Small dent in spine of blade - will it weaken the blade?

T

Toivo

Joined
Jan 27, 2018
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Here is a classic “I want reassurance that I didn’t fuck up my knife” post.
Got a beautiful quiet carry drift. It fell about 2.5 feet onto tile. No functional damage, but I noticed a few very small dents on the spine of the blade. Curious if the metallurgists here can tell me if this type of dent will cause the blade to be weaker overall. Perhaps worth mentioning is that it is vanax in thin blade stock (.09 inches).

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Lol no way. That’s such a small dent that the 0.09 blade thickness looks giant by comparison. You’d get a bigger stress riser from the sharpening choil, if you had one, and even then you’d have nothing to worry about.

0.09 is also fairly substantial by my standards. Thicker than your average mora.
 
Doubtful; there are a lot of knives out there on the market that have giant portions of the spine removed to make ultra large thumb holes. Some are now even long slots that go halfway down the spine itself.

Probably the first place to hear of them failing would be here, and since many have been out for a couple of years now and we haven't heard any screaming, I think you're probably okay!
 
Considering a dent is similar to the Rockwell hardness test (as far as I understand it anyway), I would assume the blade steel is on the soft side to sent that easily granted the tile may be harder than the steel. In my review of the Rockstead SHU (post #7) I show a picture of the “dent” they leave between the ricasso and the tang which is apparently to test the hardness.
 
EngrSorenson said:
Lol no way. That’s such a small dent that the 0.09 blade thickness looks giant by comparison. You’d get a bigger stress riser from the sharpening choil, if you had one, and even then you’d have nothing to worry about.

0.09 is also fairly substantial by my standards. Thicker than your average mora.
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Interesting. I was wondering if maybe the denting force would scramble the metal grains (like what happens with forging prior to normalizing) in a way that was worse than something like a sharpening choil or jimping that looks more like a cut, rather than a blunt force. But it sounds like that’s not much of an issue. I know work hardening or cold forging can also toughen steel depending on its structure.
 
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midnight flyer said:
Doubtful; there are a lot of knives out there on the market that have giant portions of the spine removed to make ultra large thumb holes. Some are now even long slots that go halfway down the spine itself.

Probably the first place to hear of them failing would be here, and since many have been out for a couple of years now and we haven't heard any screaming, I think you're probably okay!
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True, but those are enclosed openings. Anything on the outer periphery of the blade will be more likely to lead to a catastrophic failure. (e.g. badly done jimpings or serrations.)
 
Dent? What dent? If it didn't break or cause a crack already, it shouldn't be a problem.

If you're worried about dents damaging your blade(s), you should switch to a plain old carbon steel blade like this.

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Inherited it (among many other knves) from my parents who beat the :poop: out of it w/no negative consequences. LOL! ;)

Bottom line: Harder steels have a greater probability of breaking due to less "toughness," while softer steels that have greater "toughness" are less like to break.

Then again, harder steels will hold their edges better, while softer steels do not. However, personally, I have no problem sharpening a softer steel blade when it gets dull, especially given how difficult it can be to resharpen harder steels.

Every thing is a trade off.
 
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Toivo said:
Interesting. I was wondering if maybe the denting force would scramble the metal grains (like what happens with forging prior to normalizing) in a way that was worse than something like a sharpening choil or jimping that looks more like a cut, rather than a blunt force. But it sounds like that’s not much of an issue. I know work hardening or cold forging can also toughen steel depending on its structure.
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Technically true, but it’s so localized and small that you’d never register any internal stress caused by the plastic deformation of the steel in any practical usage.
 
MolokaiRider said:
It's kinda strange to see it even dented.
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A youtuber measured the hardness of this model at about 57 rockwell, so it is not extremely hard, but should be very tough at that hardness so that kinda explains the dent as opposed to scratch or break.
 
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