Edge Retention Test Results ZDP189 vs S30V -- Surprising Result

[JoHnYKwSt]

Hey guys,
A few weeks ago I finished up a second test run of my S30V Spyderco Paramilitary vs my S30V Michael Raymond Estrella with Michael's personal heat treat. Michael's custom heat treat involves the full gamut -- Cryo in Liquid Nitrogen, Oil Quenching, etc.

Obviously the heat treat is going to be better on the Michael Raymond vs the Spyderco but just how much of a difference? I tested both knives side by side and used both blades to cut the same pieces of cardboard to minimize variables. Both knives are at 30 degrees primary with 40 degree microbevels. Both knives cut along 2.5 inches of edge.

On the first test run cutting cardboard the Raymond blew the Spyderco away, it was not even close. On the second test run the result was the same. I did not need to cut very much cardboard before the Raymond started pulling away in holding its edge.

Because the edge retention on the Raymond was so impressive, I decided to test it vs my Spyderco Calypso Jr in ZDP189, something I had never considered doing since ZDP189's edge retention should obviously be better than S30V. The ZDP189 on the Spyderco I believe is ~65-67RC, much harder than Michael's S30V at only 60.5 RC. This test should also be more fair compared to the one vs the Paramilitary since both the Calypso and Raymond have thinly ground edges. On the first test run the S30V Raymond actually held its edge longer than the ZDP189 although it was very close. I did the test again, and the second time, both steels were even closer. I had to cut a LOT of cardboard for both of these runs but the second run is taking much longer since both knives are still so close in edge retention. When the test is done I will update this thread but needless to say S30V with a custom heat treat is a true performer!

 

[arty]

The Estrella is listed as discontinued on the web, but judging by the replacement, it was likely very expensive. The replacement model folder is over $1000.
How did you sharpen the knives? My Spyderco C22 in ZDP went through a lot of rope when I moved, and showed zero loss of edge sharpness. My Benchmade Minigrip in M4 took months of use, including a period of time when I moved, before I needed to touch it up. The M4 cut an amazing amount of rope before I saw any loss of the edge, while 154cm saw a noticeable blunting in one day of use.
Edge geometry is probably different in the knives you are comparing. You can buy 8 Spyderco Caly 3s for the cost of the custom, and I bet that they will go through more cardboard (all 8) when you need to sharpen the S30V.
I use a $1.50 box cutter for breaking down boxes, so it is rare for me to see any difference in edge retention on cardboard. I wouldn't use any of my better knives for this, since a box cutter does so well, and I can just drop in a new single edged razor blade. Cardboard is very abrasive, and can be used a strop, if one isn't handy.
I don't doubt your results, but wonder how you sharpened them before the test.

 

[JoHnYKwSt]

Hi Arty, both knives were sharpened to 30 degrees and have 40 degree microbevels. I tried to keep all the variables as consistent as possible. Both knives are still cutting through cardboard, I plan to finish the second run hopefully in the next day or so.

 

[Twindog]

Thanks for the test. Do you know how wide the edge shoulders are on these knives? That would be another variable to at least recognize.

My own sense is that S30V responds well to advanced heat treating.

 

[JoHnYKwSt]

Twindog, my guestimation is that the thickness behind the edge is approximately .010". They're both about the same thickness.

 

[me2]

Can you provide some more detail as to your sharpening procedure? I typically use a 17 degree back bevel with a 20 degree microbevel finished on the Spyderco Sharpmaker medium rods, using 20 to 30 passes per side, with very light pressure, along with a deburring step after 10 to 20 passes per side. Following this procedure, edges will typically treetop arm hair, push cut news paper at 90 degrees, no draw, and whittle head hair.

How do you determine when to stop the test? In other words, how do you measure sharpness for comparing the 2 blades?

Was all the cardboard of the same type or was it whatever was on hand?

I've had 2 knives that were very close trade winners over the course of 3 repeated trials. I've also had knives that should be clearly distinguishable just oscillate around each other over the course of a test. After say 40 feet, one was ahead, then after 75, the other was ahead, then change back after 100 ft.

