A tale of 2 blades and a Veritas custom #5

[John C Cox]

With the back order that might still be an option. I was curious how they would stack up against each other in the same tool. The few PMV blades I have are in tools I don’t have O1 in.

It really all depends on the type of work you are doing and the wood you are working.

If you are doing a lot of work on soft wood - spruce, pine, doug fir, cedar.. A super keen Sharp edge matters most. Carbon steel has the edge because it easily takes a keen edge and cleans up quick.

Medium density hard woods - cherry, mahogany, soft maple, ash, walnut, etc - a super keen edge doesn't matter as much. Super alloy will last nearly forever. Carbon steel will do fine, though. Pick whatever makes you happy.

High density abrasive hardwoods - Rosewood, bubinga, mesquite, hard white oak, and almost everything from Australia. You pretty much have to use fancy super alloys if you really want to get much work done... These eat Carbon steel...

Pick your poison....

90% of my plane use falls into the 1st two categories. I really like my CS irons best for this duty - but I do have a set of HSS irons for use on horrible wood...

[Patrick Chase]

I belong to the group that uses and says A2 is no where worse than O1 in sharpness. In fact, for ordinary users, sharpening skills matter more than the difference in two steels when it comes to sharpness. I dont care about their difference under the microscope; the work speaks for itself and I am happy with the results after dropping all my O1 blades.

The comparison between A2 and O1 is more subtle than a lot of people on both sides of the argument make it out to be.

Let's start with provable physical reality: A2 has much higher alloyant content, particularly Chromium. This has a couple consequences: The grain structure is larger (see the comparions in Hock's book and website for example), and the dominant carbide is Chromium carbide instead of cementite (Iron carbide). It is also true that not all A2 is created equal. By austempering at a higher-than-usual temperature you can reduce the grain size a bit though not to O1 levels. Doing so causes high retained austenite (incomplete hardening) when quenched to room temperature, but that can be corrected by cryo treatment. LN is certainly playing this game, and I suspect that LV and Hock are as well. Any maker with access to professional HT capabilities would be crazy not to.

What all of this means for practical edge taking depends on a number of factors, which is probably why there are such a wide range of opinions.

First of all the user has to be sharpening to a very high standard, and has to care about very small differences. The sorts of differences we're talking about here are potentially relevant to final smoothing due to potential for tracking, but irrelevant for roughing and probably jointing. If you sand your work after planing then stop reading, because you're going to obliterate the evidence anyway.

Initial sharpness depends heavily on honing medium. The Iron carbides in O1 is softer than all common honing media including Silicate, so basically any stone should be able to bring O1 to an ideal edge. The Chromium carbides in A2 is harder than Silicate (most natural stones) but softer than Alumina (most synthetics). This means that a natural stone will merely "erode" the ferrite matrix around the carbides until they fall out, leading to a noticeably ragged edge. This explains Warren and Brian's experiences. A2 and Arks don't get along, 'mkay?

The more interesting discussion is around how the edges "develop" with use. When you use a steel that contains carbides (as both O1 and A2 do) the ferrite wears faster than the carbides. As the carbides become exposed they take more of the cutting forces and slow the wear of the surrounding matrix. A2's wear resistance comes from having a lot of very hard carbides that act in this manner. You wouldn't be far off the mark to think of very small carbide circular saw teeth. The grain size of the steel determines how "prominent" those teeth are and how rough the edge is. Continuing the circular saw analogy, the difference between A2 and O1 is like a 40-tooth combo blade vs a 96 tooth crosscut (where non-PM D2/HSS/stainless are 24-tooth rip blades). In my experience there is a real difference in edge smoothness between O1 and A2 when both have been used a fair bit.

PM steels "cheat" by achieving both fine grain structure and a high percentage of hard carbides.

[Tony Wilkins]

To answer a couple of things...

I sharpen on Suehiro dual stones or king water stones.

I work mostly oin poplar, cherry and walnut though I have a couple of future projects I want to do in oak.

[Pat Barry]

Patrick, out of curiosity, since you elaborated quite a lot on grain sizes, what are the nominal carbide grain sizes for A2, O1, PMV11?

[Patrick Chase]

Patrick, out of curiosity, since you elaborated quite a lot on grain sizes, what are the nominal carbide grain sizes for A2, O1, PMV11?

There aren't really "nominals" since it depends on details of processing. The best online resource I know of for A2 vs O1 is Hock's blog post here: https://hocktools.wordpress.com/2010...one-more-time/. I have some books (including Hock's) that have better comparisons.

To be honest I've never seen a micrograph of CTS-XHP, though I've seen plenty of broadly similar PM steels in the past (and linked one in a reply to Stanley a while back). The carbides are basically invisible, as with O1.

