[HN Gopher] Knife Throwing Machine (2022) [video]
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Knife Throwing Machine (2022) [video]
Author : zdw
Score : 75 points
Date : 2023-07-27 18:25 UTC (1 days ago)
(HTM) web link (www.youtube.com)
(TXT) w3m dump (www.youtube.com)
| jonas21 wrote:
| I can imagine being the neighbor on the other side of that fence.
|
| ( _peeks head over fence_ ) Hey neighbor, what's that thumping
| sound I've been hearing all day?
|
| Oh, that? Just my knife throwing machine. Nothing to worry about
| - I've worked out all the math, and my smart 13-year-old wrote
| the code, and there's plenty of safety margin with this little
| block of wood I've mounted on the fence to absorb the knives. And
| the machine has only activated without anyone telling it to once
| or twice. Like I said, nothing to worry about!
| kobalsky wrote:
| I loved the project but I couldn't stop thinking about a knife
| flying over that fence, or getting shot backwards (that thing
| returned pretty fast). It would have been more sensible to put
| the block of wood on the side of their house.
| micromacrofoot wrote:
| This is very cool home engineering, and maybe I'm getting soft in
| my old age... but whenever I see something like this I have to
| wonder "why violence." I guess it's some inherent trait we have.
| wlesieutre wrote:
| He has other videos like a pumpkin carving robot, gunpowder-
| powered home run bat, and a self-aiming pool cue
|
| https://www.youtube.com/watch?v=X9zXcnSXNF0
|
| https://www.youtube.com/watch?v=Puo6Vgcbxps
|
| https://www.youtube.com/watch?v=vsTTXYxydOE
| expertentipp wrote:
| The ads are so obnoxious and unskippable that I prefer to
| close the tab even at the price of missing to watch educating
| and substantive content. No, I'm not going to buy Youtube
| Premium.
| Ukudala wrote:
| Unsure your platform, you may want to check out Vinegar if
| on Mac or iOS: https://apps.apple.com/us/app/vinegar-tube-
| cleaner/id1591303...
| [deleted]
| micromacrofoot wrote:
| Thank you :)
| bcook wrote:
| As someone who has carried a pocket knife for most of my life,
| I very rarely think of the knife as a weapon. When I was
| younger, me and my friends would throw knives at trees.
| Sometimes we would throw hatchets at trees. It's fun and very
| satisfying to finally stick the knife/hatchet.
|
| Violence was never in my thoughts.
| fluoridation wrote:
| It probably could have been simpler and lighter if it accelerated
| the knife using rollers like a baseball throwing machine. It
| would have also eliminated the problem of calculating how much to
| spin the knife.
| dsr_ wrote:
| Knives are not particularly aerodynamically stable. (Not these,
| anyway.) They need some spin to avoid tumbling erratically.
|
| Nobody cares which point on a baseball hits the bat, although
| they do care about spin because it contributes to path changes
| via aerodynamic effects.
| Someone wrote:
| I don't think the typical knife is stable in flight that way.
|
| In my layman's physics, the knife edge will keep pointing
| forwards if the knife handle would decelerate faster than the
| knife blade, when thrown that way in isolation.
|
| So, you either need more mass in the knife blade or more air
| resistance in the knife handle to get that.
| siliconc0w wrote:
| Stuff Made Here (https://www.youtube.com/@StuffMadeHere) also has
| a lot of similar content which is pretty great. Really respect
| the generalist skillet that can pull of these kinds of
| complicated projects.
| mrguyorama wrote:
| StuffMadeHere actually spends some time here on HN
| occasionally. I don't remember his user.
| dralley wrote:
| https://news.ycombinator.com/user?id=swighton
| jihadjihad wrote:
| Ah, no, I can't click...I know I am going to be nerd sniped if
| I do and I have stuff to finish!
|
| Some of my favorite stuff on YT by far.
| decker wrote:
| Pretty neat, but I wish they would have emphasized safety a bit
| more and put up a full sheet of plywood behind the target.
| LorenzoGood wrote:
| Yeah they really could have taken out the neighbors through
| that fence.
| reaperman wrote:
| I believe it would be slightly more optimal if the knife only
| rotated 1/2 of a rotation. That's what I always aimed for when I
| was practicing throwing knives, based on the logic that less
| angular velocity would provide a longer "sweet spot" time during
| which the knife would be at the optimum angle for deeper
| penetration, so if the rotation speed was off by a little bit it
| would still be closer than it would be if the rotation speed was
| "off" by the same absolute amount but with a 3x-6x faster
| rotation speed.
| adrian_b wrote:
| In the third video of this series they show an improved version
| where before throwing the knife one can choose the number of
| rotations, down to the minimum value of 1/2 of a rotation.
| muxator wrote:
| Now I know I'll never be half the father this guy is!
| browslee wrote:
| [flagged]
| samstave wrote:
| Ive been thowing knives for 30+ years
|
| but a robot knife thrower is not the same in intrinsic priciple
| as to WHY we throw knives...
