8670 v. A2

Discussion in 'Fiddleback Forge Knives' started by Fishcharmer, Jan 22, 2021.

  1. Fishcharmer

    Fishcharmer Gold Member Gold Member

    Feb 1, 2020
    A couple of months ago, I had a conversation with @Cohutta about the relatively new 8670 steel. As my knife use runs more to the hunting, general purpose, and EDC realm, rather than hard use bushcraft, he was curious what my impressions were of it (from the user end), and specifically how it compared to A2. As a result of that conversation, I decided run a little test.

    Let me mention a few things first:

    1. I am a knife enthusiast, not a knife maker. I know next to nothing about metallurgy, heat treatments, blade design, ect.. I know which end of the knife to hold(usually), and how to operate it safely(usually)...that’s about the extent of it.
    2. This test was not comprehensive, nor especially scientific. The controls were too rudimentary, the variables too numerous, and the data points too few to arrive at any definitive conclusions. It was a very narrow test undertaken to satisfy my own curiosity.

    The Knives

    For this test I chose four knives:

    1. FF Pack Rat 1/8 8670
    2. FF Toboggan 1/8 A2
    3. Cohutta Mini Strebig 3/32 A2
    4. FF Toboggan 3/32 8670
    I wanted the edge on each knife to be identical, so I sharpened each at 20 degree down to .5 micron on a Wicked Edge. This is a much finer edge than I would normally take a hunting knife, as you lose some “bite” when field dressing, and can also have some issues with over-cutting, and edge retention. However, since part of the comparison was to be a test of edge stability, and retention, I wanted to stress the knives there a little more..

    The Test

    The test consisted of processing game(primarily deer) from field-dressing to vacuum-bagging. Normally, I would use different knives in each step of this process, but we used these four exclusively. Over the course of 4 weeks we worked up 22 deer(ours, friends, family,) 1 bear(neighbors), 13 geese, and 5 ducks. In addition, we used them for just about every other little cutting task we encountered while hunting(ex: cutting zip ties on temp waterfowl blind, and whittling a field ramrod to clear snow from a rifle barrel). 20210122_165346_resized.jpg
    I am very diligent about stropping my knives. For the purpose of this comparison though, we neglected stropping completely for the first stage of this test. We basically cut until we couldn’t anymore, resharpened the edges to a pristine condition, and then stropped as necessary from that point on.

    We made it a point to be hard on the edges. We went over and above what would be considered normal(or wise) use. We intentionally raked bones, cut through ribs, scraped ball joints, and batoned through pelvic bones. I’d be lying if I said their weren’t a few teeth-gritting winces along the way. We also neglected oiling the knives after cleaning(during the first week of the test) to see how each steel reacted. 20210122_165409_resized.jpg


    We were able to see a few differences between these two steels based on the paces we put them through.

    1. Edge Retention: This one was not especially close, and the biggest difference I saw between these two steels. Although 8670 holds a very good edge (The 1/8th 8670 processed 2 deer start to finish, without stropping, before it needed resharpening...The last bit was a little rugged), it was ready for resharpening in about half the amount of cutting the A2 got through. The 3/32 A2 could still shave hair after processing a deer start to finish! During the second part, when we were stropping diligently, the 8670 needed stopping sooner, and more frequently than the A2. It also seemed like we could just get A2 “sharper”.....Winner: A2
    2. Toughness: I’m concerned we pulled a few punches on this part of the test, but even given that there was enough of a difference between these two to declare 8670 the clear winner. We did things with the 3/32 8670 that you shouldn't do with a hunting knife, and didn’t so much as roll an edge. It really was impressive. All of you who have used A2 know how tough it is, but we still managed a couple dings, and rolled a couple of edges(no chips).......Winner: 8670
    3. Sharpen-ability : There are trade-offs in everything. If you’ve got a knife that holds a fantastic edge, chances are it’s going to be a bit harder to sharpen. That was the case here. The 8670 is insanely easy to resharpen. If you don’t let the edge get to far gone, a few passes on the strop, and it’s working sharp. I have never considered A2 a difficult steel to sharpen, especially when compared to some of the “super steels”, but it doesn’t match 8670 in this department. I did find that once we got to the second part of the test, and were diligently stropping, there was not as much difference between the two steels(but there was some). If you let both get to a sad state of dullness, it took much longer to get A2 back to sharp-sharp......Winner: 8670
    4. Corrosion Resistance: We didn’t let this part of the comparison get out of hand, but we didn’t need to. It was pretty clear that A2 holds a decisive advantage. If you dig a knife that patinas with ease; 8670 is the way to go. If you want your knives to look newer longer; go with A2........Winner: A2 20210122_165307_resized.jpg


