Questions regarding testing

[RevDevil]

I am trying to formaulate this question properly, but it is a little tough. My apologies if it does not roll off the keyboard in an easy to digest manner, bear with me.

What could be considered a baseline for testing a new steel? For example, I can see using a Spyderco Endura FFG PE in ZDP, and compare the edge retention/cutting performance compared to a VG10 FFG PE Endura. The size, dimension, geometry or the blade, etc. are all similar (same platform). You can then state with high reliability that one steel performs better than the other.

So when testing different platforms, for example a Benchmade 710 in M390 and a Spyderco Military in CPM-M4, how do you determine what is the better performed when both platforms are so different? Variables would be handle material/shape, overall specs including weight, blade grind, etc. The key is to think in terms of compensationg for the platform differences, if indeed you feel that there are any significant factors that would impact your testing. Thoughts on this? Play nice.

 

[DennisStrickland]

lots of the guys get the edge bevel the same & use a sharpie to desiginate part of blade tested. you are right the best empirical situation is where the models & the grind are identical. when testing different knives against each other there are factors that interfere with getting a 100% correct comparison but all the tests give us some idea of which steel is better. taking several guys results in different mediums over time will give a fairly concise opinion of alloy performance . no tests at this time will give a completely correct analysis.
dennis

 

[Ankerson]

So when testing different platforms, for example a Benchmade 710 in M390 and a Spyderco Military in CPM-M4, how do you determine what is the better performed when both platforms are so different? Variables would be handle material/shape, overall specs including weight, blade grind, etc. The key is to think in terms of compensationg for the platform differences, if indeed you feel that there are any significant factors that would impact your testing. Thoughts on this? Play nice.

Depends on the media cut, cardboard is different than rope etc.

Get the edge bevels as close to the same as you can and use the same test media.

 

[the possum]

What could be considered a baseline for testing a new steel?

I have never seen any sort of testing regimen that would even remotely approach what would be acceptable to most who hang out in this forum, to answer such a question.

If you come up with one, please let me know.

 

[Ankerson]

I have never seen any sort of testing regimen that would even remotely approach what would be acceptable to most who hang out in this forum, to answer such a question.

If you come up with one, please let me know.

You have a point.

 

[RevDevil]

Depends on the media cut, cardboard is different than rope etc.

Get the edge bevels as close to the same as you can and use the same test media.

I watched your videos on the CS Recon 1 and ZDP doing cardboard cutting. I started doing cardboard cutting tests myself about 4 weeks ago. My thoughts drifted towards establishing a baseline of some kind for a specific platform. I wondered if the saber grind Endura sharpened at 30* inclusive would slice the same as a 30* inclusive FFG Endura with the same steel due to the different grind styles.

It would seem a push cut type of test would be more objective than a slicing test. I need to think about this more and see if I can figure something out. I'm glad that you all provided some commentary though.

On another note, I noticed something very interesting in my testing. On my CS AL the steel is appreciably softer than that of my CS Recon 1. I sharpened both to a 21* angle on the Edge Pro and made (50) 12" slice cuts through cardboard with each knife and the AL edge was much more toothy than that Recon 1. I'm trying to see if I can get a small flip camera for the mean time to record and repeat the tests. In the end, the Recon 1 could slice paper much easier than the AL which would just snag and rip it.

 

[knarfeng]

To me, if you don't know the hardness of each blade steel, you cannot compare them. (S30V at 60HRC outperforms S30V at 58HRC. Been there. Done that.)
A blade with better geometry outperforms lesser geometry, when the measurement is based on the pressure required to cut. Buck got 420HC to outperform BG42 on a CATRA machine by using their standard geometry for the BG42 and optimized geometry for 420HC. The CATRA machine measures amount cut by a set pressure.

You have to differentiate between comparing knives and comparing steels. The cutting performance of a blade is determined by
- the geometry
- the hardness
- the composition

If you are mixing all those variables at the same time, you cannot pull out one of them and ascribe the entire difference in performance to it alone. If you want to measure the impact of one variable, you have to hold the others constant, unless you run a statistical experimental design (not an option for users).

The average knife owner is not only limited to the hardness supplied by a knife manufacturer, he likely does not know the actual hardness of his knife blade. So how can he attribute the performance difference to the alloy? By the same token, it is not clear to me that all alloys give optimal performance at the same hardness, nor is it clear to me that maximum hardness is what is desired in an alloy loaded with carbides. Ideally, one would want to determine the optimal hardness (heat treat schedule) of each alloy, then produce blades using that schedule.

A knife maker like Phil Wilson is in the ideal place to do these comparisons. He can fuss with a new alloy and determine the best heat treat for it. Then he can produce knives with blades having identical geometries, heat treated to the optimum for each alloy. Then, whatever cutting measurement he wishes to make is a valid comparison, because he has optimized or controlled all the variables and is only measuring one.

Most of us can only dream of such.

What I have done in my comparisons is:
1) know the hardness of each blade. I cannot control the hardness, but I can at least have a better idea of what I am measuring
2) sharpen each blade to the same edge bevel angle
3) use a method that is not dependent on cutting effort. This negates the effects of blade thickness on performance.

Please pardon the wall of text. This subject is one to which I have given much thought.

.

 

[Ankerson]

On another note, I noticed something very interesting in my testing. On my CS AL the steel is appreciably softer than that of my CS Recon 1. I sharpened both to a 21* angle on the Edge Pro and made (50) 12" slice cuts through cardboard with each knife and the AL edge was much more toothy than that Recon 1. I'm trying to see if I can get a small flip camera for the mean time to record and repeat the tests. In the end, the Recon 1 could slice paper much easier than the AL which would just snag and rip it.

