Accidental Discovery - S90V

[Stand Straight]

My old polycarbonate chair mat has reached the end of the line. Broken down; chair wheels sink into the ruts that have developed with years of use. Gotta go! So out of frustration I decided to cut the mat where the wheel indentations have broken through from one end to the other end allowing me to turn the mat 180 degs thus giving the chair wheels new territory to roll around on.

Being too lazy to venture into the garage to get a jig or sabre saw to do the muscle work of cutting the 3/16” poly, I grabbed my nearest knife, a Spyderco ParaMilitary2 s30v stropped sharp (30° inc). Putting a rag behind the spine for hand protection and pulling and rocking the blade, I could make no progress. My next nearest knife was my new Spyderco Manix2 XL s90v (factory edge), so what the heck. Let see what happens. So same setup with rag; pulling, rocking and to my amazement I was making progress. Slow…but cutting. I exerted a lot of effort but I cut approximately 2 feet.

Next I needed to check the damage. So my previously phone book paper cutting sharp PM2 would not even start cutting the paper. Rolled edge. Next tested the Manix and the s90v sliced the phone book paper like it had never even been used to cut the poly mat.

Now, I know there are other things to factor in here such as blade geometry and other things that I don’t understand, but from a purely user tasking perspective, doesn’t this says a lot for the S90V steel in retaining that edge? Where am I going wrong on my extremely superficial analysis? Have you had any pleasant or disappointed surprises with this steel?

 

[o4tg]

S30V is indestructible for light to medium tasks, but in my experience with hard use it's pretty low on the scale for wood, plastics, and soft metals. I'm sure I'll likely get belittled for that, but I think it's a terrible hard use steel.

But then again I've read that S90V was developed with hard(er) use in mind.

 

[zl1]

picsss!

the s90v Manix 2 XL's look pretty great

 

[Bugout Bill]

Now, I know there are other things to factor in here such as blade geometry and other things that I don’t understand, but from a purely user tasking perspective, doesn’t this says a lot for the S90V steel in retaining that edge? Where am I going wrong on my extremely superficial analysis? Have you had any pleasant or disappointed surprises with this steel?

That's where you are going wrong.

 

[gooeytek]

edge geometry is key.

 

[o4tg]

edge geometry is key.

Key to about half of the equation.

It drives me nuts that some people think it's all in the steel, and on the flip side of the coin some people think it's all edge geometry. The truth is they're both equally critical, and should be picked for the intended use.

 

[Bugout Bill]

Key to about half of the equation.

It drives me nuts that some people think it's all in the steel, and on the flip side of the coin some people think it's all edge geometry. The truth is they're both equally critical, and should be picked for the intended use.

And the fact that you have just subjected a knife to a variety of random forces while cutting into the hard material. And the PM2 edge could have been burred or overstressed from stropping.

Weird things happens, I've had the factory edge on a AUS8 Cold Steel SRK chip out after chopping into green wood. I sharpened them out and chopped the same wood and the edge was unaffected.

 

[idaho]

No, it does not

You were "cutting" extremely resilient material, with so much force, that 30 deg edge got deformed plasticly, most likely to the left, if you were using right hand.
I wouldn't expect much difference on s90v with 30 edge.

 

[Stand Straight]

And the fact that you have just subjected a knife to a variety of random forces while cutting into the hard material. And the PM2 edge could have been burred or overstressed from stropping.

It seems logical to me that outside of a laboratory environment, the knife in use will always be subjected to “random forces.” That’s what knives are about. If you’re whittling some kindling wood for a fire, skinning a deer, breaking down a cardboard box, knife angle flexing in and out of optimum position to the object being cut…it’s all about randomness.
Blade shapes; similar. Blade steels; different. Material being cut; identical. Stresses; random.
Seems like outside of the lab environment, the S90V is superior in edge retention.

What do the metallurgists say? I respect your insight and knowledge. You can meld the lab with the practical.

No, it does not

You were "cutting" extremely resilient material, with so much force, that 30 deg edge got deformed plasticly, most likely to the left, if you were using right hand.
I wouldn't expect much difference on s90v with 30 edge.

Interesting perspective.
There was a vast amount of difference.

