Reprofiling CPM Cru-Wear

[RLDubbya]

You might consider picking up a WorkSharp Ken Onion with the Blade Grinding Attachment. Essentially this gives you a "hobbyist" level belt grinder, and makes reprofiling work a breeze.

It also makes it easy to compromise the excellent heat treatment at the edge. I didn't spend good money on Spydies to not take advantage of their HT skills. Preserve the steel!

Edit
P.S. nice work, Evil!

I'm not sure what justification you have for this statement, but I would like to read it and discuss. If you mean that by abusing your tools you can ruin what you are working on with those tools - well, sure, that's true. It's also uninteresting, because I think its safe to assume that we are all mature enough to learn how to use our tools. Please take my comments constructively, and offer solid arguments / positions that we can debate and all learn from - thanks!

[Nate]

Fwiw RLDubbya, I believe Mattman was referring to the risk of damaging the heat treatment by overheating the edge during power grinding, effectively blowing the temper. Usually any "bad steel" is only a few microns deep and can be removed in subsequent manual sharpening, but if you don't know what you're doing I think there is a risk of doing more significant damage.

I actually have a 1x30" from Harbor Freight and have done a fair amount of re-grinding and re-profiling with it. Actually rigged up a drip system as well to run the belts wet and prevent any heat build up, but I still asked David for help with the Manix because it's not easily replaced if I had screwed up, either on the grind or by overheating the edge. I'm actually more comfortable using it to regrind the primary than doing edge bevels, but it is pretty handy to have and I keep getting more comfortable with it as I get more experience.

[Evil D]

I will say if you've ever used a belt to put a bevel on a knife then you know how difficult it can be to get a clean even bevel, so it's easy to understand how an edge like this happens. It's debatable whether or not it should have slipped through CQ that way.

[RLDubbya]

Fwiw RLDubbya, I believe Mattman was referring to the risk of damaging the heat treatment by overheating the edge during power grinding, effectively blowing the temper.

Well, if you notice: I specifically mentioned "reprofiling" using power. The reason for my use of words (they do mean something, after all) in this case: we reprofile an edge using power; let's assume that causes some damage (an assumption not yet proven). We then sharpen manually - and thereby we remove the issue of power grinding damage via power sharpening, b/c we are not power sharpening.

I'll now further note a couple things: one, just about every manufacturer, and I'm fairly certain Spydie, does in fact power-sharpen their blades in the interest of expediency. So it's being asserted that Spyderco, who has invested a lot of money and time into understanding and performing heat tempering, is now purposefully destroying that tempering? OK - not sure I agree, but at least I know what is being asserted.

Another thing I'll note: Roman Landes did the research on this stuff, and came to the conclusion that even non-power dry sharpening destroys the steel edge. He concluded, IIRC, that we must use water stones or another lubed sharpening method to avoid steel damage.

I don't believe that David - the Evil D - used water stones or any other lubed sharpening method; I'll also note that the preferred sharpening technique for most folks on this forum involves the Sharpmaker, used dry. Thus, no matter how you slice it, you are either advocating a sharpening method which causes damage or you are disagreeing with Roman's research.

FWIW: I've also been told by a metallurgist that using a diamond based stone will effectively destroy the molecular structure of modern super-steels, like CPM S30V, S35V, S90V, S110V, MaxaMet, ZDP-189, etc. and render them unable to hold an edge properly. I'm just tossing that out there as a random "factoid" to demonstrate that there are a lot of weird claims which require more research.

[Nate]

Well...

I'm not exactly sure what position you're advocating, but here's my take on the topic in general:

-Power sharpening can cause h/t damage and can lead to heavy burr formation, fact. It is also simply much easier to mess up because material is removed at a much faster rate. Please note though that I am not claiming that power sharpening always causes damage or that wet grinding eliminates the risk of damage, or even that you can't damage steel or create a heavy burr while hand sharpening. User skill, jigs, and belt/stone selection & condition are all important modifying factors.

