Steel Edge Retention testing

nozh2002

nozh2002

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After several attempts over last 4 years, I think I finally came to reliable method to test steel edge retention properties.

First I developed sharpness test using cotton thread #10. Result is statisticaly reliable average of weight-forse needed to cut tightened thread.

-------------------------------------------------------------
How to do this:

1. Make table on paper like this:

10
20
30
40
...

2. I mark some point on the edge.

3. I tie cotton thread #10 around small wooden base, fix it with scotch tape:

http://www.youtube.com/watch?v=whobSdS4zyY

4. Put it on simple kitchen spring scale (I have graded by 10g from 0 to 250), make sure it shows zero (it should be some way to fix to zero with stand on) and as gently as possible cut by the marked position on the edge and see what scale shows at the moment of cut - what maximum weight it reach.

http://www.youtube.com/watch?v=MsN3DghiYcw

5. Put '+' in your table to the row for this weight.

6. Repeat 3 to 6 at least 21 times or more

7. on the table filled by '+' count 11th (if you did 21 tests) and mark it as 'X'. This will be median - one of statistical average, most applicable in this case (same used for average price on housing market).

so weight which correspond to median - 'X' will be result of sharpness test.

Of course it will just show some aspect. So this is why I prefer to show entire table like this:

40 +++++
50 +++++X+++++
60 ++++

Which is perfect Gauss curve.

For the last year I am doing out of the box sharpness test. Here results:

Spyderco Military S90V - 20
DiamondBlades Summit Friction Forged D2 - 20
Kershaw JYDII Ti/SG2 - 30
Yuna Knives Hard II drop point - 50
ScrapYardKnives DumpsterMutt SR77 (S7) - 50
Kershaw Tyrade CPM D2- 60
Kershaw Blur SG2 - 60
Marychev Chirok 95x18 (58-59HRC) - 60
Microtech Currahee D2 - 60
Kiku Matsuda Tanto II OU31 - 60
Spyderco Military BG42 - 60
Spyderco Endura ZDP189 - 60
J.P.Holmes CPM 10V - 70
Dozier KS7 D2 - 70
Marychev Nerpa 95x18 (58-59HRC) - 70
Swamp Rat HRLM SR101 (52100) - 80
Busse Meaner Street Red INFI - 80
Kershaw JYD Sandvic 13C26- 90
Kershaw Cyclone ZDP189 - 90
Fallkniven P SGPS- 90
Busse AD INFI - 90 (inspected by #20)
Busse BA INFI - 100 (inspected by #4)
Buck 110 CPM154 - 110
Mission MPK-S -130
Swamp Rat Mini UM SR101 (52100) - 130
Busse BA INFI - 130

Thanks, Vassili.
 
Being able to test sharpness of the edge now I can put some load on it and see how this affects sharpness.

I tried balsa wood, felt and now 1/2" manila rope - fibered structure ot rope make cutting almost independent from blade cross section geometry.

So I cut manila rope:

http://www.youtube.com/watch?v=3LgFny0ZQEU

and then check sharpness to see how this or that steel hold the edge during manila rope cutting.

P.S. Time to time - once a one-two days, I wash edge with soap and warm water in order to clean it from possible dust from the thread sticking to micro teeth (just in case). However results before and after this does not really looks different.
 
I chose to test first INFI (Busse Game Warden) as a favorite to set top of the edge retention scale and 420HC sub zero quenched by Taiwan supplier of ColdSteel (Cold Steel ODA) assuming that it will set bottom of the edge retention.

Results is bit different then I expected

Here my test page with result table at the top followed by full detailed report.

http://playground.sun.com/~vasya/Manila-Rope-Testing.html

Thanks, Vassili.
 
Vassili, I love the data and I really appreciate that you are willing to share it, but it would mean more to me if the notes were in English.

I'm having some probems interpreting the numbers. Am I seeing that the 420HC outcut the INFI?

Could you plot a barchart with the data?
 
I found the way to represent results here. As you may see so far for 220 cuts of manila rope 420HC subzero quenched by Taiwanese supplier of Cold Steel demonstrates better results then INFI. This is big surprise to me be because again I choose this steels based on bias that INFI is the best and 420 HC is just entry level. Testing shows that it was wrong assumption and 420HC not only as good as INFI at least on 1/2" manila rope cutting with 30 degree edge, but even better!

Kind of eye opening experience!

It is not finished yet, and I expect 420HC to show not so good performance on biger numbers on cuts - we'll see. However I expecting same from the beginning...

