Over the past few years, I have learned a lot about knives through Youtube, other websites, personal experience, and you guys here on BF. Usually when I see someone test the lock of a folding knife in a video, they'll start out with a spine whack test, then they'll do overstrike tests (I could be using the wrong term here). They'll take the knife and hit it against the board or table with the handle, usually around the first finger choil. What does this test? The lock or the handles strength? If it's the lock, I don't understand how this would put stress on the lock, so please explain. Thanks!
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What do overstrike tests really test on a knife's strength?
- Thread starter jmflem
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The overstrike test stresses the lock. Since the knife folds in the middle, when the handle stops (as it hits the board) the blade wants to keep going and fold up. If it does, the lock has failed... That being said, I think tests like that are just for shock value, or to impress people. I have never hit anything with a folder in that manner. I don't chop with "broken knives".
Charr
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I sort of understand why people perform these tests, but most of them really don't have any functional value, like AntDog said.
People want to believe that their knife will handle things that realistically aren't going to happen, like batoning with a folder. In the extremely unlikely case that you actually have to do that, one thing that most people never even think of when they do their tests is that you can simply disengage the lock of the knife and baton that way. If you do that, the lock becomes irrelevant, and the blade supports almost 100% of the shock, which honestly most decent-sized blades can handle for a decent number of hits.
In terms of the overstrike test specifically, I don't think it's the most reasonable of tests either, since most people with some common sense on how to use their knives shouldn't come into a situation where the overstrike can really occur. Sure, it sort of tests how the lock handles heavy vibration due to impact, but there isn't a whole lot of that happening for most knives, and the ones it does happen to are usually fixed blades (or probably should be).
Most people have very little scope of what their knives can handle anymore because people tend to do these very over-the-top tests. Really, most well-made folders can easily accommodate the tasks that 99% of people need them to. You don't really need a knife that you can hammer in a nail with. Sure, it's kinda cool that it can, but honestly, it's a knife, not a hammer, not a pry-bar, a knife, and its made to cut.
People want to believe that their knife will handle things that realistically aren't going to happen, like batoning with a folder. In the extremely unlikely case that you actually have to do that, one thing that most people never even think of when they do their tests is that you can simply disengage the lock of the knife and baton that way. If you do that, the lock becomes irrelevant, and the blade supports almost 100% of the shock, which honestly most decent-sized blades can handle for a decent number of hits.
In terms of the overstrike test specifically, I don't think it's the most reasonable of tests either, since most people with some common sense on how to use their knives shouldn't come into a situation where the overstrike can really occur. Sure, it sort of tests how the lock handles heavy vibration due to impact, but there isn't a whole lot of that happening for most knives, and the ones it does happen to are usually fixed blades (or probably should be).
Most people have very little scope of what their knives can handle anymore because people tend to do these very over-the-top tests. Really, most well-made folders can easily accommodate the tasks that 99% of people need them to. You don't really need a knife that you can hammer in a nail with. Sure, it's kinda cool that it can, but honestly, it's a knife, not a hammer, not a pry-bar, a knife, and its made to cut.
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Charr
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Sorry you're right we kinda wondered off there 
By impacting onto the handle and providing momentum to the blade to swing closed as well as vibrating and shocking the lock itself.
In the case of a frame-lock, these tests see if the lockbar will slip over when an impact hits and causes the lockbar to unseat itself form the tang of the blade. In the case of something more like a button or axis-style lock, it really just tests the lock under impact vibrations.
I see it used more on less-expensinve steel liner locks and such that may seem to have a weaker lockbar because the shock could reasonably cause the lock to slip off and the blade could close. In most decent folders the locks are under enough tension that it really isn't a concern though.
By impacting onto the handle and providing momentum to the blade to swing closed as well as vibrating and shocking the lock itself.
In the case of a frame-lock, these tests see if the lockbar will slip over when an impact hits and causes the lockbar to unseat itself form the tang of the blade. In the case of something more like a button or axis-style lock, it really just tests the lock under impact vibrations.
I see it used more on less-expensinve steel liner locks and such that may seem to have a weaker lockbar because the shock could reasonably cause the lock to slip off and the blade could close. In most decent folders the locks are under enough tension that it really isn't a concern though.
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Did you read my post? I answered you.
The handle stops when it hits the board. The blade has all that inertia carrying it forward. The blade wants to keep going. If the blade keeps going, the knife folds up, and the test is failed.
What keeps the blade from closing on a folding knife? The lock. Therefore it's supposed to be a shock test of the locking mechanism.
The spine whack "test" does the same thing except with direct force instead of inertia. Basically you are trying to see if the knife can withstand different stresses without the lock failing.
I don't do any of that silliness with my knives. If the blade feels like it's locked open solidly, that's good enough for me. I don't go whacking on it to prove it.
You did answer me...sorry. It just seemed like everyone else wasn't, and I wanted some other peoples opinions too. Thanks everyone, now I understand it.
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No worries man! Just didn't know if you had seen it or not.
Some things are based on opinions, but the purpose and outcome of this test is not an opinion. The purpose is to see if the lock will fail. The outcome is either failure, or pass.
I still think it's silly, and I wouldn't recommend that anybody do it. It's not necessary.
toker
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I think most if us agree that these kinds of tests don't actually show whether or not the lock will actually fail in realistic use. That's why these particular tests don't make any sense.