Stamp]

Definitely promotes a Filipino style grip.

To be frank I have little knowledge/experience there and am unlikely to change in that respect any time soon. To clarify my only issue with the handle, the edges are just a bit squarish. Now it isn't sharp, the edges are rounded but it is just that, rounded edges vs a full round/contour. To me the handle can be felt strongly at the rear of that large index finger choil and all along the bottom. The higher pressure decreases comfort. Similar, the actual end of the blade just had broken edges, it isn't a full round.

Now it might be the case that this pressure is actually wanted/needed for its application to provide greater feedback and/or security in hand. The problem with a lot of martial knowledge is that it quickly descends into mysticism. It is rarely empirically verified and you can often find completely opposing opinions both claiming to be true just by asking different people. Now sure this is true in a lot of fields, but with martial applications often there is no evidence as such, just claims referencing vague experience.

[Cliff Stamp]

The Street Beat is a wonderfully made knife but it sure isn't designed to go head to head with a Phil Wilson designed slicing machine.

When I first started talking about knives there was (and still is) a constant demand for some kind of review/ranking. I was never really interested in that as I was always just curious about some thing not about some kind of ranking. In order to do an evaluation, for it to have any merit you need to have a matrix, what exactly is supposed to be ranked anyway? In this case I hope I was clear I was not criticizing the Street Beat for not dominating a cardboard cutting comparison. I was mainly curious initially why the edge retention was so poor on cardboard as it was cutting only a small fraction of what I would expect. The rest of it just expanded from natural curiosity as I tried to figure out if it was the cardboard or the knife.

I have seen knives that were snapped or bent on rib cage bones. The Street beat would hold up to that better by design

Sooner or later I am going to run into some who has a lot of experience with combat and doesn't mind conducting some experiments as there are a lot of interesting questions there about durability limits, ergonomics, and some very interesting ones about blade style/curvature. If you take a look at some of the knives such as the Civilian vs the Street Beat, in order for both of those knives to even be useful it means that the scope of work/application has to be extremely diverse as the knives are so different.

A big problem with trying to sort some of these out, or even just break ground is that many of the demonstrations are intended for visuals. The zombie-go-boom or Lynn Thompson type cutting which explores little but makes impressive visuals. But its a small world, sooner or later I will run into someone who is curious and has some background/experience and we can generate some data to explore a few topics.

As an aside, I have a pretty big bias in favor of Perrin so I am likely not to be truly objective when it comes to talking about his knives. I know him (indirectly) for a long time through Nemo. They were one of the first guys to be open about the problem with McClung's knives and did one of the first non-promotional "big" reviews of a high ticket knife. That is not uncommon now, but in the late 90's and early 2000's, most reviews were paid/magazines and overly commercial.

Plus he just seems like a pretty cool/chill guy and he often looks like a crazy/hillbilly which makes him almost family :

[The Mastiff]

Cliff, I don't think your report on the Street Beat came across as criticism. In all honesty your results seem like what one would expect. I have a couple Phil Wilson knives as well as the street beat and feel like all are top quality knives designed for different jobs.

Sooner or later I am going to run into some who has a lot of experience with combat and doesn't mind conducting some experiments as there are a lot of interesting questions there about durability limits, ergonomics, and some very interesting ones about blade style/curvature. If you take a look at some of the knives such as the Civilian vs the Street Beat, in order for both of those knives to even be useful it means that the scope of work/application has to be extremely diverse as the knives are so different.

I don't know many people at all that have actual life and death experience with knives and most of the ones that did take a life with a bladed weapon were inmates in a corrections facility. Some got their experience there, some were there for stabbing someone while committing a crime. I can't think of any cases where I saw two guys with knives going after each other. Most were ambushes with more than one knife wielding attacker.

Even guys I know in Rangers or special forces don't know of any/many uses of edged weapons. If it comes to that in their profession they consider that a failure. They much prefer guiding 2000lb bombs onto targets from a long way off, and when using firearms try to keep things quick . Stopping in areas to fix vehicles or check for road side bombs where they are tied down to one spot are their least favorite activities.

If you do get the opportunity to talk to people that have used a bladed weapon for self defense it likely will be in person or by phone but not on a internet forum. If I described a incident with an escaping felon, for instance, where a shooting occurred legally I wouldn't describe much about it because they are reported in the news, and FOIA allows paperwork to be released so it would be very easy to figure out which incident and person was involved. Imagine a correctional officer or cop describing such a scene knowing that persons family or friends could wind up reading it. Same thing with a self defense situation. Public discussions don't happen unless it was like the guy that had to use a Caly 3.5 IIRC when the lion tried to snack on his child.