    One thing I can say for sure is that both A2, and 8670 are top notch, hard use knife steels. They both do what you ask them to do(and then some). But, were we able to answer which steel is better?

    It depends...

    What tasks will you be using the knife for? How harshly will you treat it? How often will you use it? how frequently will you oil, or strop it?

    If I has looking for a heavy duty Bushcraft Knife, Camp Knife, or Chopper...8670 without thinking twice. It’s approaching indestructible, and you can sharpen it on a rock.

    If you are looking for an EDC that doesn't see hard use, but you want it to be hair popping sharp when you need it...maybe look at A2.

    I think both are outstanding as hunting knife steel, but which you choose will depend on how diligent you are with keeping up the edge, and after use care...For a hunting knife, I Personally like what A2 offers, but will continue to use my 8670 knives when I head to the woods..

    I'm really interested in hearing your thoughts on the differences you all have seen between these two steels. Regards, Fish
    Last edited: Jan 22, 2021
  2. rileybassman1

    rileybassman1 Gold Member Gold Member

    Aug 12, 2012
    Great write up! This is something I have been wondering myself with some newer fiddlebacks and exactly the scenario/usage that I am most interested in :) Very much appreciate you taking the time to write this!

    No experience with 8670, but I have a fair amount of hunting experience in the last several years with A2 and 3V... both are excellent field use steels. I grew up on Buck's famous 420HC as well as other's AUS6/8. Both suffice but left me wanting... so I went into carbon land for the last 10 years or so with A2 and 3V being my favs.

    With some of the newer super steels, I ventured "back" into the stainless realm this past year with a few nice fixed blades in Elmax, M390, 3g, and S45vn. At this point in time... I *think* my overall favorite "hunting" steel is 3V... but that's subject to change lol. Stainless super steels tend to hold an edge longer, and keep until clean up longer, but feel a tad more fragile in the edge... a good tool steel, while it lacks the crazy edge retention, is usually quite sufficient for any field dressing, or sometimes in my case, back country quartering (elk usually) which can be sorta edge demanding getting around/through the hind quarters etc and basically completing an entire bone out in the field. Tool steels seem to survive the "sternum split" and leg tendon cutting better then stainless steels IME... but I didn't have a good chance to really test some of my newer stainless steels this year... so I am curious there.

    I don't find many steels "hard" to sharpen, but do find some "easier" to sharpen then others so it is interesting reading about 8670... how do you feel it compares to like O1 or a 80crv2 type of steel?

    Love the conversation and look forward to what others experience and contribute!
    Last edited: Jan 22, 2021
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  3. Tristndad

    Tristndad Gold Member Gold Member

    Nov 16, 2020
    Thanks for taking the time to do this write up! I really enjoyed your take on the two steels. Informative, properly opinionated, and open to other peoples experience. Nice job.

    I have been primarily using A2 for the last dozen or so years and feel it's been a great "one for all" steel. It doesn't outshine in any one category, but it is simply reliable for all categories.

    I am still getting a feel for 8670. So far I have found I can get it extremely sharp, but after mild use it looses that touch. However, I can beat the living steel out of it and it will remain "field sharp". That is just fine with me as I never set out with intentions of shaving with my knife.

    I've never really cared much about a patina. A shiny knife looks as pretty to me as a rainbowed or Grey one. So not much to say about the two steels in those regards.

