A sharp knife is a safe knife

By » Tue, December 6 2011

Drinking and knife-wielding go together like gin and eggnog. But that doesn’t mean sometimes, after slamming a horrible, disgusting cocktail just to avoid pouring perfectly-good liquor down the drain, you decide it’s time to make yourself a late-night snack. Learn from my fail.

Have you ever seen a knife’s edge under a microscope? It doesn’t look sharp. It looks like this:

1000x sharp A sharp knife is a safe knife

That’s at 1000x magnification, where ten microns (μ) is 0.0039th of an inch. This is a dull edge:

1000x dull A sharp knife is a safe knife

And that’s on a wood-working blade. On a kitchen knife it’s thinner, and the edge is all saw teeth. A sharp knife is safer for two reasons.

First, it’s much easier to control. Since the blade can cut through stuff with less resistance, you use less force, which means if you screw up, you’re not putting a lot of energy behind it, and the sharp knife won’t go far when it’s out of control.

But in the event that you slash a digit clean across, the sharp blade will do less damage to the tissue it does flay. It means that your laceration will be clean.

henckels 580 mbd102010 A sharp knife is a safe knife

Henckels Damascus. Pretty!

A jagged edge will do a lot more tissue damage which hurts more, for starters. I hit my knives with a steel on a regular basis, so they’re sufficiently sharp; so sharp that I didn’t realize I’d slit open my middle finger–across the finger pad, no less–it was the blood that gave it away. And there was a lot of it, given the capillary-flushing side-effect of boozohol.

1.1318435322.boozahol A sharp knife is a safe knife

Just an aside, there must be some property of stainless steel that affects the oxidation of blood; it was all over the sink in an electric shade of red. Either that or the aforementioned drinking.

It didn’t hurt at all. The bleeding was so bad I had to tourniquet my finger to get it to stop, but I’ll be damned if it wasn’t the cold, pH-neutral water that hurt (blood is alkaline, so water, to your insides, is acidic-feeling, and that’s why it hurts).

When it did stop bleeding, I hit it with some skin glue, and that burned like nothing else that’s ever been in my bloodstream. (To be fair, my blood rarely sees anything foreign in it other than ethanol, but still. The pain was indescribable for what it was.)

Which highlights another thing: it didn’t just not hurt at first because I’d pre-numbed my system. I could feel pain just fine, but the cut wasn’t an issue. And despite the vesuvian bleeding, I didn’t cut so deep I nicked a nerve. It was just a super-clean cut.

red and white blood cell and p A sharp knife is a safe knife

Clean being a literal reason sharp=safe. Because the tissue damage is limited, the cut is far less likely to get infected; pressed shut, the injury still gets the blood, oxygen, and lymph it needs to heal, and the total number of skin cells that are otherwise be candidates for infection are fewer. Less tissue damage means lower risk of infection and faster heal times.

You shouldn’t drink and knive. But always keep your knives sharp. And buy some skin glue.

Protip #2: A falling knife has no handle.*

*Does not seem to apply to jugglers.

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