I will say from a law enforcement perspective a large percentage of stabbings end up with the person doing the stabbing getting some injuries from the knife to the hand they held the knife with. A lot of fingers running up the blade do to no guard to protect the person. It depends on the knife used, the area impacted and some other things. I have encountered situations like the one above where a blade broke, or left the tip in someones body. Hitting a rib or other strong bone can easily stop a small or weak knife like the ones seen in prisons. Most shanks aren't that great yet still capable of doing damage.

One of the times I was stabbed was in the back. Whatever it was got stopped on a rib and felt like a punch. I didn't know I had been stabbed until I fely blood running down my back. That was luck on my part I suppose.

Anyway, That is a ....memorable picture of Mr. Perrin. I got to say it. The guy is a maniac!

Joe

[Cliff Stamp]

Joe, to clarify, I wasn't speaking of people with experience in stabbing other people or more extreme versions of said activity. My brother is a bouncer, he has been stabbed. I also know both wardens and inmates of local prisons, have friends in the military and know trauma surgeons. However while interesting, that kind of anecdotal information isn't that useful outside of entertainment. What I am looking for is ideally someone who is trained in multiple knife heavy martial arts, ideally those of differing focus. I can do test cutting easily, but I don't have the background in those arts so it would be like me evaluating the performance of a lathe. I can operate one sure, but I don't have the skill/experience to know if it was good/bad/ugly.

However someone with extensive experience in multiple combat arts, who was open to looking at questions without bias would be very interesting to explore issues of durability, grip ergonomics/security, tip penetration, general cutting ability, and so on. What exactly it is about how a Bowie is used makes that pattern optimal (if that is the case). How should the edge ideally be configured for cutting flesh and/or heavy clothing? Sure I can do cuts on a simulated target with different blade shapes, but it would be like someone with no experience trying to "test" axes. The conclusions are likely to be misinformed. There is a certain level of skill/knowledge required even to ask sensible questions and I really don't have even the starting background in this case.

[Cliff Stamp]

Here is H1 added in a reground (zero) Pacific Salt :



H1 is an interesting steel which has almost reached the kind of infamy attributed to forging in the late 90's. There is a lot said about it, a lot inferred and while there is truth in the beginning there is also a lot of distortion. To clarify a few issues :

-the high nickle content of H1 means there is a lot of retained austenite
-retained austenite will transform to full hard martensite (~70 HRC) when exposed to high pressures

This is leveraged in a lot of working steels to produce very high wear resistance because not only does the retained austenite absorb the energy of impacts when it transforms, the full hard martensite resists wear very strong as well which means such steels can be very resistant to wear, much more than you would guess from their composition.

However in work like this where the knife is cutting soft cardboard there is not going to be significant work hardening and thus you are left with a moderate hardness, high retained austenite, low carbide steel. In short, it typically will be on the low end of edge retention in any kind of abrasion based cutting. However :

-it is very easy to grind
-extremely tough

and so it works well as a general utility knife. This one is from one of the very first runs of the knife and it has not only been reground several times to flatten the primary, Bruce Rugg also redid the pivot pin to take out all play/slop in the blade. If I really did not know what I was going to be doing with a folding knife then this is one of the ones I would pick due to the combination of cutting ability, ergonomics, durability and very low maintenance.

[ChrisinHove]

I would be intrigued at the difference between the plain edge H1 and a serrated H1 equivalent in this test!

[The Mastiff]

Understood now Cliff. Someone that has spent time with edged weapons like M. Janich, or Doc. Snubnose who does weapons oriented martial arts. Doc S. used to do threads where he would take various knives and work them out on different cuts of meat.

Joe

[Cliff Stamp]

I would be intrigued at the difference between the plain edge H1 and a serrated H1 equivalent in this test!

This is an interesting question and I have looked at a few times in the past but it isn't as simple as it might appear because a serrated blade will continue to cut where a plain edge will not at a given sharpness. How then do you compare the two in a meaningful way? Anyone who has done for example cardboard cutting with a plain edge knife will see at some point the edge will be dull, it will get small flat spots and then it will start to slip/slide and won't make cuts. This then marks the point that the knife is sharpened and sets a limit on edge retention in the functional way that people would determine it.