Here results table (number of cuts, INFI, 420HC, ATS-34, Friction Forged D2, Progressive tempered by Lauri ThyssenKrupp made UHB17VA, CPM S60V (former CPM 440V), CPM S30V, BG-42, INFI):

Cut INFI 420 ATS FF LAU S60 S30 BG INFI
000 040 030 040 020 020 020 020 020 020
001 060 050 060 030 020 040 030 020 030
002 070 050 070 040 030 040 030 030 040
003 070 060 070 040 030 040 030 040 040
004 080 050 070 040 040 040 040 040 050
005 080 060 070 040 040 050 050 040 060
006 080 060 070 040 050 060 050 040 050
007 --- 070 080 040 050 060 060 040 050
008 080 080 080 040 050 060 060 040 060
009 --- 070 080 050 050 060 060 040 050
010 070 070 080 040 050 060 060 040 050
012 080 070 080 050 050 060 060 040 050
015 080 080 090 050 050 060 060 050 060
020 080 070 090 050 050 060 060 050 XXX
025 080 080 090 050 050 060 060 060
030 090 080 090 050 060 060 060 060
035 090 080 090 050 060 060 070 060
040 090 090 090 060 060 060 070 070
045 090 070 090 060 060 060 070 070
050 080 080 090 060 060 060 070 070
060 090 070 090 060 060 070 080 070
070 --- 080 090 060 060 060 080 070
080 100 080 090 070 070 060 080 070
090 110 080 --- 070 070 060 080 070
100 110 080 090 070 070 060 080 080
110 110 080 090 070 070 060 080 080
120 110 090 090 080 070 060 080 080
130 110 090 090 070 070 070 080 080
140 100 080 090 080 070 060 080 080
150 110 090 100 090 070 060 080 080
160 110 100 100 100 080 060 080 080
170 120 110 100 090 080 060 080 080
180 120 110 100 080 080 060 080 080
190 120 110 100 080 080 060 080 080
200 130 100 100 090 080 060 080 090
210 120 110 100 090 080 060 080 090
220 130 110 110 080 080 060 080 090
230 110 --- 110 090 080 060 080 090
240 110 130 110 090 080 070 080 090
250 110 130 110 100 080 060 080 090
260 110 130 110 100 090 070 080 090
270 110 140 110 100 090 070 080 090
280 110 130 110 100 090 070 090 090
300 110 140 110 090 090 070 090 090
320 110 140 120 100 090 070 090 090
340 120 150 120 100 100 070 090 090
360 120 140 120 110 100 070 090 090
380 120 140 120 110 100 070 090 090
400 120 140 130 110 100 070 090 090
420 110 140 130 110 100 070 090 090
440 110 140 130 110 100 070 090 090
460 110 150 130 110 100 070 090 100
480 110 160 130 110 100 070 090 100
500 110 170 130 110 100 080 090 100
520 120 170 130 110 110 070 090 100
540 120 170 130 110 110 080 090 100
560 120 180 140 110 110 080 090 100
580 120 190 140 110 110 080 090 100
600 120 200 140 110 110
650 130 230 140 110 110
700 130 260 140 120 110
750 130 --- 150 120 110
800 130 --- 150 120 110

Detailed test results you may check on that test page I made:
http://playground.sun.com/~vasya/Manila-Rope-Testing.html

Knives used:
Busse Game Warden - INFI 58-60HRC
Cold Steel ODA (Taiwan) - 420HC sub zero quenched 57HRC
Buck Strider Solution - ATS-34 by Paul Bos 59-60HRC
DiamondBlade The Summit - Friction Forged D2 (factory edge) 65-68HRC
Nozh2002 The Shrimp - blade from Laury (Finland) Progressive tempered ThyssenKrupp made UHB17VA 63HRC
Spyderco Military - CPM S60V (former CPM 440V) 59-60HRC
Spyderco Military CF - CPM S30V 59-60HRC
Spyderco Military CF - BG-42
Busse Active Duty - INFI 58-60HRC

Thanks, Vassili.
 
knarfeng said:
Vassili, I love the data and I really appreciate that you are willing to share it, but it would mean more to me if the notes were in English.

I'm having some probems interpreting the numbers. Am I seeing that the 420HC outcut the INFI?

Could you plot a barchart with the data?
Click to expand...

I just did :) I had trouble aligning numbers to make horizontal table in text with this fonts, it take time for me to realize that I may make vertical table instead...

Yes, 420HC outperform INFI up to 220 cuts on 1/2" manila rope with edge 30 degrees - this will be correct statement, based on my results.

Thanks, Vassili.

P.S. As well as INFI seems like doing better after 220 cuts of 1/2" manila rope!
 
I have never used any INFI steel and still I'm very surprised it doesn't stand up to some 420 steel. Could you have a dud?
 
db said:
I have never used any INFI steel and still I'm very surprised it doesn't stand up to some 420 steel. Could you have a dud?
Click to expand...

Wait a bit - I think at 200 I hit the turning point, I just add results for 250 - it is second 130g in a row, so INFI may play better for hardwork in a long run (which it intended to be). So let me finish to do final conclusion.

Again I used INFI for heavy leather cutting and it stands very well - I was surprised myself with this results, so let me finish...

Thanks, Vassili.
 
I'm not sure I'm hearing you right. Cold Steel's ODA I thought was 420, not 420HC. Are you also taking into account blade thickness? To compare steels accurately, blade thickness would have to be the same for all blades tested, wouldn't it?
 
Confederate said:
I'm not sure I'm hearing you right. Cold Steel's ODA I thought was 420, not 420HC. Are you also taking into account blade thickness? To compare steels accurately, blade thickness would have to be the same for all blades tested, wouldn't it?
Click to expand...

