1. Welcome to the New & Improved BladeForums. New software info here. Please report problems in Tech Support, and read existing threads before posting! - Spark
  2. I've changed the default forum style to Flat Awesome based on feedback. Don't like it? Click here to change how the forums look Feedback on this is welcome here.

thiner edge stability

Discussion in 'Maintenance, Tinkering & Embellishment' started by goodshepherdknives, May 22, 2013.

  1. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    hello all. im a fan of either thick beastly knives like 5/16ths inch thick, or either extremely thin edge grinds that require more maintainence. all knives experience performance trade offs in terms of strength and edge holding when thin, but has anyone noticed their zero or scandi grind or thin profile that seems to hold up better than other steels for a shaving edge under edc use? thanks
     
  2. IF cutting materials without placing them against a hard backing, I've liked how thinner edge profiles hold up (I'm talking maybe 30° or less, inclusive). An edge with thinner geometry is a much more efficient slicer, requiring much less force exerted directly against the cutting edge. That really helps with edge durability, so long as the thinner edge doesn't get slammed into a hard substrate under the material being cut. A thickish edge (>40° inclusive) is more 'durable' in the sense that it's shape won't be altered as severely when contacting something hard. But I don't see much advantage in maintaining the geometric integrity of a thick edge that doesn't cut as well anyway, even when it's 'sharp'. A thinner edge can continue to function well for most real-world cutting tasks, even after the shaving sharpness goes away, because the underlying geometry behind the edge still works. BUT, a thick edge will be immediately blunt and unusable as a true cutter/slicer, for the most part, just as soon as the crisp apex is gone. After that, it's basically just an axe-edge for hacking at stuff. Most of my real-world EDC uses for a 'knife' don't call for that.


    David
     
  3. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    i have observed this as well. imattempting to discover steel and heat treat differences and seeing which are better to use
     
  4. Best way to figure that out, is to just try them out. Obviously takes time, but I guarantee you'll appreciate what you learn from it. :)

    I have a carbon-bladed Opinel that I've taken about as thin as is reasonable. No idea what the actual edge angle is, but I've zero-ground it down to very, very thin. It is very delicate and vulnerable to edge impacts. But, for fine slicing, it's a dream. Goes through thick leather like a laserbeam. That alone is worth it, and I have no regrets in taking it that far.


    David
     
  5. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    um this is what im more looking for. ive done a test on peperboard over this year as cereal boxes ect gathered up, and i measured how many feet long each one cut before it wouldnt shave. it would get stropped back to shaving though so it wasnt dull, it was just edge stability. they all started 16k finish edge would whittle hair. some were fromfactory dimensions, some were my own reprofiling.
    i just pulled them off the shelf and went after making sure they were sharp. not any of these knives are similar. it was just something i did for fun and still plan on adding to someday. next test will be a taped off limited quantity of edge cutting manila rope. no they werent all the same edge geometry/blade shape/thickness/hardness, i just did it

    Spyderco 440c 90 feet *toothy 600 grit* the knife tested here was the cat with a 2 1/4 in. edge length
    Spyderco 8cr13mov 96 feet 40 ( the tanacious 3 inch cutting edge, sharpened pretty thin
    Spyderco 3cr13mov 65 feet ( the grasshopper
    Benchmade aus8 72 feet 35 strops (ambush at 4 inch cutting edge length
    Spyderco vg 10 357feet 75 strops ( stretch 3 1/4 cutting edge length
    Spyderco zdp 189 195 feet paperboard, 45 corrugated (manbug 1 3/4 edge length
    Benchmade 154cm 144 *thing profile hollow ground* (griptillian 3 1/2
    Buck 420hc 40 feet *thin profile hollow ground short blade* ( buck maverick 2 1/4 cutting edge
    Boker 440 c 60 feet ( gents scalpel 3 inch cutting edge length
    Benchmade N690 180 feet 15 strops to shave again (monochrome 3 inch cutting edge
    Benchmade d2 155 required cardboard to strop several times (bone collecter grippy, i dont have it
    Benchmade S30V 145 feet *thin profile ( dejavoo 4 inch cutting edge length

    knives i still have to test are sr 101, carbon V, esee 1095, gerber 12c27n, vg 1, and some others.
     
    Last edited: May 23, 2013
  6. The Spyderco VG-10 really jumps out, in that list (357 feet of cardboard). If it were me, I'd be looking real close at what's special about that edge, and try to closely emulate it's physical characteristics in some of the others (edge angle, grind V/Convex, blade thickness, etc.).

    The downside in attempting to compare all these is, there's so many other variables at play, besides the steel and sharpening & finishing method. Even at the same edge angle, the overall blade thickness really makes a difference, due to the 'wedging' of the blade into the material. Even the 'test' material itself (the cardboard) is hugely variable in how it cuts. Lots of 'impurities' are built into it (even dirt), especially if it's made from recycled materials.

    The upside to all that is, it's great fun to keep experimenting with it. No shortage of variables to individually tweak, and therefore an endless number of 'projects' to learn from.