 

[JoHnYKwSt]

Can you provide some more detail as to your sharpening procedure? I typically use a 17 degree back bevel with a 20 degree microbevel finished on the Spyderco Sharpmaker medium rods, using 20 to 30 passes per side, with very light pressure, along with a deburring step after 10 to 20 passes per side. Following this procedure, edges will typically treetop arm hair, push cut news paper at 90 degrees, no draw, and whittle head hair.

Both knives were given microbevels on the sharpmaker browns. After the first run, 25 passes per side with medium progressing to light pressure. Both knives were deburred by lightly cutting into the stone at a high angle then extremely light passes on both sides 2-3 passes unto the knife will readily shave my very fine arm hairs on both sides of the edge. I have never tried to get the edge to whittle head hair simply off the sharpmaker brown stones, I have done that off the white stones. Will definitely try to get the edge to whittle hair off browns in the future.

Was all the cardboard of the same type or was it whatever was on hand?

The cardboard was pretty mixed but pretty clean cardboard. For each piece of cardboard, both knvies made equal cuts on each piece.

How do you determine when to stop the test? In other words, how do you measure sharpness for comparing the 2 blades?

I've had 2 knives that were very close trade winners over the course of 3 repeated trials. I've also had knives that should be clearly distinguishable just oscillate around each other over the course of a test. After say 40 feet, one was ahead, then after 75, the other was ahead, then change back after 100 ft.

I don't have a good way of determining which knife is sharper except by feeling with the skin of my thumb. On the first run of the ZDP189 vs S30V, the S30V was far enough ahead, that I felt like I could end the test although you are correct in that there have been times where I noticed one steel will feel ahead of the other then change back so it is possible that I ended the first run too early. The second run, I plan to just keep cutting until one of the knives will tear the cardboard even with a slicing motion. Suggestions would surely be welcome as to a better way to determine when to stop the test to determine a winner.

 

[bodog]

Hey guys,
A few weeks ago I finished up a second test run of my S30V Spyderco Paramilitary vs my S30V Michael Raymond Estrella with Michael's personal heat treat. Michael's custom heat treat involves the full gamut -- Cryo in Liquid Nitrogen, Oil Quenching, etc.

Obviously the heat treat is going to be better on the Michael Raymond vs the Spyderco but just how much of a difference? I tested both knives side by side and used both blades to cut the same pieces of cardboard to minimize variables. Both knives are at 30 degrees primary with 40 degree microbevels. Both knives cut along 2.5 inches of edge.

On the first test run cutting cardboard the Raymond blew the Spyderco away, it was not even close. On the second test run the result was the same. I did not need to cut very much cardboard before the Raymond started pulling away in holding its edge.

Because the edge retention on the Raymond was so impressive, I decided to test it vs my Spyderco Calypso Jr in ZDP189, something I had never considered doing since ZDP189's edge retention should obviously be better than S30V. The ZDP189 on the Spyderco I believe is ~65-67RC, much harder than Michael's S30V at only 60.5 RC. This test should also be more fair compared to the one vs the Paramilitary since both the Calypso and Raymond have thinly ground edges. On the first test run the S30V Raymond actually held its edge longer than the ZDP189 although it was very close. I did the test again, and the second time, both steels were even closer. I had to cut a LOT of cardboard for both of these runs but the second run is taking much longer since both knives are still so close in edge retention. When the test is done I will update this thread but needless to say S30V with a custom heat treat is a true performer!

So what you're saying is that Spyderco knives with zdp189 costing about 100 to 150 bucks are going to perform as well as a 1,000 dollar custom with s30v?

 

[co556guy]

So what you're saying is that Spyderco knives with zdp189 costing about 100 to 150 bucks are going to perform as well as a 1,000 dollar custom with s30v?

What it really exhibits is the room to grow for ZDP........if a custom HT can do that to S30v, imagine what an optimized HT can do to ZDP

 

[me2]

Both knives were given microbevels on the sharpmaker browns. After the first run, 25 passes per side with medium progressing to light pressure. Both knives were deburred by lightly cutting into the stone at a high angle then extremely light passes on both sides 2-3 passes unto the knife will readily shave my very fine arm hairs on both sides of the edge. I have never tried to get the edge to whittle head hair simply off the sharpmaker brown stones, I have done that off the white stones. Will definitely try to get the edge to whittle hair off browns in the future.



