O1 got an unfair bad rap.

[Malcolm Schweizer]

I recently posted looking for some O1 steel chisels. I found a set made by Andrew Kimmons at Kimmons Hand Tools. They arrived today and they are wonderful. I want to first say buy from him with confidence. I love these and the handles are perfect- long enough for paring, yet fat enough for striking.

My post, however, is in defense of the O1 steel. It got a bad rap due to it “needing more frequent sharpening.” I, myself, many years ago, went with the A2 Lie-Nielsen chisels because I didn’t want to spend a lot of time sharpening. Now that I am older, wiser, and more experienced, give me O1 chisels any day. The steel takes a sharper edge than A2 or PMV11. It literally gets sharper. It is to me very noticeable, but I do a lot of paring, so maybe I am sensitive to minute differences. It does NOT require constant sharpening- just a few more touch-ups here or there. Also, it is easier to sharpen. That is a big plus to me. I love sharpening things, but I also prefer to get back to work. I keep a fine stone on my bench when working to quickly swipe a chisel over. I would rather have easier to sharpen and takes a better edge over harder to sharpen but have to sharpen less frequently.

To be fair, A2 isn’t much more difficult to sharpen. PMV11 I literally groan when I have to sharpen. O1, however, is quick and takes a fine edge.

453583

[Tom M King]

01 for me, and the woods I work too!!

[Jim Koepke]

Another vote for O1, almost all of my chisels are O1. A few of my plane blades are A1 or A2. There are also a few PMv-11 blades in the shop. The PM seems less trouble for me to sharpen than the A1 & 2.

jtk

[Rick Dettinger]

I have some O1 carving tools from North Bay Forge in Western Washington State. They are hand forged and take a very good edge. I strop often, using Al Oxide on leather. Don't need to visit the stones very often.
The O1 carving tools from Pinewood Forge are very nice also. They sell the blades, if you want to make the handles. I did.

Best,
Rick

[scott lipscomb]

+1 here. I have made a few blades, too, from internet purchased O1. Super easy to make anything that I need. I also especially like that I can get a really good edge with just the Washita and green compounded strop.

[Malcolm Schweizer]

+1 here. I have made a few blades, too, from internet purchased O1. Super easy to make anything that I need. I also especially like that I can get a really good edge with just the Washita and green compounded strop.

I really need to do this, but I never have time.

[Mike Brady]

Lie-Nielsen reportedly had problems with inconsistency in their O-1 steel, however that might have been from the manufacturing perspective. Certainly their customers would still buy O-1 if they offered it. I have some chisels and plane blades from them in the 0-1 alloy, and I find that a keen edge is easier to achieve than with the A-2 versions of the same tools, so I will use the A-2 for coarser work and the O-1 for finish work or paring. By doing that I can go longer between sharpening sessions and perhaps get better results. To me the real advantage of O-1 is the variety of sharpening media that can be used, whereas the A-2 pretty much requires waterstones for best results.

[Ron Brese]

If one buys the cheapest 0-1 tool steel they can source then you will end up with an inferior product. Carbon content can vary widely. Some of the cheaper stuff can have carbon content as low as .72%, whereas a good domestic 0-1 tool steel can have carbon content of 1% or more. As you can imagine there would potentially be quite a bit of difference in the tools made from those steels.

Then of course there are issues with proper heat treating. Hardening is pretty much the same with most oil hardening tools steels even though it pays to read the manufacturer's specs. Some do vary but the most difference is in the tempering specs. Also the tempering properties could be different based on the end use.

For instance you might want to leave a plane iron slightly harder than say a chisel that would be used or chopping.

I've heard recommendations for tempering to 400 degrees for an hour. If you're making a chopping chisel using that tempering spec will most likely leave you with a chippy chisel. If tempered properly one should be able to pare with a chisel, then chop with it and then be able to go back and pare with it. Most likely if it's tempered at 400 degrees for one 60 minute tempering cycle then I doubt it will pare well after it's used or chopping.

