K390 Chipping, how long till "good steel"?

E

elevator man

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So what are yalls experiences with new knives regarding sharpenings till reaching "good" steel? I've got a new endela in k390 I've sharpened 2 or 3 times in the month and a half ive owned it, and I've had serious chipping on all 3 edges. From minor things like tapping a flashlight clip after cutting through thick tape. This knife I have sharpened to 30 degrees which I think is reasonable for a tool steel. Also I have another k390 knife and a 15v knife that I've used hard for 8 months and I've never seen one singular chip out of either of those knives. Not one. Those two also sharpened to the same 30 degrees.

My question is, is it reasonable to expect with a few more sharpenings to see the steel start performing like a tough (relative) tool steel or is it likely the heat treat on this knife was just done in a way it lost alot of the toughness it should have? I can take it to 40 degrees but loath the idea, I much prefer the cutting of 30.
 
One other thing, the factory bevel on this knife was roughly 15 on one side and roughly 10 or maybe 12 on the other. I still don't have the factory bevel fully removed yet, still two main bevels on that side
 
I’ve got very little experience with k390 - the Endura I’ve been carrying for a few months hasn’t chipped once though. I basically use the Endura for breaking down heavy boxes exclusively.. no issues with the K390 chipping. I’m also still using factory edge.

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My Rex45 shaman had chipping issues. I have a lot of other spydercos and only that one chipped. Not sure what to tell you other than after sharpening out 3-4 chips it hasn't chipped since. I would say that the knife is a solid 1/8" shorter than factory.

I didn't buy another Spyderco for a while. I haven't had a chipping issue since, I am going to knock on some wood.
 
SwissHeritageCo said:
When you say that you've sharpened it 2-3 times, are we talking touch ups or proper sharpenings?

In my experience it can take a few heavy sharpening sessions to get past the overheated steel.
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Great point. The answer to that question might make all the difference.

I've never had an issue with K390 chipping in my Spydercos, so I'm surprised to hear this happened. I would stick with it and keep sharpening until the problem stopped. No real way to know how many licks it'll take until you start licking in earnest.

If that's more than you're willing to do then reach out to Spyderco.
 
If you haven't fully removed the factory edge, that might explain why you're still having chipping issues. Some knives just get burned in sharpening more than others and will require more sharpenings to get to good steel.
 
Yall are making me a little more sure. I too have had no chipping at all from k390 on a different knife. This ones been consistently chipping. Large chips. Anyhow by sharpening I mean proper sharpenings raising a burr on a coarse stone and going to finer stones.

I guess I'll keep sharpening it and using it and see how it does. I just wasn't sure if it was a burnt edge from grinding how many sharpenings might be typical before getting to "good" unburnt steel. Or it could just be the heat treat all the way through
 
marrenmiller said:
If you haven't fully removed the factory edge, that might explain why you're still having chipping issues. Some knives just get burned in sharpening more than others and will require more sharpenings to get to good steel.
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I hope your right. I love the knife itself and it is sentimental to me as an engraved gift from my wife
 
It isn't a very tough steel. It is a high wear steel and toughness and corrosion resistance is not all that great. All knife blades edges will fail at some point. If you have edge failure you should change the edge geometry to suit your needs and forget about chasing down "good steel" that wasn't overheated. That is mostly a myth IME. It can happen, without a doubt. It's not all that common in real life with companies that grind / sharpen with coolant like Spyderco does. Forget about what my knife or anybody else's knife does . We all are different and use and care for knives differently so whether my knife chips or not ( My K390 Spydercos will easily pit but have never chipped or bent) means nothing.
 
I have a 20cv manix that would chip on just about anything. I was blaming the steel, I was avoiding m390 and the like for years.

It took about 8 sharpening sessions and now I really enjoy the knife.
Painful until you reach the good steel, but it is in there.
 
My biggest gripe with Spyderco is the factory edge out of the box. Since moving to robotic sharpening the edges are always uneven on Golden made knives. I wouldn't put it past a robot that it grinded to much material getting the edge to hot even with coolant.
 
I'm really hoping that's the issue here. Love the knife, it'd be a bummer if it was the heat treat all the way through. Holding out hope and sharpening it again now and I'll see how she does. But on your point the very low factory angles of roughly 10 on one side and 15 on the other made me think a burnt edge could be possible. We'll see if more sharpening changes it at all.
 
I chip my K390 Endela all the time. If you exceed the yield strength of the steel from force in use and or have thin edge geometry it happens.
 
Seedy Lot said:
I chip my K390 Endela all the time. If you exceed the yield strength of the steel from force in use and or have thin edge geometry it happens.
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Out of curiosity, what sorts of activities tend to cause the most chips in your Endela? Not criticizing, just curious.
 
oldmanwilly said:
Out of curiosity, what sorts of activities tend to cause the most chips in your Endela? Not criticizing, just curious.
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Side loading the edge with pruning cuts in the farm and same with weeding woody shrubs with the knife. Not big chips, micro, but happens regularly enough. I could sharpen with more obtuse edge geometry and not have an issue but like the way it cuts with a thinner edge.

The toughness of K390 is on the low side for me and has higher carbide volume than I usually like for edge stability but it is working out well enough. Not hard to sharpen out the micro chips on diamond plates.
 
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