A2 vs O1 steel - does it really matter

[Bill Winter]

I am thinking of buying a LN Small Chisel Plane. It is only available with an A2 blade. The research I've done indicates one can't get an A2 blade as sharp as an O1. Is this true and does it really make a difference?

[ken hatch]

I am thinking of buying a LN Small Chisel Plane. It is only available with an A2 blade. The research I've done indicates one can't get an A2 blade as sharp as an O1. Is this true and does it really make a difference?

Bill,

When metal meets wood, not much difference. Sharpening system used can make a difference but most is in preference. Full disclosure there is no A2 used in my shop.

ken

[Robert Hazelwood]

It's not my favorite steel but you can get it plenty sharp. Works better with synthetic waterstones, or something like a Spyderco ceramic. My main issue with it is that it seems to fail by tiny chipping at the edge instead of just gradually wearing smooth.

I think it would be fine for a tool like this that you are not going do a ton of work with. I have it my block plane and my LN spokeshave and it works fine there. I only felt compelled to swap it out on my #4 bench plane due to the microchipping.

[Ben Ellenberger]

I have a couple of A2 chisels and a lie-Nielsen block plane with an A2 blade. When I sharpen them and look at them under a bright light with magnification, I can convince myself that they look different than an O1 blade. They do feel different when sharpening than O1. When I use them, they work great. I would be perfectly happy using an A2 chisel plane. I’m curious to use A2 on a smoothing plane and see if it makes any visible difference on a finished surface.

I use diamond stones up to 1200, then polish on a black Arkansas stone. I notice Lie-Nielsen pushes water stones on their site. I’m curious if people who have tried different sharpening systems think they make a difference on A2.

[Jim Koepke]

Hi Bill,

There have been many discussions of this over the years.

Here is one from a little more than six years ago > https://sawmillcreek.org/showthread.php?219830

My three plane blades with A2 steel are easier to sharpen on water stones than on oilstones.

jtk

[David Bassett]

I am thinking of buying a LN Small Chisel Plane. It is only available with an A2 blade. The research I've done indicates one can't get an A2 blade as sharp as an O1. Is this true and does it really make a difference?

In theory, the guys with microscopes, tell us the A2 carbides leave a less refined edge with initial sharpness degrading quickly.

I think, in practice, most of us don't sharpen well enough to see that effect and will do just fine if our sharpening system can handle A2 (and it was well heat treated. As I trust L-N's to be.) Bottom line is expect to take a little longer to sharpen A2, expect it to lose it's "first stroke, just sharpened" edge sooner, but to keep an "OK working edge" for longer. Then judge how YMMV!

[Michael Fross]

In my experience, there is little difference in practice. LN makes fantastic irons. I have O1, A2, and PMv11 in the shop from different makers and all do a great job. I do use shapton waterstones exclusively, so I can't comment on the sharpening differences. I also use a 25 degree bevel and a small secondary bevel at about 30 degrees.

Michael

[Eric Rathhaus]

Robert - u should read all the info on wood central about the "unicorn" edge. Preventing edge chipping is one of reasons to give it a try.

[steven c newman]

Actually..I have not the foggiest idea what steel is in the tools I use.....other than those with a Chrome Vanadium stamped on them....nor have I noticed any differences....sharp is sharp....and as long as I can continue to get them sharp....that really is all that counts. Would much rather use the tools, than waste time off in the search of the "Perfect Edge".......

[Stephen Rosenthal]

Actually..I have not the foggiest idea what steel is in the tools I use.....other than those with a Chrome Vanadium stamped on them....nor have I noticed any differences....sharp is sharp....and as long as I can continue to get them sharp....that really is all that counts. Would much rather use the tools, than waste time off in the search of the "Perfect Edge".......

Couldn’t agree more!

[Andrew Hughes]

The last time I looked Lie Neilson didn't have any 01 irons available. I also like it to me it does getting a keener edge. But doesn't last as long as A2.
There's always a trade off. No such thing as a unicorn. Someone should tell David he can stop looking. 😀

[Curt Putnam]

O1 can take a more shallow / acute angle than can A2. At >=30° pretty much everything gets sharp and stays that for a usably long period. A2 has a reputation for not doing well at < 25° whereas O1 can get to 20° for paring work.

[Matthew Hills]

I've been happy with my LN A2 plane blades. I've never really wished for anything different. (I did pick up PMV11 blades on one or two LV planes, but I haven't used them enough to really appreciate a difference)

I've been happy with my LN chisels (also A2), although I sometimes wonder if I'd like O1 even more.

I've heard sharpening method may affect satisfaction with A2. I'm using sigma water stones.

Derek cohen has a couple of articles comparing chisel steels on his website: http://www.inthewoodshop.com/ToolReviews/index.html


Matt

[Jim Koepke]

O1 can take a more shallow / acute angle than can A2. At >=30° pretty much everything gets sharp and stays that for a usably long period. A2 has a reputation for not doing well at < 25° whereas O1 can get to 20° for paring work.