Presco 0-1 from the Marshall mill in PA. recommends it be tempered at 450 degrees to achieve a hardness of RC 58 which would probably be a more reasonable hardness for a chisel. A chisel blade that is of high quality steel and is normalized twice before hardening and then goes thru 2 tempering cycles stands a chance of being a good tool. Otherwise you may end up with a tool that gets a bad rap.

Ron

[Larry Frank]

Not all O-1 is Equal.

This is one of the best comments that I have read. It is important to understand that all tool steels are made to a range of chemistry. These variations can lead to some large differences in properties. This is also true of the processing of the steels.

It is very easy to have two lots of O-1 perform very differently in terms of edge sharpness or chipping. The same goes for A-2 or other tool steels.

[Warren Mickley]

I've heard recommendations for tempering to 400 degrees for an hour. If you're making a chopping chisel using that tempering spec will most likely leave you with a chippy chisel. If tempered properly one should be able to pare with a chisel, then chop with it and then be able to go back and pare with it. Most likely if it's tempered at 400 degrees for one 60 minute tempering cycle then I doubt it will pare well after it's used or chopping.


I have some chisels that were tempered at 375. They do not chip when chopping. I do prefer chisels that are more highly tempered because they are easier to sharpen.

[Scott Winners]

I like O1 because it is easy to sharpen. I like A2 (at high bevel angles) because I don't have to sharpen as often. I have my first PMV11 iron on back order at Lee Valley.

If I like PMV11 half as much as some of you do I will get a spokeshave blade in PMV11. Usually when I sit down at my shave horse with my spokeshave I bring the sharpening gear over so I can resharpen (my O1 spokeshave iron) without having to get off the horse.

I don't have nearly the experience of many users here, but the often expressed opinion that O1 can take a finer edge than A2 seems to be true in my shop. I am basing my judgement on the feel of the wood off the tool, not taking the edge to an electron microscope.

I _think_ I read a Tom L-N interview a few years ago that was already a few years old then where Tom said the contractor who was doing the tempering on the L-N O1 product retired and they just haven't been able to replace the operator doing the tempering. I think I read it on the internet so it must be true. I love my L-N tools, but A2 is not my favorite steel.

At the end of the day, ease of sharpening and edge retention are important to all of us. The "Holy Grail" if you will is a steel that is easy to sharpen and holds its edge forever. Until then, we discuss.

For now, on my bench planes I like O1. If PMV11 lives up to its hype, I will get a spokeshave iron in PMV11. If I need a tongue and groove plane someday I will likely order from Tom and deal with A2.

[Derek Cohen]

Scott, PM-V11 really does live up to its "hype". As fine an edge as good high carbon steel, and twice as enduring.

Regards from Perth

Derek

[Jerome Andrieux]

My post, however, is in defense of the O1 steel. It got a bad rap due to it “needing more frequent sharpening.”


O1 does simply not have a bad rap, no need to defend it.

[Phil Gaudio]

If one buys the cheapest 0-1 tool steel they can source then you will end up with an inferior product. Carbon content can vary widely. Some of the cheaper stuff can have carbon content as low as .72%, whereas a good domestic 0-1 tool steel can have carbon content of 1% or more. As you can imagine there would potentially be quite a bit of difference in the tools made from those steels.

Then of course there are issues with proper heat treating. Hardening is pretty much the same with most oil hardening tools steels even though it pays to read the manufacturer's specs. Some do vary but the most difference is in the tempering specs. Also the tempering properties could be different based on the end use.

For instance you might want to leave a plane iron slightly harder than say a chisel that would be used or chopping.

I've heard recommendations for tempering to 400 degrees for an hour. If you're making a chopping chisel using that tempering spec will most likely leave you with a chippy chisel. If tempered properly one should be able to pare with a chisel, then chop with it and then be able to go back and pare with it. Most likely if it's tempered at 400 degrees for one 60 minute tempering cycle then I doubt it will pare well after it's used or chopping.