    David
     
    Last edited: May 22, 2013
  7. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    definately true, and these were things i thought of also but i didnt really have much else to do. my next idea was to try the top five or three or howver many and use something like paracord and tape off all but say an inch so that way the same square foottage is being used so to speak and see if i can get some more accurate results. perhaps then it will give me a good idea of where to start with for my own projects, and see where to start. then i could test three of the same thickness and grind, have someone pro heat treat them since i dont have the means, test again on sever al materials, and pick my favorite
     
  8. Big Mike

    Big Mike

    Aug 30, 2006
    :confused:
    :confused:



    Here's my take on this issue.


    I love thin edges and thin blades where appropriate.

    Some steels lend themselves to this more then others.


    Take a super tough steel like Crucible's CPM-3V.

    It can take a thin edge behind the edge, or a thin overall cross-section, even at a hardness that offers great edge retention.

    Other steels would require a thicker cross-section to achieve similar levels of toughness.


    What I don't like, and something I often see from some of my favorite knifemaker's, is the trend to make knives in tougher steels using the same cross-section as their lesser counterparts, thus loosing the advantage gained by the superior steel.





    Big Mike
     
  9. pwet

    pwet

    Feb 13, 2009
    in my opinion you are looking for "simple" tool steels with a proper ht aiming the top of their hardness ange. you are in the custom territory.

    i have a couple of performance oriented custom fixed blades. some are 145sc steel, 1,45%C and about nothing else. outstanding steel. one is c130, the same a bit less clean and 1,3C, some are 115w8/1.2442 tungsten steel, some 110WCrV5/1.2519/silversteel.... all work wonder for keeping the fresh of the hone edge longer àt the shallowest angles .... something no production stainless can offer.


    japanese kitchen knives also comes to mind, aogami super and shirogami 1 (basically japanese c130)... but not so much folders or utility fixed blades in those steels.

    another great exemple of heat treat doing most of the job. my caly 3.5 is a great knife, with aogami super, great steel. HT'd by spyderco with customers in mind it doesnt hold a candle to simpler steels pushed higher in hardness.

    for extreme low angles forget high carbide stainless.
     
  10. Magnaminous_G

    Magnaminous_G

    Jul 13, 2011
    Question: why?
     
  11. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    From the test numbers I can say your testing is flawed.
     
  12. singularity35

    singularity35

    Mar 1, 2010
    Can you please elaborate?
     
  13. me2

    me2

    Oct 11, 2003
    Try to get some very hard AEB-L/13C26, 1095, M2, M4, O1, and/or 52100. This will all be custom type knives. Hardness should be at least 62 HRc.
     
  14. marthinus

    marthinus KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Dec 10, 2006
    You might find the following interesting related to steels and very low angles. It is done by metallurgist Roman Landes.

    Knife Edge Diagram

    Here is what he had to say:


    Original thread:

    http://www.bladeforums.com/forums/showthread.php/344902-Edges-and-Steels?p=3043379#post3043379

    Here are also some definitions and you can see the difference between a knife steel such as 12C27 and 440C in microstructure at the edge.

    http://www.smt.sandvik.com/en/products/strip-steel/strip-products/knife-steel/knife-steel-knowledge/
     
    Last edited: May 23, 2013
  15. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    My first clue was that VG-10 was beating everything, my second was that none of the knives had enough similarities to conclude a proper result.
     
  16. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    yes he was butt hurt his favorite wasnt on top
     
  17. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    my testing was what it was. a two inch zdp 189 blade was better than a 2 inch 420hc blade. the spyderco 440c blade had a different kind of edge finish, some were thin, some were not. i have not tried all of the steels with all of the possible configurations to do a knife, im not God. i was just pulling them off the shelf and trying them over time and recorded them, i didnt ask questions. i dont have all of the different steels available in my personal collection inall of the same blade length in all of the same grind type, just chill it was just for the fun of it.
     
  18. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    your scion toaster is ugly, why drive it? different people like different things. i enjoy my cold steel recon scout at 5/16ths inch thick. i dont use it to remove splinters i use it to cut trees down. my spyderco bug does not do well at falling trees but it does very well at opening boxes and cleaning dirt from under my nails. although i generally could use the scout for that if i had it, because there is no kill like overkill, so i would open a granola bar wrapper with a katana just because i can.
     
  19. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    I have a favorite?

    There are things called test procedures, there is a reason they are followed. If ignored then you just have a bunch of random numbers.
     
  20. goodshepherdknives

    goodshepherdknives

    297
    Apr 7, 2013
    yes they are a bunch of random numbers. i never claimed that i was trying to prove in the above test which was better by brand or steel, i was simply stating what which was as a went over a few months to keep a record myself. i used it as an example to my original question which has been completely ignored. i did not jump up and down explaiming "whoo hoo this ones this best and is better than all the rest" claiming it was number one, i did not submit this test to a certain brand and tell them they arent good knife makers. it was an inicial what i had on hand at that time test i did from my collection
     

Share This Page