    If I had to choose between the two steels I would go with the one with the prettier handle.
  4. Bmurray

    Bmurray Gold Member Gold Member

    Feb 9, 2012
    great review. I too have found the 8670 to loose it's edge relatively fast compared to A2. I know Russell has been working on optimizing hi new A2 HT and has come up with a very good sweet spot. IMO 8670 sort of responds like O1. I can get a super keen edge on it fairly easy, very tough but doesn't last like A2. However I'm a huge fan of s35vn like used in the Pro series. I can get a fine edge, last a long time, it's tough as nails, and is a true stainless.
  5. Comprehensivist

    Comprehensivist Platinum Member Platinum Member

    Aug 23, 2008
    This is an excellent comparison write-up @Fishcharmer .

    I appreciate the way you approached the topic with an open mind to gain practical information wherever that led. I like how you explained where each steel performs better. I like the fact that you stated a preference for A2 and why, while giving folks enough information to justify leaning toward 8670 depending on their uses.

    Thanks for taking the time to delve into a topic that is very relevant for this forum. It was an enjoyable read.

  6. Fishcharmer

    Fishcharmer Gold Member Gold Member

    Feb 1, 2020
    I think I'm in agreement on the advantages of tool steels, over super steels(for hunting). Because I just don't have enough practical experience with many of these super steels, I can't be certain, but given their "reported" characteristics, I would give tool steel the nod. I do know I want something that is not going to fail in BFE.

    I have observed that the same steel type, from different makers, doesn't always behave the same. That makes drawing definitive conclusions tough I think...I guess I'm just going to have to keep buying knives..:)

    Regarding the similarities among 8670, O1, and 80crv2:

    I have a lot more practical experience with O1, and think they are very similar. Tough, easy to put a good edge, and both require some after use care. I do think if I had to pick between those two for a hard use hunting knife, I would chose the 8670. I only have one knife (a sweet Leuku) in 80crv2. I just haven't used it enough to comment on it. Its reported characteristics would seem to indicate they are very similar. The steel 8670 reminds me the most of is L6. I have a couple of little skinners in L6 that have been put through the ringer over the years, and have done a marvelous job.
    rileybassman1 likes this.
  7. Fishcharmer

    Fishcharmer Gold Member Gold Member

    Feb 1, 2020
    Couldn't agree more on the "all-around" nature of A2. It just works, and at the end of the day that's what I want.

    Those are my observations as well with 8670. It really is a well balanced steel. Like you, I don't need my hunting knives shaving sharp, and given how quick and easy it is to touch up the edge, it really lends itself to that (hunting) application.

    Going with the prettier handle is sound advice..
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  8. Fishcharmer

    Fishcharmer Gold Member Gold Member

    Feb 1, 2020
    Thanks. I agree.

    My experience with s35vn is limited to a couple of knives; both for the kitchen.


    They both get a lot of use, and I would agree with your observations. Very, very impressive knife steel.
  9. Fishcharmer

    Fishcharmer Gold Member Gold Member

    Feb 1, 2020
    Thanks @Comprehensivist .

    It's not an exaggeration to say fiddlebacks brought me here, but it was reviews like yours, and others, that kept me here. What a resource..I still go back and re-read them when I am considering buying a knife, or to compare models. Cheers..
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  10. James River

    James River Gold Member Gold Member

    Dec 14, 2019
    Great write up! Thanks for taking the time.
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  11. Choppaman

    Choppaman Gold Member Gold Member

    May 6, 2017
    @Fishcharmer Thank you for this info! Very cool write up and comparison. Well done! The best part is you had a Strebig in the mix!! LOL :D:D:D Thanks for sharing such great information!!!
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  12. swonut

    swonut KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jan 1, 2007
    Thanks for the comparison and the thought that went into it. Knives are hard to compare since like you mentioned there are just so many variables.
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  13. B Griffin

    B Griffin Gold Member Gold Member

    Dec 22, 2007
    Thanks for the information. I've heard the 8670 is pretty tough. A local knife making friend of mine, who buys his supplies from Pop's as well, and I are in discussions of him making a model I designed. One I want that suits my current work situation out of 8670, and see how it does versus rough use against synthetic materials in an urbanized environment, so I can gain a better understanding of the steel myself.
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