The range of optimum bevel angle is another factor in my choice of O1 steel for all but a few tools. My paring chisels start out off my electric sharpening system at 15º. Then get 'reground' when they stray much steeper.

My plane blades are mostly at 25º. Some are at 30º as are many of the flat side chisels.

There are a few PM v-11 blades in the shop and they seem to do okay on oilstones. Even though they have been used regularly they haven't had to be sharpened much. That is a good reason for them in itself.

The Veritas set of miniature chisels has me wanting to give them a try.

jtk

[Curt Putnam]

Jim, since the OP's question was A2 vs O1 I did not bring up the question of potentially superior steels, I think either will work well in a chisel plane.

[Doug Dawson]

There are a few PM v-11 blades in the shop and they seem to do okay on oilstones. Even though they have been used regularly they haven't had to be sharpened much. That is a good reason for them in itself.

I second the recommendation for Lee Valley’s PMV11 blades. They’re easier to sharpen to a fine edge than A2, and they seem to stay sharp longer than O1.

I guess that makes them a unicorn.

Plus, they’re packaged really nicely. After the apocalypse, you can trade them for food.

[John C Cox]

I don't think you will have any issues with a genuine LN iron. Those guys are very particular about their steel and heat treatment.

If this was a discussion of A2 vs O1 in general - my opinion would be:
It all depends on the maker. The thing I have learned about "Steel" edge tools is that the raw spec doesn't mean nearly as much as the maker... The maker does stuff like control the quality of incoming steel, the crystal structure, grain orientation, and proper completion of the heat treatment process... That's one of the reasons that some of the cheap import tools have awesome specs, but don't perform like you would expect given the pedigree of the materials highlighted in the marketing material...

I have no hesitation using a Hock, LN, or Veritas iron. Stanley irons are pretty good too. Other stuff, maybe not so much.

[Tony Zaffuto]

Actually..I have not the foggiest idea what steel is in the tools I use.....other than those with a Chrome Vanadium stamped on them....nor have I noticed any differences....sharp is sharp....and as long as I can continue to get them sharp....that really is all that counts. Would much rather use the tools, than waste time off in the search of the "Perfect Edge".......

I’m with Bandit on this! After using a tool, you become acclimated to its idiosyncrasies, including how hold, sharpen, etc. However when buying new, I would lean towards O1 or LV’s PM-V11, but my need of buying new edge tools has been pretty much zero over the past half dozen years.

[John Keeton]

I don’t have near the user experience with O1 vs A2 that most of you. Other than the vintage blades in various tools, I suspect most of the other blades in my modern planes are A2, though I don’t know that. But, I have changed out the blades in all my vintage spokeshaves to the PM V-11 and IMO it is a superior edge material. It seems to take a nice edge and hold it far longer that the blades in my other tools. The spokeshaves do get used much more than my other hand tools, with the exception of my vintage drawknives. I also like the A2 blades in the LN Boggs shaves, but I have the sense that the PM V-11 holds an edge noticeably longer.

[Bill Rhodus]

I am thinking of buying a LN Small Chisel Plane. It is only available with an A2 blade. The research I've done indicates one can't get an A2 blade as sharp as an O1. Is this true and does it really make a difference?

It really depends on your sharpening medium. If you use water stones you can sharpen both well. I have always used oil stones and have developed a routine to quickly grind/home the O1 that works well for me. I do not enjoy sharpening the S2 on oil stones as it takes longer to get an acceptable edge. Search thru some of the entries by Derek Cohen; good commentary there.

[Bill Rhodus]

It really depends on your sharpening medium. If you use water stones you can sharpen both well. I have always used oil stones and have developed a routine to quickly grind/home the O1 that works well for me. I do not enjoy sharpening the S2 on oil stones as it takes longer to get an acceptable edge. Search thru some of the entries by Derek Cohen; good commentary there.

Should have read A2 rather than S2.

[Larry Frank]

I hear all kinds of comments about these various steels. One needs to understand that steel grades have a range of chemistry. For example the carbon content of O-1 can vary from 0.85% to 1.00%. This can make a difference in properties. In addition, the production and heat treatment make a large variation in properties. Thinking that all A2 is the same would be risky as its heat treatment is quite complicated resulting in a range of properties.

[Jim Koepke]

I hear all kinds of comments about these various steels. One needs to understand that steel grades have a range of chemistry. For example the carbon content of O-1 can vary from 0.85% to 1.00%. This can make a difference in properties. In addition, the production and heat treatment make a large variation in properties. Thinking that all A2 is the same would be risky as its heat treatment is quite complicated resulting in a range of properties.

Larry, this is a good point. In discussions of various steels it is generally accepted the various steels are produced with controls to keep them in the range of qualities the customer is expecting. Someone may receive an A2 or O1 blade that is improperly heat treated and is extremely hard, soft or tends to chip. These are hopefully the outliers for any maker.

One of my Stanley O1 blades is incredibly hard compared to others from the same time period. There is no sense in holding it up as being an example of all others.

