Cryo vs Non Cryo

[Eddie Darby]

A while back I got a flyer from my Lee Valley Tools monthly supplement discussing that there may be no improvement in either A-2 blade treatments, and that a follow-up would be coming along with the findings of the study.

Did I miss something here? I haven't seen anything, and it's been a while.

I wonder if there are plane users here that have both company's blades and can offer their opinion on what they personally find regarding the A-2 Cryo and Non Cryo A-2 blades.

Thanks

[Frank Desaulniers]

Hi Eddie,
No answers yet...gee! It's a controversial subject and the info I've read is all over the map. Wish I was an expert and could give an informed opinion but I'm not. It's claimed that cryo treatment changes the crystal structure of the metal and makes the carbide particles smaller, that it reduced internal stresses, and that it reduces austenite content (transforms softer austenite to harder martinsite) and disperses fine carbides within the martensite); others say it has no effect. Still others say that blade and tool sellers use it as a marketing tool rather than as a means to improve their tools.
I do know that some companies spend a lot of money to cryogenically treat tooling parts (dies, cutting tools); why would they do this if it had no effect?
My own experience is unfortunately very limited. I've tried A2 blades from only 2 companies (several blades from each comany, though), one of which treats their blades cryogenically (Lie-Nielsen). They happen to be my favorite blades, but my sample is too small to draw any conclusions (impossible for me to tell whether the cryo makes the difference, or whether the heat treatment or some other factor accounts for the differences in the way the blades behave). IME they hold an edge longer.

[Rob Millard]

Eddie,
I don’t have any blades from Lee Valley, but I do have several A-2 irons; some cyro treated and some not. The non treated ones were custom made a few years ago at a machine shop, I worked at. The others are From Lie-Nielsen. I see no advantage to the treated irons. In fact the ones I had made preformed better right from heat-treat than the LN irons. A few of the LN irons required grinding back about 1/64-1/32” before they would hold an edge. I suspected that this was from surface grinding after heat-treat, but it may have been due to the cyro treating. After grinding though, the LN's have worked great.
Rob Millard

[Fred Krow]

There is two generally accepted methods of cryo heat treating.

The most common is liquid nitrogen at -100 degrees F, this has been done for many years to transform retained Austenite to Martensite.

The more expensive is -300 degrees F, this is the method that will change the structure of the carbides and give longer wear life to tooling. This is a 24-36 hour process with slow cooling and slow recovery to temp. and then a secondary temper is used at approx 300F to 400 F depending upon the alloy. The -300F is used for brass musical instruments, razor blades last 4x-5x longer, target rifle barrels exhibit 2x-3x longer life. Racing car engine parts last significantly longer,,,,this process in not only for high alloy hardened parts.

Does cryo heat treatment make a difference with A2 or O1 wood cutting tools ? I belive only LV has done any comparison testing and they claim no improvement in edge life. Was the A2 Cryo process the -100F or -300F ?

Regards,
Fred Krow

[Jerry Palmer]

The process of sharpening is a process of wearing away metal. Once again, a trade-off, just like going from old W1 to regular A2. While you may gain in longevity, at least a good portion of what you gain is lost in the additional time spent wearing away metal to get a new edge.

When I renew an edge on one of my vintage blades, it generally takes less than a couple minutes on my two finest water stones. When the A2 blade of my Knight Smoother is in need of a touch-up, it takes three or four times as along with an equal width secondary bevel. Admittedly, because of the work I'm asking the Knight blade to do, I'm rehoning it with significantly less wear to the edge than with other planes used for more crude work, the added longevity of edge is there, but I don't believe I'm getting three or four times as much use between honings. I may start the rehoning with a medium stone on the A2 blade just to get a wire edge to insure I'm on the secondary bevel because that blade is so much thicker than the others, so that does account for a little extra time, a dozen or so strokes, maybe.

[Tom Sontag]

Fred's answer is a much better one than I would have been able to give, but it is along the lines of what I have heard and read. The cryo treatment does not affect hardness as much as toughness (ability to hold an edge). I was given a thumbs up on cryo just this weekend from Alan Lacer, woodturner and second or third generation metal worker. I believe.

[Fred Krow]

Knight smoother,,, I may start the rehoning with a medium stone on the A2 blade

Jerry,

I have two Knight smoothers (45 degree & 50 degree) they both have O-1 tool steel blades.

I was not aware that Steve had A-2 blades available?

Regards,
Fred Krow

[Eddie Darby]

There is two generally accepted methods of cryo heat treating.

Does cryo heat treatment make a difference with A2 or O1 wood cutting tools ? I belive only LV has done any comparison testing and they claim no improvement in edge life. Was the A2 Cryo process the -100F or -300F ?

Regards,
Fred Krow

Thanks for the information. I didn't know that there was another treatment that involved only -100 F.

Did Lee Valley publish their findings that said there was no difference, and if so do they say what treatment they tested?

