This Throwing Knife Launcher Is an Amazing and Terrifying Feat of Engineering

Do not try this at home, even if you run a popular YouTube channel about science.

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Steven Seagal makes knife throwing look effortless in movies like Under Siege, but it’s actually an incredibly hard skill to master if you don’t have Hollywood’s movie magic helping you out. That’s what Quint, of the YouTube channel Quint BUILDs, was lacking. But with some good old fashioned engineering, they managed to build a handheld throwing knife launcher that reliably hit their target from varying distances.

Jeff Goldblum’s “Your scientists were so preoccupied with whether or not they could, they didn’t stop to think if they should,” is what comes to my mind here. That apparently wasn’t the case with Quint, though, because after months of designing, redesigning, programming, and reprogramming, the YouTuber’s built one of the most impressively terrifying pieces of amateur engineering we’ve ever seen.

Knife Throwing Machine!

Once you learn to hit a target with an arrow, hitting it again from varying angles and distances is relatively easy with some minor aim adjustments. That’s not the case when throwing knives. Added spin is needed to give the knife enough kinetic energy to embed itself into a target, with a specific number of rotations needed to ensure its sharp tip hits the target first, not the flat side or blunt handle. If you’ve ever been axe throwing, you’ll know what we’re talking about.

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As with many other talented makers and hardware hackers on YouTube, Quint decided that brute force engineering was a better alternative to diligent practice, so they created a handheld launcher that uses high-performance servo motors, solenoids, custom 3D-printed components, and some heavy batteries to hurl throwing knives with the right amount of spin so they hit the mark and stick every single time. To allow the launcher to work from varying distances, the launcher even employs a LiDAR sensor that’s used to measure how far away the target is and adjust its green targeting laser appropriately.

It appears to work almost flawlessly, launching knives from a magazine as quickly as the machine can reset itself and Quint can pull the trigger. Steven Seagal might finally have some stiff competition for Under Siege 3.