How brittle is D2?

Sharpening D2 and CPM D2 was no problem on DMT's and Shapton Glasstones for me. I had always heard the "takes a terrible edge and holds it forever" thing, but they got plenty sharp for me, and for slicing rope they had good edge retention. They both took an aggressive edge on the DMT's that would shave nicely and polished out to tree topping and free hanging hair cutting edges on the Shapton's. With lapping films they whittled hair like a champ. I never got a chance to test their edge retention when polished, but I would probably leave my edge more on the coarse side and use a D2 knife as a long term slicer if I had one (I really want a Krein Ultimate Caper).

I also used the Edge Pro on the CPM D2 and other knives and what Thom said is completely true to my experience. The 600 stone seemed closer to my Shapton 2000 in terms of the finish, as it tree topped hairs with all of the knives I tried on it. Then I got to the lapping films on the Edge Pro for the really fun .3 micron showoff edges. It is a good system that will give you consistently good edges, where my free handing can get knives just as sharp as the Edge Pro when I'm on, but on off days I can't match the Edge Pro. I still prefer free handing, though the consistency of the Edge Pro is nice to have.

Mike
 
Hi AG, Anyone who was around Bladeforums when Turber ran it has some idea of why Spark would be annoyed by Cliff's comment. I had occasion to talk with him on the phone and he pissed me off on that first call. On the other hand it seems like a double standard to ban Cliff for his critical comment (( references out of proper area ))

All this hoopla is just over words typed on a computer. One of the reasons that I liked Bladeforums is that it represents independent voices rather than corporate marketing hype or PC niceness. Some interesting information comes out of the conversational volleys. I gave up on Knifeforums when it seemed like they were too deferential to their sponsors. I hope that it never gets too "nice" around here for people to be candid.
 
Speaking of D2, this arrived today!

Charles May FireAnt in D2 and Tan Micarta.

FireAnt-Micarta-1.jpg


Initial review, is its a typical Charlie May, cleanly done and wicked sharp!
 
I had always heard the "takes a terrible edge and holds it forever" thing,
Click to expand...

That unfortunately is often what is repeated. A truer statement I think is that it holds a crappy edge forever, which is not saying it can't get scary sharp. We sure know different than that. That statement about holding a crappy edge is not an insult it only refers to after someone has taken a good D2 blade and used it reducing that scary sharpness to a commonly seen end line user crappy edge which will be that way an incredible amount of time for most folks that are used to a cheaper bottom of the barrel steel such as a Taiwan or China made knife of something you have no idea about what it is but that it just doesn't cut for very long even when it is crappy. But some of these crap knives are all most end line users really deserve to be carrying when you see what they do with their knives too, however that is another story perhaps for another thread.:D


STR
 
The Last Confederate said:
Speaking of D2, this arrived today!

Charles May FireAnt in D2 and Tan Micarta.

FireAnt-Micarta-1.jpg


Initial review, is its a typical Charlie May, cleanly done and wicked sharp!
Click to expand...

I have several Charles May's knives and they really are GREAT little knives. Charles knows how to do D-2 that is for sure!!

Tom
 
STR said:
One thing about D2 that I would like to know from some of the makers besides Bob is their feelings on Cryo and D2. Do you use it? Surely it adds some toughness yes??? I'm just curious because I know Bob's feelings on it, however I don't know myself which side of the fence I'm on about it personally. Both sides make sense but..... and thats where I'll leave off.

STR
Click to expand...

First I would like to say Bob Dozier knows more about knifemaking and metalurgy than just about anyone I know! It was my pleasure to work under Bob for 3+ years! I highly respect Bob's knowledge and knifemaking skills!

I have seen the books on metallurgy and heat treatment that Bob has read and studied! I have seen him on the phone with metallurgists for hours at a time. Bob knows D-2!! If you doubt that you have not been paying attention, and Bob doesn't think cryo is necessary!!

From what I understand about Cyogenics and steel, the process helps some steels much more than others. When D-2 is heat treated spot on it gains very little from cryo, it does benifit slightly but not much. This is just what I have gleaned from talking with Crucible and Bob.

I personally send my blades to Paul Bos for heat treatment. I just don't have the specialized equipment needed to do the job in shop. Paul cryo's all of my blades and while it may not help D-2 much it surely doesn't hurt and maybe gives them a slight touch more of toughness.

The end result is what matters and I don't hear any of Bob's customers complaining about their edge retention or cutting ability... My conclusion is that cryo with D-2 is something that is not necessary with a spot on heat treatment, but I figure it can't hurt and might even help a little...


Tom
 
here's an article on cryo tests done on A2

http://www.google.com/url?sa=t&ct=r...pa7AvZbj4YhqQfnLQ&sig2=FnN8xF142rfvttYYxitrYQ

impact toughness went down with cryo, but wear resistance & hardness went up. In the Heat Treater's Guide, there is a small section on cold & cryo treating. Again, it mentions converting retained austenite to martensite, increasing hardness. A table for wear resistance increase for cold (-120F) & cryo (-310F) is presented, too. D2 goes from 224 untreated to 304 cold & 878 with cryo.

I've seen increased toughness mentioned as a benefit of cryo, but never seen anything about it. Maybe it's just the reduced internal stress helping to minimize cracking?
 