As a general rule, tools made of A2 steel are harder than those made of O1 steel. O1 steel is easier to work on oilstones than A2 steel. Some even feel it is advisable to use water stones with A2 steel for the best results.

jtk

[steven c newman]

All I ever ask of ANY edge tool....is that it stays sharp through the entire project I am working on....

Even 100 yr old irons...
447966
Couldn't care less what steel, or who sold it....I just need it to do the task I need done....

There always seems to be a bit of "downtime" between Projects.....I use that to refresh the sharps.....

[James Pallas]

I have the worst habits for a2 or Japanese chisels. I like low angles and tend to “dig” with chisels. If you follow the rules with a2 it will work for you just fine. Too chippy for my habits. Had some LN’s and gave them to a friend, I think he is still a friend. Beautifully made chisels, woodworker with bad habits.

[Rob Lee]

Hi -

Just another factor.....

From a manufacturing perspective - A2 is a lot more "friendly" to work with. O1 can move a lot when hardened.... making it more difficult to produce thin/narrow blades.

Cheers -

Rob

(who has more O1 blades than anything else....)

[Phil Mueller]

I had to chuckle a little at your comment, Steven, about sharpening during your “down time”. What is that...like 15 minutes? :D

[Andrew Pitonyak]

The last time I looked Lie Neilson didn't have any 01 irons available. I also like it to me it does getting a keener edge. But doesn't last as long as A2.
There's always a trade off. No such thing as a unicorn. Someone should tell David he can stop looking. 

Amazon begs to differ.... they sell Canned Unicorn meat.

https://www.amazon.com/Canned-Unicorn-Meat-Lunch-Spread/dp/B0781DKT3Z

[Charles Guest]

Fifteen or so years ago A2 in a woodworking tool was the Second Coming of Jesus Christ. Guys gushed like little girls - same ones that wouldn't be caught dead using it today. Same with Clark & Williams single iron smoothing planes pitched at 50*. They had so many orders it nearly put them out of business.

Moral: take everything with with a 5lb. sack of salt, not just a grain.

[ken hatch]

Fifteen or so years ago A2 in a woodworking tool was the Second Coming of Jesus Christ. Guys gushed like little girls - same ones that wouldn't be caught dead using it today. Same with Clark & Williams single iron smoothing planes pitched at 50*. They had so many orders it nearly put them out of business.

Moral: take everything with with a 5lb. sack of salt, not just a grain.

Charles,

I had to laugh, it is so true.

ken

[John C Cox]

It's sort of true, but it also ignores that those same people basically kicked off the resurgence of high end chisels we currently enjoy... So while perhaps A2 has it's limitations, it also allowed several vendors to justify the additional expense of tooling to create tools which many woodworkers really wanted. So while folks may criticize the alloy, Blue Spruce's paring chisels are the best designed new production paring chisels you can currently buy. Sure, Narex makes some that they call "Paring" chisels, but they're more like the older "Millwright" chisels - long, but thick and heavy. They don't have the light, sensitive feel of the old, thin octagon bolster Sorby or Marples paring chisels like the Blue Spruce units do.

[Jim Matthews]

Sure, Narex makes some that they call "Paring" chisels, but they're more like the older "Millwright" chisels - long, but thick and heavy. They don't have the light, sensitive feel of the old, thin octagon bolster Sorby or Marples paring chisels like the Blue Spruce units do.

Narex should be applauded for making small batch products at their prices. For a "slight" additional charge, anything is possible.

Making something well, and cheap -that's an accomplishment.

[Tony Zaffuto]

For modern paring chisels, I like the Robert Sorby (mine are a bit more than a dozen years old). The steel seems to be O1, and while many complain that the Sorbys have a habit of chipping, I have found that to not be true, after honing back a 1/16" or so. Being paring chisels, and only used as a paring chisel, I hone at approximately 20* (remember, these are used only as paring chisels and my approximate degree is because after I first established my bevel by a jig, I've free-handed ever since.).

[steven c newman]

Ah yes...The Riddle of Steel......

[Tony Zaffuto]

Ah yes...The Riddle of Steel......

And sharp trumps all!

[Andrew Pitonyak]

Ah yes...The Riddle of Steel......

https://conan.fandom.com/wiki/The_Riddle_of_Steel

[John C Cox]

It says something that there are seemingly large performance differences between various plane irons and chisels, because the alloys used on volume production stuff (not boutique/experimental) seems to fall within a fairly narrow range, except for a few outliers, notably A2 and PMV11.

And ironically, the performance seems to vary considerably depending on who is doing the test.

What that tells me is that by and large, the notable performance differences are largely either caused by tool preparation/sharpening procedure, and by the manufacturer's heat treatment protocols and QC requirements.

It made a lot more sense when I saw some videos of industrial high volume chisel production on an automated carousel... They perform the *entire* heat treatment process including tempering done in about 2-minutes. Then I looked at some alloy diagrams and saw that certain steel phase conversions have a time element.. And it all made sense. There's simply not enough time in the price of the cheap stuff to do any better on average.

[Larry Frank]

Some of these new alloys such as A-2, have fairly complicated heat treating requirements. This includes cryogenic treatment. You can have A-2 with the same hardness and very different properties.