Caly Jr. ZDP 189, reground by Tom Krein

db said:
What are all the better ways to increase the performance of a factory knife that someone has just bought for themselves?
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Buying a KMG, Bader, Coote, or Dozier with a custom-made 20" contact wheel of course or getting a cheapo $70 wet grinder (that's a lot of money, but not for a wet grinder).
 
Got my knives back from Mr. Krein yesterday. I've done some light cutting, but nothing much yet, this is a busy weekend. They are indeed quite impressive. I'm especially liking the Cabelas Mini Griptillian in D2. Like Cliff said earlier, it should be very good for abrasive draw cutting. Tom also cleaned it up, and ground in a nice swedge on the top of the blade, it really looks and cuts much better than the original.
 
Cliff Stamp said:
While I understand the point, this was one (of the many) failings of Juranitch's viewpoint. Many makers today still continue this farce by adding relief edge grinds to knives which is the worst way to increase performance. If the edge is too thick/obtuse you have to adjust the primary grind as Krein does, not slack belt the edge (and then cry hail the convex grind) as many people advocate. -Cliff
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Cliff, what am I missing here? Isn't Juranitch's first step of laying the blade down and grinding in a relief, to some degree the same as thinning the blade? Not getting into what a knife maker should do, but to sharpen one, the majority don't have the luxury of the grinding that Tom Krein does.

And why is this the "worst way to increase performance"?

Thanks
 
sodak, did you do any thinning, relief-back beveling, blade grinding, or what ever term you want to use for it, on the knife before getting the Krein treatment? My real trouble is I have a knife that needs some of Kreins help and I justmay send more than one to be done but I'm having trouble deciding if there is enough reason to have this done by Krein or if I'm getting pretty much the same performance with the thinning I do myself.
 
I didn't thin this particular one out. I do thin out most of my knives when I get them from the factory/maker. I haven't yet done much cutting with my Krein modifieds, but here are some pictures that can help explain.

Here is a stock Caly Jr. ZDP (burgundy), a VG 10 that I've thinned (grey), and the one I sent to Tom Krein (black). You can see how far my thinning went, as opposed to his re-grinding.

http://i137.photobucket.com/albums/q203/sodak_photos/p1010010-1.jpg

My thinning, while helping, doesn't go up nearly as far. As the knife dulls and I keep re-sharpening the microbevel, I'll need to keep re-thinning. With the primary grind thinned out, that won't be necessary.

To put things in perspective, in order to sharpen, when I've thinned the edge out, I can re-sharpen the knife in under 3-5 minutes on a diamond hone, no problem. That's ANY knife, I don't care what steel is used. With the re-ground edges, I can completely re-set the entire edge (including, of course, resharpening) in 3-5 strokes on a blue dmt stone. No kidding.

You almost have to see it to believe it.

The performance difference is unreal.

Here are a couple of Caly 3's:

http://i137.photobucket.com/albums/q203/sodak_photos/p1010011-1.jpg

and a Cabelas Mini-Grip (in D2):

http://i137.photobucket.com/albums/q203/sodak_photos/p1010017-1.jpg

I feel the need for a disclaimer. The Caly Jr.'s and Caly 3's, in my opinion, are about the best folders out there. Period. They will surpass probably 99.999% of the public's expectations of what a pocketknife should do. They (IMHO) outcut almost all other production folders, and are a joy to use. It is for this reason that I'm modifying them, trying to see if I can squeeze even more performance out of them. Please don't mistake this post as a criticism, it is not. Pretty much nothing else made the cut.

You have these things done to your favorite folders, you will, in all likelihood, incur some damage while using them, until you learn to respect thin primary grinds. You will also come about as close to a Jedi light saber as you will ever be able to do in this life! Enjoy!
 
Sodak thanks. I’m not really concerned about ease of sharpening but I’d bet many others are. I’d love to hear more thoughts comparing usefulness, sharpness, and the utility of the Krein knives to ones you’ve thinned, once you have used them. How thin did you go with the Caly, both the one you did yourself and the Krein one?
 
I'll mike them out and let you know. Give me a couple of weeks, and I'll be able to give you more info.
 
hardheart said:
... they should be grinding thinner primaries to begin with.
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Yes.

hardheart said:
... anything over a micron isn't doing the cutting, it's just keeping the cutting edge in place and not flopping around like tinfoil.
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Exactly.

gunmike1 said:
I don't posess your zen like skills at holding my cuts straight like you yet...
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Time, patience, and the willingless to break a bunch of knives to find out what you can and can't do. That is why I sent you a bunch of mine so you don't need to be concerned about your own dollar.

cbwx34 said:
... laying the blade down and grinding in a relief, to some degree the same as thinning the blade?
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No.

Not getting into what a knife maker should do, but to sharpen one, the majority don't have the luxury of the grinding that Tom Krein does.
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It is often the case that you don't have access to optimal tools/techniques, you don't then advocate it as such though.

And why is this the "worst way to increase performance"?
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Because it gives the lowest level of edge durability and worst ease of sharpening for a given level of cutting ability.

-Cliff
 
Cliff Stamp said:
Time, patience, and the willingless to break a bunch of knives to find out what you can and can't do. That is why I sent you a bunch of mine so you don't need to be concerned about your own dollar.
-Cliff
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I do appreciate it, and have learned a lot and been addicted to the ultrathin grinds. I have discovered the chipping issue from hard twisting cuts and gotten a lot better at controlling my cuts to avoid that, but am still a little gun shy about trying more HD stuff (except with the tip of the Byrd, as noted) until after I do more testing and gain a more steady hand. I certainly don't want to break the knives (though the Byrd is almost definately getting snapped when I try it on some wood work), but when testing the limits of thin edges that is a definate possibility. Hopefully I can send the knives back to you in one piece, excepting a few chips. I am trying to compile my cardboard, and after that I can try some more utility oriented tasks with the knives and see what they can do. If my technique improves at all maybe I can keep the edges in one piece doing general utility tasks with these thin guys.