 

[RevDevil]

S30V is indestructible for light to medium tasks, but in my experience with hard use it's pretty low on the scale for wood, plastics, and soft metals. I'm sure I'll likely get belittled for that, but I think it's a terrible hard use steel.

But then again I've read that S90V was developed with hard(er) use in mind.

Sorry to disappoint you, no belittling here. You probably already know this, but for those that do not I will say that S30V was specifically designed to be used as cutlery steel as it's intended primary use. Some of the fixed blades made in S30V would really surprise you at just how much hard use they can take while not breaking or losing a solid working edge. S90V is quite amazing though, especially thin blade stock, it slices effortlessly for a long time.

 

[idaho]

Interesting perspective.
There was a vast amount of difference.

Was s90v 30 degree as well? Or was it 40?

 

[Bugout Bill]

It seems logical to me that outside of a laboratory environment, the knife in use will always be subjected to “random forces.” That’s what knives are about. If you’re whittling some kindling wood for a fire, skinning a deer, breaking down a cardboard box, knife angle flexing in and out of optimum position to the object being cut…it’s all about randomness.
Blade shapes; similar. Blade steels; different. Material being cut; identical. Stresses; random.
Seems like outside of the lab environment, the S90V is superior in edge retention.

You need some sort of controls before you can draw any conclusions:

-The blades could be sharpened to identical profiles.

-Cut a abrasive material in a controlled manner. There is a reason why cardboard and rope are so commonly used for edge retention.

Instead, you subjected two different knives with edges of different condition, did work with them, and concluded that the factory edge on the Manix was better. That is not a well founded conclusion. It's as bad as any of the "testing" that John Davis did.

 

[Bugout Bill]

Was s90v 30 degree as well? Or was it 40?

The Paramilitary was also stropped. There is a possibility that it could have been overstropped and the edge overstressed, leading to premature failure when the cutting was done.

 

[gooeytek]

Key to about half of the equation.

It drives me nuts that some people think it's all in the steel, and on the flip side of the coin some people think it's all edge geometry. The truth is they're both equally critical, and should be picked for the intended use.

Exactly. S30V and S90V from Spyderco should be tough enough and stay sharp long enough to handle the plastic material. In this case, the difference in the edge geometry between the two blades was the key. The bladesteels were already up to the task.

 

[Twindog]

As a rule, S30V is tougher than S90V, but S90V will hold an edge longer. There are too many unknown variables in your experiment. Interesting, but not conclusive.

I am surprised that S30V rolled on you. I've chipped S30V, but never rolled it.

 

[KennyB]

I thought Spyderco sharpened to 30 degrees. So shouldn't both blades be of the same geometry?

Oh and I was never impressed with S30V from Benchmade. Wasn't really unimpressed, but it didn't seem to be "invincible" or anything. It rolled on things you'd think it would roll on. Never had it chip though which I think is the point with S30V, to be a little on the tough side right?

 

[Bugout Bill]

I thought Spyderco sharpened to 30 degrees. So shouldn't both blades be of the same geometry?

Oh and I was never impressed with S30V from Benchmade. Wasn't really unimpressed, but it didn't seem to be "invincible" or anything. It rolled on things you'd think it would roll on. Never had it chip though which I think is the point with S30V, to be a little on the tough side right?

Tougher than ATS-34 I think. Which isn't saying a whole lot.

 

[Stand Straight]

You need some sort of controls before you can draw any conclusions:

Instead, you subjected two different knives with edges of different condition, did work with them, and concluded that the factory edge on the Manix was better. That is not a well founded conclusion.

I totally agree with you BB on controls, but this was a tasking situation with no controls needed. What I concluded was that in MY non controlled, non scientific usage of two knives with different steels to do one task, in that specific task the S90V performed it better; S30V did not. No controls needed. I simply wanted to complete a task whether with a hatchet, a skil saw, sabre saw, or my teeth, but chose a knife. And I agree with you that it is not a well founded conclusion...if I was trying to portray my experience as something other than a user based event. Certainly not scientific in any stretch.

Was s90v 30 degree as well? Or was it 40?

I don't know. The s90v was factory out of the box. As I recall reading, there doesn't seem to be a "one bevel fits all." Is it factory specific? Don't know, but usually less than 40 from what I've heard.