[Jerry Palmer]

Jerry,

I have two Knight smoothers (45 degree & 50 degree) they both have O-1 tool steel blades.

I was not aware that Steve had A-2 blades available?

Regards,
Fred Krow

Hmmm? Just went and checked his site and it seems you are correct on that. Don't know where I got the idea that it was A2. :o

[Fred Krow]

The long discussion involving heat treatment and Cryo was on Woodcentral in October 2004 ref:

http://woodcentral.com.ldh0138.uslec.net/cgi-bin/archives_handtools.pl?read=47643

Rob Lee did not commit to the exact cryo process however, LV did an extensive comparison test with many blades. I suspect that LV is cost sensitive and did not use the expensive -300 F process,,,,,just my personal guess.

We do not know which cryo process is used by LN or Hock with their blades.



Regards,
Fred Krow

[Eddie Darby]

The first casualty of war is the truth, and I guess that is the case here as well as I am sure that if someone does a study and finds something that would help the other guy, then it's better not to say anything. So I was hoping that people would come forth with their own experiences to help decide the matter, from a consumers point of view.

I don't really care about the Placebo Effect since it too is real. If you are sick, and a sugar pill heals you then you are healed! Maybe Grandma put sugar into the chicken soup as well! If it works it works!

So if you think you are better off with Cryo or Non-Cryo then I would think you would know better than anyone else!

[Clinton Findlay]

I do know that some companies spend a lot of money to cryogenically treat tooling parts (dies, cutting tools); why would they do this if it had no effect?


if it has no effect on the iron, or if it has no effect on sales? :rolleyes:
Two very different things.

[Travis Johnson]

For ethical reasons I cannot get into the debate regarding this type of blade treatment, but it should be noted that Lie Nielsen uses the -300 degree cyrogentic treatment method, not the -100 degree treatment.

[Frank Desaulniers]

if it has no effect on the iron, or if it has no effect on sales? :rolleyes:
Two very different things.
If it has no effect on steel and the durability of their tooling. When I talk about companies that make dies and cutting tools I don't mean plane blades but industrial cutters of all kinds. These companies sell what they make with their tooling, not their tooling. As Fred indicated cryo treatment does apparently have an effect.

[Alan DuBoff]

Hmmm? Just went and checked his site and it seems you are correct on that. Don't know where I got the idea that it was A2. :oJerry,

Steve offers an upgrade to a Japanese blade, which is probably what you confused it with.

Yesterday was my 4 months anniversay from ordering a plane from Steve. I hope he gets it done sometime. I guess you really have to order these far enough in advance that you really don't need to use them or have to use them for a long, long time...:( The 2nd plane is only just over 3 months, and was evidentally finished a few weeks ago...but I haven't seen either of them...<sigh>

[Rob Lee]

(snip)

Rob Lee did not commit to the exact cryo process however, LV did an extensive comparison test with many blades. I suspect that LV is cost sensitive and did not use the expensive -300 F process,,,,,just my personal guess. (snip)





Hi Fred -

We used other peoples cryo blades too...and still could find no difference.

No matter what the cryo process - we could find no benefit for properly treated A2...

If we thought it did something - we'd use it; after all, it's just a subcontracted additional process...

Cheers -

Rob

[John Downey]

Surely, somebody somewhere understands the thermodynamics of this? I'm certainly no expert on the subject, but based on the little I remember of it, I'd be fairly surprised if cryo treatment were proven to have any benifit. Given the lack of choice in the general marketplace between cryo treated A2 tools and non-cryo treated A2 tools (anyone know of any?), its all kind of acedemic.

John

[Mike Wenzloff]

There's cyro'd plane blades and chisels as far as the typical woodworker can get. LN is one source.

When I was involved in other tooling, cyro treatments were available on large cutters being made from exotic metals.

As to the science and its efficacy, I defer to Rob. I've never seen a difference in edge tool longevity, metal for metal, as regards its practical application in a wood shop.

Take care, Mike

[John Downey]

Sure, tons of cryo'd A2 available. But I'm not sure I could name anyone selling non-cryo A2 tools.

I forgot to add, I've noticed something similar to what Rob Millard described with poor edge retention in the factory edge that gets better after being sharpened back a bit. I never thought
about it being related to post treating grinding though. It does make me wonder how fragile the treatment is, as I think a lot of us assume that air hardening steels are like HSS and close to indestructable. Not really trying to make a point here, just pondering out loud.

John

[Mike Wenzloff]

LV's A2 is non-cyro.

Blue Spruce A2 chisels are non-cyro. They hold a wonderful edge, even when honed at a lower than 30 degree angle.

Your and Rob Millard's experience echos mine as well. Even less expensive HC edge tools such as my Sorby paring chisels got much better after I ground them back maybe an 1/8" or so.

I've come to regarding heat treatment a bit of voodoo and science, at least with the air hardening steels. O1 is pretty simple that even I can do it. Heck, I'm making some floats from O1. First one I made as a trial turned out great. Too bad I didn't make a full sized one...

Take care, Mike