LN block - O1 or A2

[AUswimKC]

I have a LN low angle block plane I got second hand. How do I know if the blade is O1 or A2?

This particular blade has no markings. Not even Lie Nielsen. Any help appreciated

[JimReed@Tallahassee]

Metal is not as easy to identify as wood. That's why we are woodworkers and not metalworkers.

A2 has 5% chromium where O-1 has none, but I don't know how you can easily differentiate between them except through spark testing. Take a known piece of O-1 and spark it with a grinder. Then do the same to your unknown blade. Spark patterns should be the same. Pay attention to the pattern, color, and density of sparks.

Of course, I have found that O-1 sparks vary depending upon the batch. Some spark orange and some spark yellow. Most O-1 sparks are white - yellow in my experience.

If you have some acid, you could try an acid test. Seems to be that the chromium in A2 would react less to acid. But real acid testing can be dangerous. Maybe mild vinegar would be safer (but slower).

And then there is use. The A2 is tougher but has larger pieces of carbide. Hock recommends a larger bevel to prevent edge crumbles. If your blade has a 25 degree bevel and it crumbles, then it is probably A2.

Hope this helps. Good luck with your new plane.

[DaveBeauchesne]

Others will chime in I am sure, but the older ' No Markings ' blades were the O1 type IIRC.

[Admiral]

DaveBeauchesne said:

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Others will chime in I am sure, but the older ' No Markings ' blades were the O1 type IIRC.

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+1

I like O1.

[RB61]

Admiral said:

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[blockquote]DaveBeauchesne said:

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Others will chime in I am sure, but the older ' No Markings ' blades were the O1 type IIRC.

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+1

I like O1.

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[/blockquote]

+1

[Ricky]

Mine is one of the older ones with no marking.

[Mike Brady]

The older ones without the Lie-Nielsen markings were not A-2, but they were not 0-1 either. Someone chime in if you know. Maybe D-2? I have an early LAB plane that has the plain iron in it. I like it.

[Derek Cohen]

Mike Brady said:

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The older ones without the Lie-Nielsen markings were not A-2, but they were not 0-1 either. Someone chime in if you know. Maybe D-2? I have an early LAB plane that has the plain iron in it. I like it.

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The early LN blades were W1 (water hardening). These are often viewed as the best of the O1 types.

Keep in mind that A2 is more durable, and in a low angle/BU plane, the low bed reduces the impact vector on the bevel edge, and these blades have, for this reason, improved longevity. I have demonstrated better performance from an A2 blade with a 25 degree bevel on a 12 degree bed than an A2 blade with a 30 degree bevel on a 45 degree bed.

In other words, low angle planes work very well with A2 - be content if your LN or LV or other LA plane uses it. O1 will sharpen up faster, but sharpness, per se, is a factor that relies on media used and the skill to use it.

Regards from Perth

Derek

[Blaine]

Call LN and ask them. They support all their products regardless if they've been resold.

Frankly, I don't think it matters which steel it is. You're going to have to sharpen it regardless.

Blaine

[Bruce Haugen]

One way toward an educated guess is to sharpen it on waterstones. O1 sharpens easily and A-2 not so much. With my King stones, I could hardly make any progress at all on my shoulder plane and block plane A-2 blades. Diamond paste on a cast iron block made quick work of both of them.