Comments on A2 steel

[ejt]

Wow, has this thread wandered from your original questions!

You asked about A2. If you want to know what everyone thinks about it - we need to know, compared to what? Mild carbon steel? Ceramic?

A2 shares many characteristics with D2, and D2 is well-recognized in the industry, so it's probably a useful reference for comparison. They are both relatively high alloy tool steels, from similar design criteria, and thus provide a kinda apples-to-apples comparison. Some of the earlier posts noted teh importance of knowing exactly what you compare it to. Yep, point of reference makes all the difference. A 3-step ladder doesn't seem short when you're lying next to it on the kitchen floor on your back looking up at it.

All other things being equal (and that seems to be where many of these posts headed off!), you should find A2 easier to grind, a little more resistant to chipping, and a little less wear resistant, than D2. In general, although it offers better resistance to impact breakage in laboratory tests (and we won't argue their relevance here) you should probably consider them to be cousins from the same family. Similar design steels, similar intended applications, A2 is a lttle less brittle, but a little less wear resistant as well. You're still working with a high hardness tool steel, not a spring steel.

A2 is not a stain-resistant steel by any stretch. If you need stain resistance, you're better off with stainless or non-ferrous (talonite etc)materials.

 

[Cliff Stamp]

Will :

I don't think Cliff meant to imply anything about the integrity of Jerry's construction per se ...

Yes, there are always tradeoffs for performance which is why you can't simply build the complete "best" knife. In any comparitive review, you could easily promote either blade by restricting the work to what would be optimal for that knife, this is promotional hype if done intentionally, but often it is simply being ignorant of an area of work and thus just not realizing the positive potential of an aspect.

Elwin :

[materials test vs actual blade usage]

The trick is knowing how to apply one to the other.

Yes, this is the complicated part. If I take a knife that you have used extensively and increase its RC, you should be able to predict how its edge retention will be effected. However if I decrease the RC and increase the wear resistance, it becomes difficult. There are counteracting effects and you have to know to what extent they control edge retention to predict the overall effect, and to make matters worse, this will be different for various types of work. My point isn't that you should just do materials tests. It is obvious that a complement to this is the necessary actual blade work. What I would like to see more of is a correlation made between the two, to promote an understanding of where the performance comes from which would allow a more rapid progresson in developments of blade materials.

I think there is something to be said for simple magnitude of the feat performed.

I judge an event (test / whatever) based on what knives can do it. For example, a high push shaving sharpness isn't impressive, even though many promote it as a sign of quality, as I have seen that on the cheapest of knives. After working with many high quality makers over the past few years, I now demand much more out of a knife than I used to, quite simply because I know it can be achieved. If for example I had not worked with ABS class bowies my perspective on the cutting performance of a large chopping knife would be radically different than it is now. Fixed judgements on tests can lead towards hype when they ignore performance baselines as they can promote something as being difficult when in reality it is not. A common example of this is the Cold Steel car stab. Cold Steel has managed to convince people that this is very difficult, and thus implies high performance. I have in fact even seen makers comment that it is abusive. In reality even very low class knives can do it easily as you are just poking through mild steel. This exact same perspective should be used when judging steel. Blanket statements are meaningless, you need to reference relative terms just as ejt noted.

-Cliff