Problems sharpening/using PM-V11 blades

[Jim Koepke]

Location fixed

Interesting, I retired from BART. Would occasionally get out to Dublin. Used to visit a Woodcraft store there at times.

jtk

[Kees Heiden]

It is probably not the same as CPM-V11. It doesn't have that much vanadium. I don't think it has much vanadium at all. Vanadium carbide is very hard and difficult to sharpen, even grinding takes ages. PMV-11 isn't like that at all. It is about twice as much work as O1. It is definitely a stainless steel though. So, more a steel like 440C or D2. But it is tempered to a higher HRc value then these usually are.

When you search around for powder metal steels you will find that most contain a significant amount of vanadium, because vanadium steel is very wear resistant and in the industry they use it for pressing dies, for example in the automobile industry. The difficulty of sharpening isn't that important for them.

So when you sum up the properties of PMV-11, it isn't too difficult to find good candidates.
- Stainless steel, so it contains a lot of chrome
- Relatively easy to sharpen, so not a huge amount of vanadium (rules out a lot of readilly available steels)
- Powder metal
- Can be hardened to high HRc values, 61 to 63 according to LV. That's more then standard 440C or D2.
- A guess from me: it is most probably a standard knife steel, made in America, because they are so secretive about it. Not something special from Japan, more difficult to get.

A good candidate that ticks all the above boxes is Carpenter CTS-XHP. Essentially an improved, PM version of 440C. http://cartech.ides.com/datasheet.aspx?I=101&E=343

BTW, the powder metalurgy steels have a fine grain compared to similar high aloy steels made in the traditional manner. But high carbon steel still trumps them all in this respect.

[Patrick Chase]

That Woodcraft went belly-up just before I moved here (which is probably a good thing for me - less temptation to binge-purchase so-so tools). The only one in the BA is in San Rafael now.

[Patrick Chase]

Yes, now that I think about it you're almost certainly right. While I don't have direct experience with high-Vanadium PM steels, I know that Derek was unable to put a fine edge on CPM-V10 using Shapton Pros for one of his metal comparisons, and that puts it in a completely different league than PM-V11. Thanks for the correction!

On a related note, IMO the fact that Veritas/LV haven't patented or done a defensive publication for PM-V11 is a dead giveaway that it's either somebody else's steel or in the public domain.

The notion that they have IP around the composition (as opposed to the process) and are holding it as a trade secret is patently absurd (pun intended). I used to sit on IP review committees for a former employer, tasked with deciding whether to patent, publish, or trade-secret-ize invention disclosures. The cardinal rule of trade secrets is that you must be confident that you can actually keep them a secret. There are a few reasons why this is so:

1. Trade secrets are only protected from theft, not from independent analysis. If a competitor bribes my employee to steal my secret then I can pursue legal remedies against both. If my competitor or some other party legally acquires my product and reverse-engineers my "trade secret" then I have no protection or recourse (unless the analytic approach they used is specifically prohibited, for example by the infamous DRM provision in the DMCA). The proverbial cat is out of the bag at that point.

2. If I keep something a secret and somebody else subsequently invents the same thing independently (not via reverse-engineering), then they can usually patent it and prevent me from using it even though I developed it first. Prior art must be public to forestall subsequent patents, and that's precisely why it's very common to defensively publish inventions that you choose not to patent but that you don't think can be kept secret. There are entire journals dedicated to such publications (which exist for additional reasons that I won't go into here, except to note that sometimes you want a publication that you can subsequently point to when advantageous but that nobody is likely to find on their own. My current employer made that a whole lot harder to achieve, though, and IMO that's a good thing).

3. If I keep something secret and somebody else reverse-engineers it and publishes their analysis, then that publication is *their* intellectual property (via copyright) and I have no control over it whatsoever. Again this is a reason to preemptively publish.

Steel composition can be trivially determined via common analytic methods, so I think it's safe to conclude from the lack of publication/patent that Veritas/LV either hold no IP around the composition, or are the victims of extremely poor legal advice.

Disclosures: I'm an engineer, not a lawyer, though as noted above I have experience in this area. Also, I've simplified in a couple respects to keep things readable.