I noticed the same thing.

 

[RevDevil]

To me, if you don't know the hardness of each blade steel, you cannot compare them.

A blade with better geometry outperforms lesser geometry, when the measurement is based on the pressure required to cut.

You have to differentiate between comparing knives and comparing steels.

The cutting performance of a blade is determined by
- the geometry
- the hardness
- the composition

If you are mixing all those variables at the same time, you cannot pull out one of them and ascribe the entire difference in performance to it alone. If you want to measure the impact of one variable, you have to hold the others constant, unless you run a statistical experimental design (not an option for users).


What I have done in my comparisons is:
1) know the hardness of each blade. I cannot control the hardness, but I can at least have a better idea of what I am measuring
2) sharpen each blade to the same edge bevel angle
3) use a method that is not dependent on cutting effort. This negates the effects of blade thickness on performance.

Thanks for your insight Frank. I'm always willing to learn as much as possible from those that have experimented with steels and have the experience that stands behind them. Your post makes perfect sense, thanks for taking the time to provide a really good framework around what I was thinking. With that sort of framework it does really help to organize and develop a starting point for how to determine what is really being tested when a specific cutting action is done (slicing vs push cutting vs (insert test here) ).

I agree that even the most novice tester (me ) needs a solid framework in order to understand aspects of steel such as edge retention, hardness vs toughness and how they impact daily use. This helps a lot.

I noticed the same thing.

I'm glad that I am not the only one. It's not necessarily a bad thing, but I am wondering if the overall edge retention of these knives will have a high variance from batch to batch. Some companies have a very stringent control over their heat treat and cryo treat. Maybe our batch flew under the radar? That is the only thing I can think of that woudl explain (in very simple terms) the difference in edge retention between the Al and R1.


Thanks guys. :thumbup:

 

[RevDevil]

lots of the guys get the edge bevel the same & use a sharpie to desiginate part of blade tested. you are right the best empirical situation is where the models & the grind are identical. when testing different knives against each other there are factors that interfere with getting a 100% correct comparison but all the tests give us some idea of which steel is better. taking several guys results in different mediums over time will give a fairly concise opinion of alloy performance . no tests at this time will give a completely correct analysis.
dennis

Thanks Dennis. I'm going to take this into account as a starting point. Your post makes things a lot clearer, any data will be taken with a grain of salt and a straight forward understanding that numerous variables are unaccounted for (heat treat, ambient temperature, blade style or grind). Thanks.

 

[DennisStrickland]

revdevil sometimes the most satisifying results are from tests you perform yourself. afterall you are the one that will be using the various knives & you can tailor tests to give results important to what use you desire the knife to do. my cardboard tests give me great results on how well blades will perform on deer. sisal rope is'nt what i'll be cutting in hunting season.however sisal is a good medium to establish edge durability between alloys.
dennis

 

[RevDevil]

revdevil sometimes the most satisifying results are from tests you perform yourself. afterall you are the one that will be using the various knives & you can tailor tests to give results important to what use you desire the knife to do. my cardboard tests give me great results on how well blades will perform on deer. sisal rope is'nt what i'll be cutting in hunting season.however sisal is a good medium to establish edge durability between alloys.
dennis

Truer words have never been written. :thumbup:

 

[michaelm466]

I don't think you can concisely compare different steels if the knives aren't the same, for example a military and a 710. However, luckily we have an answer to this, the Spyderco Mules, I don't personally have any, but I think its very helpful for those who do want to compare. However I do think we can compare knife to knife in for instance how a 710 in M390 does against a Military in M4 against how a Griptililian in M4 does, with same edge bevels cutting the same materials. and with enough data you can hopefully see that M4 is consistently above say S30V in different knives.

 

[RevDevil]

I don't think you can concisely compare different steels if the knives aren't the same, for example a military and a 710. However, luckily we have an answer to this, the Spyderco Mules, I don't personally have any, but I think its very helpful for those who do want to compare. However I do think we can compare knife to knife in for instance how a 710 in M390 does against a Military in M4 against how a Griptililian in M4 does, with same edge bevels cutting the same materials. and with enough data you can hopefully see that M4 is consistently above say S30V in different knives.

Michael, that is very true. It would really be nice to have a dedicated folder platform that could serve as a test bed for steels. I know there are sprints and LE, so that will have to do. Sal mentioned an M3920 mule approaching soon. that should be interesting.
Currently, I am trying to develop a simple and easy to replicate testing strategy that will provide at least some valuable data. I started collecting cardboard boxes from work (we have loads). I'm making 20"x12" sections and trying to tst between slicing cuts (sort of a mix between a push cut and a slice) and a straight push cut. Need to compile more stuff before I start any other posts.
Thanks for the reply, every little bit helps.

 

[DennisStrickland]

revdevil i try to get all the boxes i'm going to use in a test from same source [company] also the strength code listed on bottom of box should be identical. one of our formites mentioned that with all factors identical: composition factors can still differ between one batch of boxes to the next batch.
dennis

 

[RevDevil]

revdevil i try to get all the boxes i'm going to use in a test from same source [company] also the strength code listed on bottom of box should be identical. one of our formites mentioned that with all factors identical: composition factors can still differ between one batch of boxes to the next batch.
dennis

Our office uses a lot copy paper, and I always use those boxes that it comes in. Sometimes we have really large boxes for copier toner, computer equipment, etc. I'll usually take those before they get recycled. I am lucky in that there is no shortage of cardboard atwork. last year the company recycled around 160 tonds of cardboard. We have a compactor and make bales quite often.:thumbup: