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- Jun 16, 2009
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I have a nice piece of D2 that I need to make a couple of blanks out of. I want the design to have the ability to cut bone, yet stay sharp enough to trim fat.
Any Tips?
Any Tips?
-
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Working with D2
- Thread starter jkil-cutlery
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I have a similar order from a hunter and a butcher. He wants a knife that is able to cut bone while being able to trim. I will go for differential edge thickness on my blade, looks like a big skinner, trailing tip with a good curve. I will do it also out of my D2 stock. The thickness of edge will be meaty at the back - close to plunge cut, and gradually it will be very thin, almost zero edge towards the tip. That way he will be sure that the edge can take abuse when chopping, while he can be sure that the tip area staying very sharp and easily trim...
The profile I am thinking about is something like that, it will be a lot longer though - will be about 6" blade length: http://www.bladegallery.com/shopexd.asp?id=87054
The profile I am thinking about is something like that, it will be a lot longer though - will be about 6" blade length: http://www.bladegallery.com/shopexd.asp?id=87054
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- May 4, 2009
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Jkil,What is the width and thickness of your D-2 ?
Nathan the Machinist
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D2 is capable of doing this. The edge stability of D2 is all over the place, from better than any stainless steel to absolutely miserable. HT is key, and it is easy to do badly. I suggest search this forum on D2 HT and edge stability.
I have a knife here made by Jim Viall in D2, and another made by Bob Dozer that I recently put through extensive testing that both displayed edge stability in hardwood that I'm confident could be hammered through live bone without edge roll or chipping despite their relatively thin edge (under .020") and acute sharpening angle.
Other D2 knives at similar harness suffer edge damage that is visible at an arm's length. It is all in how you prevent or convert excessive retained austenite which can easily be 15% in this steel. I use cryo before any temper.
Bob Dozer says he does not use cryo to convert retained austenite. I have evaluated his HT and I respect the quality of his HT and entire package. I talked to him in Atlanta at the show a few weeks ago and he said that RA is not a big deal and he doesn't need to use cryo. He also says his knives don't rust as bad as most D2. That means his HT has more free chrome, meaning he didn't skimp on austenitizing time or temp, and didn't get carried away with his tempering temp (the other way to convert RA). So I don't know how he prevents RA from ruining the party without cryo and he won't say.
Paul Bos does use cryo on his standard D2 HT. He also generally uses a snap temper before cryo to prevent cracking people's knives. This D2 HT does not work as well as the Dozer. But if you ask him to skip the snap temper the results are as good as the Dozers (in my testing) which are also my own HT and Jim's.
It isn't rocket science, but I'd wager that most folks aren't getting the best results with D2. And D2, done badly, takes a lousy edge and holds it forever.
But my back medicine is making me loopy - I'd probably better get off the interwebs before I stick my foot in my mouth...
I have a knife here made by Jim Viall in D2, and another made by Bob Dozer that I recently put through extensive testing that both displayed edge stability in hardwood that I'm confident could be hammered through live bone without edge roll or chipping despite their relatively thin edge (under .020") and acute sharpening angle.
Other D2 knives at similar harness suffer edge damage that is visible at an arm's length. It is all in how you prevent or convert excessive retained austenite which can easily be 15% in this steel. I use cryo before any temper.
Bob Dozer says he does not use cryo to convert retained austenite. I have evaluated his HT and I respect the quality of his HT and entire package. I talked to him in Atlanta at the show a few weeks ago and he said that RA is not a big deal and he doesn't need to use cryo. He also says his knives don't rust as bad as most D2. That means his HT has more free chrome, meaning he didn't skimp on austenitizing time or temp, and didn't get carried away with his tempering temp (the other way to convert RA). So I don't know how he prevents RA from ruining the party without cryo and he won't say.
Paul Bos does use cryo on his standard D2 HT. He also generally uses a snap temper before cryo to prevent cracking people's knives. This D2 HT does not work as well as the Dozer. But if you ask him to skip the snap temper the results are as good as the Dozers (in my testing) which are also my own HT and Jim's.
It isn't rocket science, but I'd wager that most folks aren't getting the best results with D2. And D2, done badly, takes a lousy edge and holds it forever.
But my back medicine is making me loopy - I'd probably better get off the interwebs before I stick my foot in my mouth...
Last edited:
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I've stocked up on a bit of D2 and CPMD2, because it seems like a good compromise between stainless and carbon steels. Being pretty darn new, I haven't HT'ed any yet, and will likely have my first few HT'ed by a pro like Bos. That way I'll have a trustworthy "standard" to judge against.
I like the idea of a differential or compound edge for those purposes. My biggest concern would be that it will require careful hand-sharpening to maintain. Some customers don't want to deal with that and prefer SharpMakers and the like, that help assure a constant edge angle all along the blade. Of course, the same can be said of convex edges.
If the customer is OK with that, it seems worth looking into.
It may also be true that a fairly standard angle, say 20degrees per side, would be thick enough to handle batonning through bone or hard wood on the straight part of the edge, but since the belly/tip won't likely be subjected to that, it will still keep a fine, although somewhat obtuse edge that's plenty sharp enough for fine trimming/skinning work? I'm guessing that would depend a lot on the HT, and subsequent "fineness" of the edge. The fineness and consistency is why I ponied up for the CPM version of the steel.
Nathan, I was hoping you'd chime in, because you've taught me a lot about D2. Thanks for sharing! Your quote about "a lousy edge forever" seems to be the only major beef most people have about D2.
The more I learn, the more I realize I have more to learn. I'm fascinated with the ways different HT techniques can effect edge-holding, stability and "sharpenability."
I like the idea of a differential or compound edge for those purposes. My biggest concern would be that it will require careful hand-sharpening to maintain. Some customers don't want to deal with that and prefer SharpMakers and the like, that help assure a constant edge angle all along the blade. Of course, the same can be said of convex edges.
If the customer is OK with that, it seems worth looking into.
It may also be true that a fairly standard angle, say 20degrees per side, would be thick enough to handle batonning through bone or hard wood on the straight part of the edge, but since the belly/tip won't likely be subjected to that, it will still keep a fine, although somewhat obtuse edge that's plenty sharp enough for fine trimming/skinning work? I'm guessing that would depend a lot on the HT, and subsequent "fineness" of the edge. The fineness and consistency is why I ponied up for the CPM version of the steel.
Nathan, I was hoping you'd chime in, because you've taught me a lot about D2. Thanks for sharing! Your quote about "a lousy edge forever" seems to be the only major beef most people have about D2.
The more I learn, the more I realize I have more to learn. I'm fascinated with the ways different HT techniques can effect edge-holding, stability and "sharpenability."
Last edited:
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I am planning to keep the edge angle same on all over the blade but I plan to vary the edge thickness. This way the sharpening angle will be the same for the reason you just stated. Though the tip will be sharpened much quickly than the plunge side. I should think about that I guess
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The thickness looks to be about .20", I will have to get the caliper out and measure. But the width is 4". I will probably have to do some more research to see what my options are for cutting and shaping out the profile.
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I will definitley have to give this some more thought since a lot of people reccomend cryo on D2 and my only experience with HT blades is with low carbon and chromolly.
Chances are, if this build is going to be worth the effort, I may get the blank shaped out and then send it off for HT. (providing it doesn't cost too much)
Chances are, if this build is going to be worth the effort, I may get the blank shaped out and then send it off for HT. (providing it doesn't cost too much)
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Oh, I see. I think your idea is better, or at least easier to maintain, than an actual compound edge.
TKS will do it for around $10/blade plus shipping, including cryo.