That ODA I bought back in 2002 it was made in Taiwan and listed as "420HC sub zero quenched".

Blade thickness does not matter because I am not testing ability to cut but state of the edge after load. It may take more effort to cut media with thicker blade, but this is not what I am focused on. And it is true for solid media like wood, but for rope which has fibers which did not stuck together and just pushed away after being cut by edge sides - their resistance minimal so thickness does not matter too much.

However again this is not what I am looking for - I am looking how one or other steel on around 30 degree edge will be affected by cutting manila rope, because I know how to measure edge sharpness.

Thanks Vassili.
 
I'd love to see AUS8 tested against VG-1. It does look fascinating and I'm glad you know what you're doing. All that number crunching stuff gives me a headache!
 
Nice work Vassili, very interesting. I hope you are able to add a few carbon steels eventually (1095, O1, 5160...) for comparison.
 
Actually INFI outperformed the 420 right from the start.

If you look at the average for the first six cuts, you will notice that INFI was averaging 20 more than 420(80 for INFI and 60 for 420HC), which means that INFI started off more dull than 420. THen if you look at the final number of 140 for 420 HC and 120 for INFI you will notice that INFI deteriorated by 50% while 420HC deteriorated by 133%. That means INFI performed 83% better than 420HC which is a landslide IMO.

but what makes this even more of a smashing vistory is that INFI's performance does not change after cut 100. It stays at a constant level which means that it resists wear at an astronomical level.:thumbup:

It is amazing what can be seen when you correctly interpret results.

Noz, thanks for the test, it only shows how great INFI is....:thumbup:
 
Cobalt said:
Actually INFI outperformed the 420 right from the start.

If you look at the average for the first six cuts, you will notice that INFI was averaging 20 more than 420(80 for INFI and 60 for 420HC), which means that INFI started off more dull than 420. THen if you look at the final number of 140 for 420 HC and 120 for INFI you will notice that INFI deteriorated by 50% while 420HC deteriorated by 133%. That means INFI performed 83% better than 420HC which is a landslide IMO.

but what makes this even more of a smashing vistory is that INFI's performance does not change after cut 100. It stays at a constant level which means that it resists wear at an astronomical level.:thumbup:

It is amazing what can be seen when you correctly interpret results.

Noz, thanks for the test, it only shows how great INFI is....:thumbup:
Click to expand...
You can't interpret results that way. You can say that this test is not completely accurate because they didn't start out at the same level of sharpness, but only through statistical nonsense can you say that INFI performed "83% better than 420HC," unldess you're just making sarcasic comments, in which case I don't think you're adding anything to the discussion.
 
2 Cobalt - Do not turn it into steel fan club battle, please! Let keep it intellegent.
----------------------------------------

I must say that this test kind of change my steel snob attitude. So far this is raw data, but it is absolutely clears lesson that probably there is no best steel, but each steel show good performance in some specific area.

For example 420HC shows
1. Ability to get extreme sharpness better then other steels.
2. Excellent edge holding at high sharpness under small load.

Cons here is that (again may be I am sharpening snob) "average" customer will not sharpen it to level 30 - and if he has initial level 100 (see table of out of the box sharpness where Buck has 110 sharpness level (but for different steel)) then all parts of the table where 420 performs better will be skipped. Like starting from 160th cut 420HC does not shows any better performance.

I may speculate that this is excellent surgical steel, may be razor steel - when you need extreme sharpness for some not too long in time task (surgery, shawing) and you may resharpen it right after.

INFI instead shows excellent performance on lower sharpness and heavy load - which is not a surprise. And if you start from let say "average" customer sharpness (step 160) then it will be for sure better then 420HC.
---------------------------------------------------
I think that collecting this data is pretty useful, also it is interesting to see each test results - showing test range - for example ATS-34 demonstrates solid stable Gauss with small range, while INFI average range twice wider...

I think I must expand cutting at least to 500 cuts and may be over to see performance at very heavy load.

Of course this test does not show impact toughness and stain resistance etc. Just keep it in mind - this is not final word for overall steel performance.

Thanks, Vassili.
 
I happen to think that Cobalt's thread interpreting your numbers is the single-most enlightening post in this thread.

I wonder if the disparaging remarks about Cobalt's positive contribution to this thread would have (could have) been made had the same thing been said by someone other than a well-known Busse fan. Moreover, I don't recall anyone saying that Cobalt is a fan of Busse knives only.

So much for no hidden agenda!
 
on_the_edge said:
I happen to think that Cobalt's thread interpreting your numbers is the single-most enlightening post in this thread.

I wonder if the disparaging remarks about Cobalt's positive contribution to this thread would have (could have) been made had the same thing been said by someone other than a well-known Busse fan. Moreover, I don't recall anyone saying that Cobalt is a fan of Busse knives only.

So much for no hidden agenda!
Click to expand...
It's not about being a Busse fan, it's the fact that the results cannot be interpreted that way. It doesn't make sense.
 
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