D-2 or A-2 Opinions please?

Gentlemen

May your women appreciate you for being the Studs that you are!:D

Wow, that is some great info! I really appreciate it.

Let me draw some conclusions and see if I understand what all you fellas are saying.

1. It is likely that in the heat treating process there is enough room for error with either steel that we could negate any advantage one of the steels may have over another?

2. If I could maximize the qualities of the steel, the A2 will be easier to sharpen, will take more abuse lets say in using a baton, and though it is less wear resistance, in the field I am less likely to suffer major damage to the blade? I assume in must cutting situations the A2 will fall behind the D2, but if say cutting bone, or using a baton, it is less likely to break off a significant portion of the blade edge?

3. D2 shines best in the die room wear there is metal on metal, wear as it may fall behind A2 in the field wear you may be using your knife as a bit of a pry tool, or delivering heavy impacts to the back of the blade?

It sounds to me like D2 may not be as stable in a torsional sense, or in taking impacts due to the particle sizes in the steel. Would this imply that it is more brittle?

Thanks so much Guys!!!
AI
 
Agent Iron said:
Gentlemen

May your women appreciate you for being the Studs that you are!:D

Wow, that is some great info! I really appreciate it.

Let me draw some conclusions and see if I understand what all you fellas are saying.

1. It is likely that in the heat treating process there is enough room for error with either steel that we could negate any advantage one of the steels may have over another?

2. If I could maximize the qualities of the steel, the A2 will be easier to sharpen, will take more abuse lets say in using a baton, and though it is less wear resistance, in the field I am less likely to suffer major damage to the blade? I assume in must cutting situations the A2 will fall behind the D2, but if say cutting bone, or using a baton, it is less likely to break off a significant portion of the blade edge?

3. D2 shines best in the die room wear there is metal on metal, wear as it may fall behind A2 in the field wear you may be using your knife as a bit of a pry tool, or delivering heavy impacts to the back of the blade?

It sounds to me like D2 may not be as stable in a torsional sense, or in taking impacts due to the particle sizes in the steel. Would this imply that it is more brittle?

Thanks so much Guys!!!
AI
Click to expand...

Don't use the "B word" (br*ttle) around here...you'll get some people very excited.:D
For a general purpose, wood chopping, wood splitting, dirt digging, can opening, tent stake removing (just kidding, guys), etc. "survival knife", A2 will outshine, D2. (generally speaking, of course.)
Disclaimer: You should never use your knife for prying.:D
- Mitch
 
Well, I held off on replying to your post last night, but I wanted to chime in here with my thoughts.

I think A-2 is a better choice for an all around beater knife, especially if you plan to have it ground thin. That being said, I don't agree that A-2 will outshine D-2 generally speaking. I believe it will outshine D-2 in the sense that you can abuse it and beat the hell out of it without as much risk of chipping and or cracking.

Imo, you're right about D-2 being more susceptible to torsional and side loads, in thin cross sections. I like A-2 for larger knives that will be used for impact and prying, I like D-2 for smaller knives that will be used more exclusively for cutting.

After all that, I'd like to disclaim that a very good friend and experienced knifemaker disagrees with me on this and has told me as much. At the end of the day, you're not all that likely to ruin either one if it's heat treated well.

By the way, I don't believe that there's enough margin of error in heat treat that the steel properties are a wash. If your friend is a machinist familiar with these steels you should have no problem getting the most out of either.
 
Sorry about the "B" word. No offense intended. I actually mentioned to my brother in law that we should make a knife out of D2 and A2 for each of us. That would be a great test, and likely they would last us the rest of our lives anyway.

He does seem expert at heat treating, although as was mentioned by Nathan the Machinist that their may be subtle differences in the heating and cooling with respect to a knife compared to a die.

We will have to do more research before we begin.

Man you guys are a wealth of knowledge!

Here is a question. Are there certain commercialy or custom made knives or brands that you fellas trust as far a heat treating D2 and A2? I don't know but have reason to doubt that Ontario's heat treating of their D2 knives may be different then Cold Steel or some other brand. Is there something you can go on from their literature, or is it only experience that would dictate the quality of the heat treat?
Thanks again
AI
 
AcridSaint said:
Well, I held off on replying to your post last night, but I wanted to chime in here with my thoughts.

I think A-2 is a better choice for an all around beater knife, especially if you plan to have it ground thin. That being said, I don't agree that A-2 will outshine D-2 generally speaking. I believe it will outshine D-2 in the sense that you can abuse it and beat the hell out of it without as much risk of chipping and or cracking.