It is probably not the same as CPM-V11. It doesn't have that much vanadium. I don't think it has much vanadium at all. Vanadium carbide is very hard and difficult to sharpen, even grinding takes ages. PMV-11 isn't like that at all. It is about twice as much work as O1. It is definitely a stainless steel though. So, more a steel like 440C or D2. But it is tempered to a higher HRc value then these usually are.

[Kees Heiden]

Completely agree. It is like making the weight of your new doodad a trade secret. Everybody with access to a scale can break your secret, after which it stops to be a secret. Really, this situation isn't any different.

[Mike Henderson]

Good discussion - thanks. I'm pretty sure that LV sources that metal (the PM-V11) from a North American source. I had a conversation with Rob Lee where he commented that he wanted his tools to be made in NA with material from NA. I think they specifically indicate if a tool came from other than NA.

I really doubt if they have any IP in that metal.

Mike

[Kees Heiden]

Last spring, over on woodcentral a guy named Bill Tindal posted that he put one of his PMV chisels in such a mass spectro machine. There was quite an uproar if he should publish the result or not.

[bill tindall]

It is not CPM 11V

[bill tindall]

Not mass spec. Analysis is done by nondestructive X-ray fluorescence. Can be done in 30 seconds on any flat surface.

[Andrew Pitonyak]

I've read enough old threads to know that this has been hashed over ad-nauseum and I'm not contributing anything new, but:

Yeah, I can finish that with.... "but... then Andy learned something because Patrick posted".

There is a reason that you see article types repeated in magazines over the years. Even if some of the old-timers know the stuff, new people do not know it and some of us forget some of it. For example, I had no idea which of Stu's stones was best for PM-V11. I keep thinking that I should add to my water stone collection and try them, but what I have works and buying more is just so addicting!

Keep posting Patrick!

[Patrick Chase]

Not mass spec. Analysis is done by nondestructive X-ray fluorescence. Can be done in 30 seconds on any flat surface.

Depends what you want to know, right? IIRC XRF can't do Carbon.

[bill tindall]

The question was how to identify what alloy it was and that quest did not involve mass spectrometry, nor is it likely any chemist would pursue that route. I didn't need carbon to identify the material (in this case), nor did I need to sacrifice any tool.

[Pat Barry]

The question was how to identify what alloy it was and that quest did not involve mass spectrometry, nor is it likely any chemist would pursue that route. I didn't need carbon to identify the material (in this case), nor did I need to sacrifice any tool.

Well, what did you learn? Even if it is a trade secret, the fact that virtually anyone who needs the information can easily get the answer through simple techniques such as XRF means that it really isn't secret at all.

[Patrick Chase]

Well, what did you learn? Even if it is a trade secret, the fact that virtually anyone who needs the information can easily get the answer through simple techniques such as XRF means that it really isn't secret at all.

Having looked through the thread on the other forum, I have a few thoughts:

1. There are some people in our community who appear to have no idea why intellectual property works the way it does. The system is intentionally biased to promote disclosure, whether by patent or publication, because we don't want to return to the old progress-inhibiting system of medieval guilds. One dark age was enough, thanks. I'm not arguing that our current system is remotely ideal (IMO SW patents are a disaster), just that there's a sound reason for biasing toward disclosure in any such system.

2. As noted above the analysis is Bill's IP (via copyright) to do with as he chooses.

3. Given the amount of (IMO unwarranted) anti-disclosure vitriol in that thread I'd probably keep my head down, too.

If you want to know then take your blade to any of the very large number of services that provide XRF.

[Pat Barry]

Having looked through the thread on the other forum, I have a few thoughts:

1. There are some people in our community who appear to have no idea why intellectual property works the way it does. The system is intentionally biased to promote disclosure, whether by patent or publication, because we don't want to return to the old progress-inhibiting system of medieval guilds. One dark age was enough, thanks. I'm not arguing that our current system is remotely ideal (IMO SW patents are a disaster), just that there's a sound reason for biasing toward disclosure in any such system.

2. As noted above the analysis is Bill's IP (via copyright) to do with as he chooses.

3. Given the amount of (IMO unwarranted) anti-disclosure vitriol in that thread I'd probably keep my head down, too.

If you want to know then take your blade to any of the very large number of services that provide XRF.

Harrumph!!