The cardboard was pretty mixed but pretty clean cardboard. For each piece of cardboard, both knvies made equal cuts on each piece.





I don't have a good way of determining which knife is sharper except by feeling with the skin of my thumb. On the first run of the ZDP189 vs S30V, the S30V was far enough ahead, that I felt like I could end the test although you are correct in that there have been times where I noticed one steel will feel ahead of the other then change back so it is possible that I ended the first run too early. The second run, I plan to just keep cutting until one of the knives will tear the cardboard even with a slicing motion. Suggestions would surely be welcome as to a better way to determine when to stop the test to determine a winner.

Try it with the brown medium stones. Mine are very worn, but I can get a hair whittling edge off a 220 grit stone with some practice, so it's definitely possible.

As to how to test sharpness, it all depends on what you want to get into. I use push cutting thread on a scale, slicing plastic grocery bags, slicing paper of various kinds, etc. Try cutting cardboard until the knife won't slice printer paper. Even a Cold Steel Kudu will keep you cutting for much longer than you think. During my cardboard and rope cutting trials, I don't think I've ever had the patience to wear an edge to the point it wouldn't cut printer paper. If you use plastic grocery bags, you'll get to the point you can't cut those pretty quick. Cutting thread on a scale lets you plot the edge degradation through out the test. You can also mark your edge and cut medium or light twine and measure how much of a slice you need to make the cut. Say when new, it might take 1/4" to make a slice in say 1/16" twine with a fixed amount of weight hanging on it. You can adjust up or down to give more or less sensitivity, either increasing twine size or weight or decreasing if it's too much.

I tested a $7 knife and a $75 one against each other and found them to have basically the same edge holding ability. Price isn't necessarily an indicator of edge holding, particularly in folders that require a lot of time and precision to fit together and function smoothly.

 

[Ankerson]

What it really exhibits is the room to grow for ZDP........if a custom HT can do that to S30v, imagine what an optimized HT can do to ZDP

ZDP-189 usually is already at optimal in the 65-67 range.

S30V however tends to be in the 58-61 range typically and with a variety of different HT protocols so performance can and will vary.

 

[co556guy]

ZDP-189 usually is already at optimal in the 65-67 range.

S30V however tends to be in the 58-61 range typically and with a variety of different HT protocols so performance can and will vary.

Thanks for explaining that.

 

[Osmium Gus]

Hello,
I'm new to the forum, but joined to find this sort of comparison to inform my selection of preferred blade steel and grind as an amateur knife maker.
I appreciate that you have tried to control for a range of potential variables.
Are there posts on this forum that contain discussion of standard or agreed methodology for comparative performance testing? Can anyone point me in that direction please?

I would also be really pleased if anyone could point me towards members of the forum who are directly involved in applied research or field trials of the comparative performance of different blade steels and the preferred grind/edge angles for different blade steels?

Thanks,
Gus

 

[JoHnYKwSt]

I finally finished the second run of cardboard cutting and on the second run, the S30V Estrella edged out the ZDP189 Calypso Jr again, but this time by a very slim margin. I had to keep cutting because both steels were so close all the way through the test. Towards the end of the test, the Estrella was able to whittle a wooden chopstick whereas the Calypso Jr would slip, albiet the difference was very minor. Both knives cut through a ton of cardboard and at the end of the test, both were still cutting the cardboard cleanly.

I'm going to be sending the Estrella to Ankerson for further testing, it will be interesting to see how it does on his test and how it compares to other knives he has tested.

Gus, you may want to post a new thread on the testing forum with your question.

 

[JayGoliath]

John,

I'm thinking you might have developed the Popeye's forearm after the tests.

This is a very interesting insight.

 

[Ankerson]

Twindog, my guestimation is that the thickness behind the edge is approximately .010". They're both about the same thickness.

Just measured the S30V blade, it's .006" behind the edge as I got it.

 

[tomsch]

Your sharpening approach sounds just like mine on most of my normal carry knives. I re-profile at 15 per side and use my sharp maker at 20 per side but I use the fine ceramics with a very light pass to de-burr.