Imo, you're right about D-2 being more susceptible to torsional and side loads, in thin cross sections. I like A-2 for larger knives that will be used for impact and prying, I like D-2 for smaller knives that will be used more exclusively for cutting.

After all that, I'd like to disclaim that a very good friend and experienced knifemaker disagrees with me on this and has told me as much. At the end of the day, you're not all that likely to ruin either one if it's heat treated well.

By the way, I don't believe that there's enough margin of error in heat treat that the steel properties are a wash. If your friend is a machinist familiar with these steels you should have no problem getting the most out of either.
Click to expand...
Gee. It sound like you're agreeing with me. Hmmm...it must be the word I used.:)
- Mitch
 
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Taken from: http://www.crucibleservice.com/products/cutlery.cfm
 
Agent Iron said:
Sorry about the "B" word. No offense intended. I actually mentioned to my brother in law that we should make a knife out of D2 and A2 for each of us. That would be a great test, and likely they would last us the rest of our lives anyway.

He does seem expert at heat treating, although as was mentioned by Nathan the Machinist that their may be subtle differences in the heating and cooling with respect to a knife compared to a die.

We will have to do more research before we begin.

Man you guys are a wealth of knowledge!

Here is a question. Are there certain commercialy or custom made knives or brands that you fellas trust as far a heat treating D2 and A2? I don't know but have reason to doubt that Ontario's heat treating of their D2 knives may be different then Cold Steel or some other brand. Is there something you can go on from their literature, or is it only experience that would dictate the quality of the heat treat?
Thanks again
AI
Click to expand...

Just kidding around with the "B-word". No need to apologize.;)
- Mitch
 
Troop said:
Gee. It sound like you're agreeing with me. Hmmm...it must be the word I used.:)
- Mitch
Click to expand...

Troop said:
For a general purpose, wood chopping, wood splitting, dirt digging, can opening, tent stake removing (just kidding, guys), etc. "survival knife", A2 will outshine, D2. (generally speaking, of course.)
Click to expand...

Mitch - I am far from agreeing with you, as a matter of fact, I don't agree with just about everything you say in regards to A-2. I don't believe that heavy twisting, side loads and impact are "general purpose" nor do I believe that A-2 outshines D-2 in the area that matters most - being a *knife*. As a screwdriver, axe, prybar, etc, A-2 would probably work better, but as a cutting tool, D-2 is going to take the cake.

In all honesty, I don't agree with the way you work and heat treat A-2 and I don't believe that you have any real basis for your opinions beyond "gut feeling" and generally hype.

If I'm going to do a lot of cutting, I'd love to have D-2. If I want to cut open cans, I'd prefer D-2, if I want to chop or split wood, I'd have no problems with D-2 as long as it's not ground thin. The only reason I like A-2 for for this style of knife is because of the possibility of impact, torsional and side loads. Depending on how the knife is designed, this isn't even a signifcant issue.

Under normal use as a knife, even an outdoors, survival type knife, the D-2 is generally going to outshine the A-2, imo. Although the D-2 has a higher risk of breaking our blowing out at the edge, I don't feel that it is a significant one. That's why I didn't have any problems sending a good sized D-2 fighter with a friend on deployment recently.

I should add that the stain resistance of D-2 is a plus in a general purpose outdoors/survival type knife where the blade may not get cared for properly. Rust dulls steel rather quickly and a knife that gets abused in the woods may end up with just that.
 
AcridSaint said:
Mitch - I am far from agreeing with you, as a matter of fact, I don't agree with just about everything you say in regards to A-2. I don't believe that heavy twisting, side loads and impact are "general purpose" nor do I believe that A-2 outshines D-2 in the area that matters most - being a *knife*. As a screwdriver, axe, prybar, etc, A-2 would probably work better, but as a cutting tool, D-2 is going to take the cake.

In all honesty, I don't agree with the way you work and heat treat A-2 and I don't believe that you have any real basis for your opinions beyond "gut feeling" and generally hype.

If I'm going to do a lot of cutting, I'd love to have D-2. If I want to cut open cans, I'd prefer D-2, if I want to chop or split wood, I'd have no problems with D-2 as long as it's not ground thin. The only reason I like A-2 for for this style of knife is because of the possibility of impact, torsional and side loads. Depending on how the knife is designed, this isn't even a signifcant issue.

Under normal use as a knife, even an outdoors, survival type knife, the D-2 is generally going to outshine the A-2, imo. Although the D-2 has a higher risk of breaking our blowing out at the edge, I don't feel that it is a significant one. That's why I didn't have any problems sending a good sized D-2 fighter with a friend on deployment recently.