But what happens when you do this with a serrated blade? The apex does get dull, it does get flat spots, but it won't slip and slide and so you can continue cutting. Now if you compare the two knives at the point where you stop cutting then you are looking at two very different points of sharpness. However if you stop at the same points of sharpness you are looking at two very different points of functional cutting ability.

I think the best way to do it would be to look at both ways and just see the differences. I have a serrated Salt but gave it to my brother as a stable knife and it is one of the few knives I can't get back from him. It simply works far too well. He just leaves it hanging on a nail in the stable all year long, rain, snow and sleet. It does all the cutting in the stable, doesn't get damaged regardless of how harsh the cutting and some of it can be pretty harsh.

[JD Spydo]

Cliff needless to say this is an extremely interesting thread with some great information and facts to back it up too. My best friend who died a few months back was a total fanatic about the Spyderco STREETBEAT model>> it was even strapped on his ankle when he died. He used that Streetbeat for almost everything. He carried a KOPA model folder too for little jobs you use a pocketknife for but he did most of his cutting chores with his STREETBEAT. You made mention that VG-10 was troublesome?? I find that interesting in a way because I use my Temperance 1 model a great deal because I actually find it to hold an edge better than a lot of blades I own and it takes a really nice edge sharpening it as well and for those who are unaware the TEMP 1 has a VG-10 blade. My friend put that STREETBEAT through some pretty rough cutting jobs and he usually only had me re-sharpen it for him about once every two weeks or so>> to me that's not bad overall performance?? So why is VG-10 troublesome?? Or did I take that statement out of context?

Also referring to what you said about H-1 steel has me a bit confused>> and I do realize that it's not known to be a supersteel for plain edges even though I do find it relatively easy to sharpen. But on the other side of the coin with H-1 steel from what I"ve been told>> I believe it was Spyderco themselves that rated it as their best steel for Spyderedges. So why would it be mediocre for PE but yet a super performer for Spyderedges :confused: ?

One last question>> if you could use any other blade steel for the STREETBEAT what would it be?? I'm thinking that knife would be great with XHP from the experience I've had with it?

[Cliff Stamp]

You made mention that VG-10 was troublesome??

I had been using this knife for a little work, cutting down some boxes (flooring) and noted the edge retention was very low. There are two explanations for that :

-the steel itself has an issue
-that particular cardboard was extremely harsh

This is what lead to the experiment I described in the above as I tried to figure out which one was the case. It turned out in this instance that the cardboard I was cutting was very hard on the edge and I was only getting a fraction of the edge retention seen on most cardboard.

So why would it be mediocre for PE but yet a super performer for Spyderedges :confused: ?

First, I would not want to say that the results of one comparison on edge retention could be generalized. Edge retention is a very broad property. A steel could perform poorly slicing rope but do very well carving woods for example. If you talk to people who cut a lot of rope, cardboard and similar then they will rate D2 very highly. But if you look at wood workers then D2 doesn't get a lot of praise in chisels or plane blades. So does D2 have high edge retention or not? It depends on what you are cutting and how.

In regards to H1, when Spyderco did CATRA tests they noted that the serrated version of H1 performed far better than they expected. The serrated blades in general do better in CATRA work but the relative performance of H1 was far more than other steels. Sal had the blade HRC tested and they discovered that the hardness on the serrated blade was much higher. This was eventually attributed to work hardening which took place grinding the serration pattern.

The reason that work hardening happens in H1 is the large amount of nickel. Nickel is an austenite stabilizer. This means that the blade after hardening has a large amount of austenite. When the blade is ground this austenite transforms into full hard martensite (which can be 67+ HRC). Note that this isn't something that just H1 has, lots of steels work harden. This is commonly used in industrial steels which do really heavy work like grinding ore.

One last question>> if you could use any other blade steel for the STREETBEAT what would it be??

I am not much of a ninja so I would be looking at purely a utility application and for a combination of corrosion resistance, ease of sharpening, durability and edge retention, I would pick something like 14C28N or CTS-BD1.

[JD Spydo]

Well I'm looking at this test of the Perrin STREETBEAT from a utility standpoint myself>> because my late friend who just loved that knife did a myriad of different cutting jobs with it including some kitchen/culinary jobs with it as well and he did cut more than his share of cardboard with his I can assure you. What's interesting about cardboard is that it tends to be mean to just about any knife I've ever used to cut cardboard or carpeting either one. Would it be fair to say that a blade steel with more of a toughness property to it be better than VG-10?