Custom knife makers currently using D2 as a staple in their steel line up (please feel free to add or delete) :o

Bob Dozier
Tom Krein
Charles May
Gene Ingram
David Winston
(see a pattern, imho, of well designed/made knives?)

Thanks AG Russell and Tom Krein and any other makers or authorities for posting here. I think it serves a larger purpose when those of your stature post in such a thread to educate. :)
 
Well I'm going to show off my new D2 fighter by Hatfield Knives.
6 inch blade.
It was in the mail when I started reading this "Brittle" crap.
Had me worried for a second.
47b7d726b3127cce98548bc05a1800000027108AcuGrdu3cNU

47b7d726b3127cce98548bcfdb2700000027108AcuGrdu3cNU
 
Thanks Tom. Good info and I appreciate it. I also feel the same way about Bob and his knowledge. I've never had any of the D2 blades I did for myself cryo treated and have not had any problems with them but was just curious.

Some seem to think it made the difference between the Safari Skinner performance and the Agent but of course the source of this info spoke highly of possible bias too or at least it entered my mind. Far be it from me to know though. I just wanted thoughts on it. Hearing that Paul Bos is doing the cryo with D2 and that Bob Dozier isn't does not make for a clear cut case though now does it? ;) Two authorities with differing views.

I think I've read every last word of Bob's about this on his forum but I have no where to see Pauls. One day I may have to ask him since I do on occasion send something his way also.

STR
 
ADD said:
Custom knife makers currently using D2 as a staple in their steel line up (please feel free to add or delete) :o

Bob Dozier
Tom Krein
Charles May
Gene Ingram
David Winston
(see a pattern, imho, of well designed/made knives?)

Thanks AG Russell and Tom Krein and any other makers or authorities for posting here. I think it serves a larger purpose when those of your stature post in such a thread to educate. :)
Click to expand...

WT FULLER no longer with us, but always told me, D2 was hard to beat as a material to work with and last. I have many of his knives and I believed him, he was one of the greats.
 
ADD said:
Custom knife makers currently using D2 as a staple in their steel line up (please feel free to add or delete) :o

Bob Dozier
Tom Krein
Charles May
Gene Ingram
David Winston
(see a pattern, imho, of well designed/made knives?)

Thanks AG Russell and Tom Krein and any other makers or authorities for posting here. I think it serves a larger purpose when those of your stature post in such a thread to educate. :)
Click to expand...

Thank you, sir! You've saved me considerable time.
 
ADD said:
Custom knife makers currently using D2 as a staple in their steel line up (please feel free to add or delete) :o

Bob Dozier
Tom Krein
Charles May
Gene Ingram
David Winston
(see a pattern, imho, of well designed/made knives?)
Click to expand...

Scott Gossman! :thumbup:
 
Jeff Cover too. I have one he is working on for me as I type and its in D2. Further his feelings about it are pretty much on par with ours posted here.

STR
 
STR, that lead I gave you must have worked out. I just received one of his and it is FINE. I know you will be pleased. I am!!:thumbup:

Jim

Sorry for diverting thread for a couple of post, Jim
 
Did I not get back to you? Oh, man my bad there. Yes. I called Jeff and spoke with him on the phone at length about my design and what I wanted to get and he was excited to help me with it and liked all my ideas. He works with D2 which I do like fine and I went with that through him for my 'working mans' folder design but I went to Tim Britton also for the same thing and Tim is working up one for me the same way in 1095 which I also plan to get. I also wrote Bob Ham for the same thing and have not heard back from him but depending on how spanned out these are there is a high probability I'll be getting three! One from each maker to my own specs. I am referring of course to this post I made in traditional forums for those of you lost to this slightly off topic post. http://www.bladeforums.com/forums/showthread.php?t=496518

Thanks James. Now we can get back off course. Sorry guys.

STR
 
thombrogan said:
Tom Krein,

That horrible saying about D2 is sorta true if you look at sharpness as not only the alignment and finish of the edge, but also its total included angle. That is, a spooky mirror-finished edge that's 8 degrees (4 per side) will be sharper than a 30 degree edge (15 per side) with the same level of finish and alignment.

Now that said, there are maybe 400 people on the planet who care about that sort of edge, nine of which post on the internet, and only three still post here. And with that said, having a knife with a 10 degree edge is the bizallz, but it gets overrated when you're slicing a bell pepper and it wedges in the stem and you have to get all of your food prep done in under 10 minutes or else risk rust (less time for acidic fruits like pineapple) and you can't use a plastic cutting board sheet or else you'll chip the blade.... Wouldn't want to think how it'd do on a hunting trip. :eek:

A very cultishly popular* chefs knife these days uses Hitachi's SKD-11 as its edge steel. SKD-11 is Hitachi's name for D2.

*= Not Shun/Henckels/Wusthoff popular - more 'obscure great movies' popular
Click to expand...

I guess I'm one of the three still posting who like those 8 degree edges still posting, but I only run it on my Takeda Aogami Super Steel Gyuto (some guy from the northeast recommended them to me, you might know him). Like you said though it is a pain in the ass to keep wiping off and drying the blade every couple minutes when making a meal, but the cutting ability is astounding. How is your cultishly popular SKD-11 knife comparing to your Takeda? Does the marginal deficit in cutting ability by the slightly thicker and more obtuse edge get overcome by the much superior corrosion resistance and additional toughness for your cooking?

Mike
 
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