I should add that the stain resistance of D-2 is a plus in a general purpose outdoors/survival type knife where the blade may not get cared for properly. Rust dulls steel rather quickly and a knife that gets abused in the woods may end up with just that.
Click to expand...

It's all good, brother.:thumbup:;)
 
I'll throw something else into the pot CPM D-2. Better especially transverse impact and torsion ! LOLLOLLOL. Bob Dozier is considered the master when it comes to making D-2 knives .
 
Did Bob Dozier have any dealing with the steel on the Ka bar knives by his name? They seem so reasonably priced to have his name and to have him work the steel. Any opinions on the Ka bar's in D2?
Thanks
AI
 
Gosh darn I was going to try and stay out of the "which ones better" debate but I can resist no longer. I keep hearing about D2 in thin sections being brittle. AgentIron is making a "durable all purpose survival chore type of blade" which should probably have flat ground or convex ground geometry. IMHO, D2 would be an excellent choice both for its edge holding ability and its corrosion resistance, and I've used litterally, a ton of A2, I love the material for knives . If I had to choose between A2 or D2 for the type of knife we're talking about though, I think 3/16" or 1/4" D2 would be my choice. D2 with almost flat but definative convex ground bevels. Not sharp like an axe geometry, sharp like a knife geometry, geometry, geometry, geometry. Is there an echo in here ;) You will be able to baton the crap right out of a D2 blade @ 59/60 HRC with the proper geometry ...... IMHO :D
 
David Wesner said:
Gosh darn I was going to try and stay out of the "which ones better" debate but I can resist no longer. I keep hearing about D2 in thin sections being brittle. AgentIron is making a "durable all purpose survival chore type of blade" which should probably have flat ground or convex ground geometry. IMHO, D2 would be an excellent choice

snip

You will be able to baton the crap right out of a D2 blade @ 59/60 HRC with the proper geometry ...... IMHO :D
Click to expand...



Hey Dave,

I recently chopped through a 1/4" brass rod with a relatively thin, very hard (~63 HRC) D2 skinner design with one large hammer blow. No real damage. It lost its razor edge in that spot, but it really wasn't messed up at all. And it didn't break, and that was a hell of a blow. Did some small iron nails too. Yeah, D2 is tough enough. Tougher than some people think.
 
Simple words...both are great steels, I have and still make both but I think the D2 will be your answer.
 
Man, you guys are making me really itchy to try working with D2. Thanks for the extra motivation.:thumbup:
- Mitch
 
Im not sure guys... I think that their is no clear winner here...

A2 is pretty good too. It has great toughness and better edge retention than 01.

I think this discussing has gone from "what is a great steel for an outdoor knife?" to the brittleness of D2.
 
Keith_H said:
Im not sure guys... I think that their is no clear winner here...

A2 is pretty good too. It has great toughness and better edge retention than 01.

I think this discussing has gone from "what is a great steel for an outdoor knife?" to the brittleness of D2.
Click to expand...


Yeah, for an outdoor knife the abrasion resistance advantage of D2 is largely of little value. That type of use requires edge stability, which is more a function of heat treat and geometry (damn it's getting redundant, everybody saying that). In this application I think the question boils down to personal preference: is the stain resistance of D2 worth the additional time required to sharpen it?

Now, to add fuel to the fire, here is something I posted a little while back. It's relevant:


Relative strength of different steels

--------------------------------------------------------------------------------

snip


D2 is very strong, with a yield strength of 319,000 PSI at 62 HRC.
That is 2.5 times stronger than 6-4 AL-V titanium, at less than twice the weight. Yup, better strength to weight than Ti

440A AKA "Surgical steel" peaks out at 229,000 PSI at 54 HRC

D2 @ 55 HRC is 270,000 PSI
A2 and O1 @ 55 HRC are both 261,000 PSI

At least according to Bohler-Uddeholm.

Just thought I'd share...
 
Nathan the Machinist said:
Hey Dave,

I recently chopped through a 1/4" brass rod with a relatively thin, very hard (~63 HRC) D2 skinner design with one large hammer blow. No real damage. It lost its razor edge in that spot, but it really wasn't messed up at all. And it didn't break, and that was a hell of a blow. Did some small iron nails too. Yeah, D2 is tough enough. Tougher than some people think.
Click to expand...

I'll be the first to admit, the feedback I offer is usually never the technical, statistically backed up post that you'll get from Mete, Fitzo, Nathan or Kevin. :o ;)

Agent Iron, the 2 types of steels you're considering are both, IMHO, Excellent & Excellent . You can't go wrong with either one.
 
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