-Yes, nearly all manufacturers power sharpen. No, they are not purposefully "destoying" anything. The general discussion, I believe, is more about what is optimal vs. what is practical. I haven't had any actual complaints about the factory edges on my Spydies or ever sent anything back for warranty evaluation, I try to keep my expectations reasonable. However, how many user reports have you seen about edge retention increasing after elu's sharpen themselves a few times? It seems very common to me. My impression is that there is a lot of evidence pointing to this being true.

-On Landes, I found a quote from Cliff where he states, "Roman [Landes] has never made the claim that anyone sharpening a knife without coolant is producing over heated edges," so I am not sure about your assertion. Please note though that I cannot claim any direct knowledge as I have not read Landes' work. AFAIK, it still hasn't been translated from German and frankly it's probably more detailed and technical than I really want/need to know. He may have discussed it in english somewhere, but again I don't know. Here is the source thread for the quote though. You may enjoy the read, if you haven't already: Source

-I'm mostly interested in minimizing the risks rather than acheiving anything optimal and I also recognize the limits of my skill. I think the Work Sharp is a nice tool, my brother in law has one and raves about it. Given the option though, I prefer to use my 1x30" with the wet/dripline set up. One of the primary benefits I've seen from this isn't even related to heat build-up or damage. Wet grinding virtually eliminates dust/slag in the air and sparks. I would probably continue to do it this way even if that were the only benefit. 

However, going back to the current limits of my skill, with a blade that is highly valuable to me like the Cruwear Manix, I believe having someone like Evil D do a BEAUTIFUL job by hand with his Edge Pro further reduced the risks and increased the quality of the end result over what I could achieve with my 1x30". The question of whether lubrication on the hand sharpening would have been more "optimal" is a little interesting in an academic sense, but immaterial to me in this case as I believe the outcome is superior to what I could have done on my own at this time under any circumstances.

Cheers,
Nate

[Evil D]

For the record, I do keep my stones soaked with Windex, mainly just to help keep them from clogging but I suppose it does also lubricate and reduce heat on some level.

[Nate]

Thanks for clarifying. I thought you had mentioned that before, but I didn't want to put words in your mouth and whether you did or not in reality wasn't central to what I was trying to say anyway.

[RLDubbya]

I'm not exactly sure what position you're advocating, but here's my take on the topic in general:
Cheers,
Nate

I am going to [try to] make clear what I am asserting, and no more. I think that, thanks largely to me, this thread has been hijacked from its original topic so far into an ocean of minutiae as to make dry land little more than a distant memory in the brains of readers. I think, if we wish to continue the discussion of power sharpening, heat treating, etc., we would be advised to start a new thread.

My position is simply that, if any person wishes to decrease the amount of time spent reprofiling a knife blade, (s)he should feel free to use power grinders to do so; by using such power grinders as are available today, now, the user can slash a significant amount of time from the task of reprofiling without risking the integrity of the finished blade.

Secondarily, I would like to assert that there is a surprisingly high degree of conflation between resharpening and reprofiling, and such conflation is being exploited to make resharpening appear more dangerous than it is in actuality.

Thank you for presenting your thoughts, and thank you for, generally, doing so with good, transparent, lucidity so that we may all learn from debate.

I am now off to reprofile a blade using a WorkSharp with no lubricant; after I finish reprofiling that blade, I will then resharpen that blade by hand, using my SharpMaker with medium, fine, and uf stones; I will follow up with a last step of stropping manually with a conventional leather strop and liberal use of green compound.

Warm regards,

RLDubbya

[Nate]

My position is simply that, if any person wishes to decrease the amount of time spent reprofiling a knife blade, (s)he should feel free to use power grinders to do so; by using such power grinders as are available today, now, the user can slash a significant amount of time from the task of reprofiling without risking the integrity of the finished blade.

Secondarily, I would like to assert that there is a surprisingly high degree of conflation between resharpening and reprofiling, and such conflation is being exploited to make resharpening appear more dangerous than it is in actuality.

Thank you for presenting your thoughts, and thank you for, generally, doing so with good, transparent, lucidity so that we may all learn from debate...

You're welcome, I like talking about knives :D

Thanks for explaining also, I can see how that point of view has merit. The time difference with power is certainly huge. I don't really sharpen off the belts either, mainly regrinds and a few reprofiles (getting better).