This reference describes the austenitization/cryo trick for A2 that I outlined on pp 79-80: http://allaboutmetallurgy.com/wp/wp-...ool-Steels.pdf

EDIT: The fact that CTS-XHP hones well on Arks (which I've confirmed) is a very strong indicator of a fine structure. It has much higher Cr content than A2, of which a significant percentage is in carbides rather than solution. If those weren't *very* small then it wouldn't fare well on such a soft medium.

[Pat Barry]

There aren't really "nominals" since it depends on details of processing. The best online resource I know of for A2 vs O1 is Hock's blog post here: https://hocktools.wordpress.com/2010...one-more-time/. I have some books (including Hock's) that have better comparisons.

To be honest I've never seen a micrograph of CTS-XHP, though I've seen plenty of broadly similar PM steels in the past (and linked one in a reply to Stanley a while back). The carbides are basically invisible, as with O1.

This reference describes the austenitization/cryo trick for A2 that I outlined on pp 79-80: http://allaboutmetallurgy.com/wp/wp-...ool-Steels.pdf

EDIT: The fact that CTS-XHP hones well on Arks (which I've confirmed) is a very strong indicator of a fine structure. It has much higher Cr content than A2, of which a significant percentage is in carbides rather than solution. If those weren't *very* small then it wouldn't fare well on such a soft medium.

Basically invisible? Hard to believe this is not well known with as much verbiage has been devoted to the benefit of O1 over A2 for producing fine edges vs carbide content

[Tony Wilkins]

Now that there’s a delay and apparently I just missed another free shipping I’m reconsidering whether I need the plane or not. I’ve been doing ok with the LN 62 so far.

[Sanford Imhoff]

FYI, if it matters to you, Lee Valley free shipping is back on starting today and going through the 21st.

[Tony Wilkins]

FYI, if it matters to you, Lee Valley free shipping is back on starting today and going through the 21st.

Yeah, but I ordered it a couple of days ago.

[Simon MacGowen]

Yeah, but I ordered it a couple of days ago.

Don't hold me to it but if you call customer service, I bet that they will waive your previous shipping fee since the order was placed so close to the current free shipping event. My understanding is that such requests have been accpeted before.

Simon

[Patrick Chase]

Correcting a typo since it's too late to edit...

It is also true that not all A2 is created equal. By austempering at a higher-than-usual temperature you can reduce the grain size a bit though not to O1 levels.

That should have said "austenitizing at higher-than-usual temperature", not "austempering". Austenitization is traditional heat treatment as we've all heard described many times, and is what is almost always done with A2. Austempering is a one-shot harden-and-temper process using an interrupted quench in a molten salt bath, that is used with some other alloys to achieve very high toughness at moderate hardness (up to ~Rc59). Narex is probably the most notable maker that uses austempering. I've never heard of it being done with A2, and from a glance at the I-T curves I suspect that it may be impractical due to the long conversion times required to obtain lower Bainite.

[Tony Wilkins]

Don't hold me to it but if you call customer service, I bet that they will waive your previous shipping fee since the order was placed so close to the current free shipping event. My understanding is that such requests have been accpeted before.

Simon

emailed them and they refunded it without blinking an eye.

[Matt Lau]

I think that I agree with the other guys in saying--what wood are we talking about?

FWIW, I have only PMV11 blades in all my LV planes. Once I have things honed and dialed in, I just want to get to work.
They stay sharp a really long time, take a ton of abuse, and sharpen easily on ceramic stones (I use spyderco, but lust after Japanese ones).

For chisels and knives, I like plain carbon steel.
It's easy to touch up an edge really quickly.

For planes, I like this PMV11 stuff...otherwise it's unscrew, unscrew, unscrew. Take out blade. Hone. Clean. Oil. Place back in action. Screw, screw, screw. Retighten and adjust. Cut....repeat.


Have you thought of getting the custom Jack with a fine blade, and later making/refurbing a #5? Rough work doesn't need a precision machined Veritas custom plane. Also, you won't cry if you drop it.

[Simon MacGowen]

emailed them and they refunded it without blinking an eye.

Good to hear that!

The typical LVT customer service behavior...don't know if it is a good thing to us consumers in the long run as nothing seems to be holding us from buying from them!

Since you received your refund without any delay, it means the customer service people have been truly empowered. Last time I dealt with a customer service (unrelated to woodworking), I had to be referred to a "Loyalty Supervisor" before I got what I wanted. Why wasting both parties' time when the outcome would be the same? Empower the front-line foot soldiers and save money (from quicker decision making)!

Simon