Mike
 
This really opens up some interesting possibilities. I wounder how well Spyderco's H1 would hold up ground that thin? I have a PE Atlantic Salt that might be an interesting test subject. Seems like I am going to have to buy a Cabela's D2 Mini-Grip now...
 
I reground a Salt to a fairly thin flat grind and it was very durable, more so than a Sebenza in a similar edge configuration. Details are in the reviews.

-Cliff
 
Cliff Stamp said:
Because it gives the lowest level of edge durability

-Cliff
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Huh? What does the edge durability have to do with your relief grind? The durability of the very edge should only be dependent on the edge angle (ignoring the steel or rather assuming a given steel/heattreat). And the stability of the blade behind the edge is a function only of thickness regardless of how the thickness is achieved, hollow, flat or convex. And your definition of a relief grind is very different from what I would call a relief grind. Slackbelting a beveltransition is NOT what I would call a relief grind. And the hailing of the convex edge should have very little to do with the blending of a bevel transition. You seem lately on a crusade against convex grinds, disregarding your own early advice that you have to look at the specific geometry. Of course as you can see in the picture, the convex grind will actually have a thinner thickness behind the edge and leave more material higher up, and of course you could carry the relief grind all the way to the edge and hence change the edge angle and therefore also the edge stability. It all depends on how exactly your final geometry looks like.

I agree though that a relief grind is a homemade fix of primary blade grind and as such always imperfect, but not everybody has the means (or the patience) to completely regrind the blade. But regardless of how imperfect the fix is it will still improve the performance, so I am not quite sure why you have issues with it?

 
HoB said:
Huh? What does the edge durability have to do with your relief grind?
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Your question is unanswerable since you misquoted the comment, the clause at the end of the statement was the critical factor.


You seem lately on a crusade against convex grinds...
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Most of my knives are convex ground, what I am trying to clearify are the actual properties of the grind.

I agree though that a relief grind is a homemade fix of primary blade grind and as such always imperfect, but not everybody has the means (or the patience) to completely regrind the blade. But regardless of how imperfect the fix is it will still improve the performance, so I am not quite sure why you have issues with it?
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Because it is advocated as optimal.

-Cliff
 
Cliff, my question is absolutely answerable and I did not misquote you either. Your mono-sylable posts that you have taken to lately, annoy me a little I must confess. When making such a statement, I think it would be worth your time to explain what you mean and under what condition it applies. What does "a given level of cutting ability mean"? . It seems nonsense to require the same cutting ablitiy of a blade that is ground from the spine down to one which had a relief grind applied one has more material left and is therefore obviously at a disadvantage. Also you fail to state which quantities define cutting ability in your eyes. As I illustrated, the edgeangle is the same so for *very* shallow cuts the cutting ability will be the same, the width behind the edge is the same so for shallow cuts the cutting ability will be the same and since the spine thinkness is the same, for through cuts the cutting ability will also be very similar. So your statement must refer to something in between. Please explain what kind of geometries you are comparing here. And who is advocating this as optimal? I have been on this board for a while now, and I have never seen anyone advocating a relief grind over a blade properly ground from the spine down like Tom Krein does.

This is a discussion board, but lately you don't discuss, but only give lapidary answers and my intelligence feels a bit insulted. What happened, Cliff? I don't think I am a troll, why don't I deserve more a grand total of three sentences. I spend considerably more effort to explain my problems with your statements.
 
HoB said:
Cliff, my question is absolutely answerable and I did not misquote you either.
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Hob, you removed the critical clause and thus the statement was then undefined.

Also you fail to state which quantities define cutting ability in your eyes.
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I have been measuring cutting ability and noting the results for ten years. I even have a detailed webpage where I give a number of tests I use and how they measure cutting ability and what is the manner of quantification. This seems fairly ridiculus, I would expect this from db.


Please explain what kind of geometries you are comparing here.
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A knife with an edge relief vs a primary grind recut, that is what we are discussing. Since the edge will be thicker on a knife with a edge relief the angle has to be more acute to have the same level of cutting ability (as an average of distances around the edge bevel). This more acute edge angle means for sub-edge level impacts (ie., no primary grind penetration), the durability will be lower. Now for large tactical (non-cutting knives) you actually want an edge relief instead of a pure optimal primary grind because those knives can get overloaded severely and if this happens the large and thick relief will protect the primary grind from blowouts. But again this isn't a cutting viewpoint and even then you still want to carefully optomize the primary grind.

And who is advocating this as optimal?
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Many which is why I note it is the worse way to solve the problem in general. If you really are unaware of this I can pull up some links, but this seem fairly absurd.

-Cliff
 
To be fair, I'd say a relief grind is about the best solution for the situations generally posed. When someone asks what to do with knife X in their collection, spending a few minutes cutting a relief with their sharpening stones is probably more plausible than asking the person to get a piece of power equipment and practice, or pay what may be a sizable portion of the cost of the knife to ship it to someone like Tom for a regrind. Even sharpening flat to the stone may be too damaging to the appearance of the knife, or require more work than is reasonable to the individual. Of course, there's also suggesting a knife with better geometry for the task, but that again doesn't really address the question about what a particular user should do with a particular knife to improve cutting performance. When a guy wants his knife to look the same, but 'cut better', it's a bit limiting.
 
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