Also don't you think that in many cases Spyderedged blades tend to have an advantage cutting materials like cardboard, carpeting and fibrous materials in general? I do like how plain edges tend to cut materials like cardboard but they sure don't last a long time before they get dull. I generally use my Stanley or Hyde box cutter knife for those types of jobs most of the time>> and then I'm constantly sharpening those blades with my DOUBLESTUFF stone :rolleyes: .

Also in your opinion do you think that steels that have a high vanadium content are better suited for cutting materials like cardboard?? The reason I ask that is because when I use one of my SPYDERs to cut cardboard I almost always use my Spyderco 440V, SE Native because it's the one Spyder I have confidence in to do a job involving cardboard and other rough materials. Again Great Thread!

[Cliff Stamp]

Would it be fair to say that a blade steel with more of a toughness property to it be better than VG-10?

For cutting cardboard? Cardboard tends to produce wear by deformation and wear, chipping is usually secondary when hardness and carbide volume are increased to extreme levels to minimize the deformation and wear. If you look at the graphs in the above you can see that a move towards steels such as S30V does give an advantage slicing cardboard, realizing that I am looking at fairly coarse finishes and fairly low sharpness, ~1.5% of optimal at the stopping point. If you look instead at looking at very high sharpness, or push cutting then the optimal steel can change.

Also don't you think that in many cases Spyderedged blades tend to have an advantage cutting materials like cardboard, carpeting and fibrous materials in general?

If you are going to cut until the cardboard basically rips apart then a serrated blade will do that for a very long time. But if you are looking at some kind of minimal effort/force then I don't think that is likely. I have many plain edges blades that will easily for example cut cardboard/ropes with far less force than a standard Spyderco serrated knife. As an exercise, take your favorite Spyderco/serrated knife and cut a piece of 1/2" hemp on a scale so you can see the force you are pressing down. I have knives that can make that cut in ~5 lbs in a very short 2" draw.

I generally use my Stanley or Hyde box cutter knife for those types of jobs most of the time>> and then I'm constantly sharpening those blades with my DOUBLESTUFF stone :rolleyes: .

That stone is likely far too fine and you are leaving fatigued metal on the apex. If you switched to the CBN/Diamond rods the edge retention would likely improve dramatically.

Also in your opinion do you think that steels that have a high vanadium content are better suited for cutting materials like cardboard?

Vanadium is just a particular type of carbide former, there are many (tungsten, niobium etc.). At some level I find the performance starts to level off. I have knives in 121REX, Maxamet, 15V, 10V, etc. . I don't find the performance to keep increasing. At some point the apex stability is too low and the very apex just crumbles. But maybe if you want to keep cutting again until everything starts tearing they would be optimal.

[Cliff Stamp]

Here is the Spyderco K2 and a custom in a very similar steel (k390) added :



The interesting thing is that how you measure edge retention significantly influences how the knives start to be rated past a certain point. The edges dull by a combination of deformation, chipping and wear. The sharpness measured in cutting light cord agrees well with the increase in light reflecting from the apex. However past the S30V/Wilson this correlation is broken. The k390 and 10V knife for example show almost no light reflecting from the apex but they have the same low (~1.5%) sharpness measured by cutting the light cord.

I think what is happening is that the harder steels with the higher carbide volume resist deformation more and as the steel is worn away the very large clumps of the very hard carbides remain and the apex just smooths out at a thickness of < 20 microns. However in the softer and lower carbide steels the apex is thicker (hence it reflects light) but it is more jagged and it keeps being able to slice. I need to do a few things to check this, the most obvious being to cut to an extremely low sharpness (~0.5% of optimal) and look at some knives which are very hard but have a lower carbide volume.

[Cliff Stamp]

Update with a knife in CTS-XHP :



No real surprise, CTS-XHP lands in the middle of the high carbide steels. It is a little better than ATS-34 on slicing edge retention on abrasive media but the difference is small and could easily be overcome by differences in how the knives were hardened.

I have maybe 1-2 more Spyderco's to add, 440C would be interesting and 8Cr13MoV and CTS-BD1. However I want to add a few more runs to the knives already done to see if I can reduce the spreads a little.

[tvenuto]

Would be very interested to see how BD1 fits in. I feel like it has a completely unfounded bad rep. I know you would retort that most people's steel opinions are unfounded, but that's another issue.