Presco 0-1 from the Marshall mill in PA. recommends it be tempered at 450 degrees to achieve a hardness of RC 58 which would probably be a more reasonable hardness for a chisel. A chisel blade that is of high quality steel and is normalized twice before hardening and then goes thru 2 tempering cycles stands a chance of being a good tool. Otherwise you may end up with a tool that gets a bad rap.

Ron

Ron: Thanks for that enlightening writeup! Phil

[ken hatch]

O1 does simply not have a bad rap, no need to defend it.

Ain't that the truth,

ken

[Warren Mickley]

Stainless steel has a bad rap. Maybe that is why Lee Valley did not publish the information that PMvii is stainless. I stopped using stainless in 1965.

[Derek Cohen]

Warren, you're now talking out of the wrong hole. You have read the extensive testing David did and posted at Wood Central. For someone who admitted that he went into testing PM-V11 with a great deal of skepticism, he came out a total believer. David would now argue that it is the best tool steel available for woodworkers.

I use PM-V11 all the time. I use O1, W1, A2 and M4 as well, amongst others. I did blind testing for Lee Valley many years ago. I have completed testing with chisels of different steels, and posted the results on my website. So ... please, play your games elsewhere.

Regards from Perth

Derek

[David Bassett]

... I _think_ I read a Tom L-N interview a few years ago that was already a few years old then where Tom said the contractor who was doing the tempering on the L-N O1 product retired and they just haven't been able to replace the operator doing the tempering. I think I read it on the internet so it must be true. I love my L-N tools, but A2 is not my favorite steel. ...

Well, I don't remember reading that, but I did hear Thomas Lie-Nielsen say that publicly. :) It was at PopWood's (RIP) Wood Working in America 2016 during a panel discussion.

I'm not sure how L-N was on the panel of small (or boutique?) plane makers, yeah they're smaller than LV, but compared to the other guys on the panel L-N seemed like GM versus Joe who completes a car in his garage once every couple decades. Anyway, the panel was ask what steel they used and why. Each answered "O1 because I can heat treat it myself", until it got to Tom. He replied "A2 because our O1 heat treat vendor retired and the only alternative we found locally with the quality we want does A2." (Quotes probably paraphrased some.)

[Curt Putnam]

O1 does simply not have a bad rap, no need to defend it.

I've only been reading woodworking forums for about 118-20 years. During that time I do not remember anybody dissing O1. Lots of articles about this or that alloy having longer edge life but nine saying that they got sharper than O1. Thus far, my PM-V11 edges get as sharp and last longer at angles of 25° or better. I've not tried it lower angles. I took the PM-V11 iron that came with my shooting plane and put it in my LA Jack and the O1 iron in the shooting plane. I do not run the shooter enough for edge life to be an issue.

[Charles Guest]

There are apparently a lot of people in this thread unfamiliar with the concept of "damning by faint praise."

[John C Cox]

O1 is good stuff, but it's pretty new on the grand scheme of things.

The better chisels of old were simply clean, fine grained, plain high carbon steel. The big thing was always heat treating them properly to get the benefit of the carbon and clean steel.

One of the eye openers for me, when I started down the rabbit hole of steel alloys was how easy it was to have lots of carbon in steel, but not much of it was useful because of improper heat treatment.

The steel guys know this, but the business guys push for faster cycle times, yielding higher throughput levels... The trade off ends up leaving carbon out of solution or incomplete conversion of Austenite to Martensite - because that stuff takes time.

And then there's warpage and cracking... Water quenching is a beast for warpage and cracking. Olde Chisels were heat treated as square sided firmers, then all the bevels were ground post heat treatment. That's slow and expensive. They turn into bananas if you machine bevels first, then heat treat second...

And so the answer to all this was magic alloys, that were better on paper, more cooperative with their high volume industrial production...

Luckily, the market has shifted to the point where we can now get good stuff made by boutique makers... It's spendy, but that's about the only way to get it now.