|
| Its subtle but significant. The movement of throwing a knife is
| very same to throwing a person, that is ; the physical body
| movements of throwing a knife are the same as the movements of
| throwing a person, swingin a sword etc...
|
| They are movements designed to train you when you dont have an
| Uki.
|
| Here is me at ~60 feet, knife on knife. But this movement is the
| same as several throws in Bujinkan.
|
| https://www.youtube.com/watch?v=ks_sBg85suA
|
| Its all in the hips.
|
| Check out Flying Steel and r/throwing
|
| Unrelated but still fun ;
|
| https://www.youtube.com/watch?v=u3I6lbpF68Q
| h2odragon wrote:
| If I may ask the question you're answering: throwing a knife is
| almost never an effective attack. distraction, yes; but it
| seems a silly thing to do in actual training.
|
| As you say, however, knife throwing is very useful as training
| for throwing _anything_ else. With knives you 've got to have
| so much so close to perfect for it to work at all. When you
| throw a rock the number of important variables is much lower;
| but what you've learned with the knives still serves you well.
| samstave wrote:
| This is basically correct, the factors that you focus on when
| throwing a knife are the same factors you take focus upon
| when throwing a human.
|
| The visuals are the arms, but the core is the hips and their
| placement.
|
| When you watch me in that all distance vid, you see that the
| real power comes from the hip rotation, but the precision
| comes from the upper shoulder displacement. Thus the training
| of the hips sans Uki.
|
| This was my professor ;
|
| https://www.usadojo.com/larry-cary/
|
| Ive trained with every single person in these photos...
|
| Recently my best friend and training partner got back from
| Israel where he was doing some akban training...
| https://www.youtube.com/@AkbanOrg/videos
|
| We've been training with them since ~1989 - but these are the
| movement styles that map with arts, aside from pure bujinkan
| movements such like our Soke, Hatsumi - but there is a cadre
| of bad-ass ninjutsu folks in the US, no not richard
| whatevere...
|
| but look up van donk, hatsumi, and others in akban, krav maga
| and bujinkan.
|
| --
|
| There are several throwing style - spin, no-spin, spike
| (which is the same as no spin) but here is an example of me
| in my garage
|
| https://www.youtube.com/watch?v=KtCYnjeaog4
|
| (Also this was handle thrown, which implies no-spin.... but
| honestly spin throw, blade held is my preference, this is why
| you see me wearing gloves in vids... Never throw a knife
| without PPE (gloves)
|
| Trust me - being sliced by a knife leaving your grip at
| velocity is no fun.
|
| EDIT: Oh Yeah - always grind down the edges of any knife you
| intent to throw.
|
| The only thing that matters is the pointy part. And the mass
| of the knife and your skill. The cutting part does not
| matter.
|
| Do you know why Katanas were curved, because they got more
| cutting edge ratio with a single pull/strike.
|
| throwing is about puncture, hence stars and blah - and its a
| portion of why ninjatos were straight - because they were
| designed for piercing in small enclosures (hallways)
|
| The movements are designed around the "small circle jujitsu"
| principles as booked by wally jay - not only was he a teacher
| of mine he was a neighbor and we lived 2 blocks from him in
| Alameda..
| nicechianti wrote:
| [dead]
| Saulivar wrote:
| This guy should win dad of the year award. Seriously. I gave my
| son a knife for his birthday when he was 7, but this is taking to
| a whole another dimension. I should also mention that growing up
| in eastern Europe back in the day, when I was 14, I was building
| a gun in my bedroom. It blew a hole in my palm when I was
| testing.
| BohdanPetryshyn wrote:
| I didn't know why I might want to have a kid one day. This
| channel answers this question and also shows a good and a fun way
| to raise a smart child!
| the_third_wave wrote:
| That assumes your child will pick up your interests which is
| certainly not guaranteed - mine sure did not even though I did
| try to engage them in similar (though less high-tech) exploits.
| I have two daughters who both grow up liking typical daughter-
| things like horses (which is not that odd given that my wife is
| a horse vet and we have 3 of the critters around the farm) and
| books instead of all those noisy smelly dangerous things I'm
| wont to play with. I did manage to build a three-wheeled
| soapbox car with my oldest daughter with which she then
| competed - and won - a soapbox race, the thing was loosely
| shaped like a bee and painted to resemble one, bug eyes
| included (bubble plastic with some red spray paint does
| wonders). It had Ackerman steering (cobbled together using
| rebar and welded-on nuts for bearings) and was dangerously
| fast, just the way those thing should be.
| placesalt wrote:
| "Because it measures in the infrared, it even works in the
| /dark/"
|
| No, because it's an active rather than passive light sensor, it
| works in the dark.
|
| Edit: also, the fact that you can see a green dot heavily implies
| the sensor is operating in the green wavelengths, not in the
| infrared, but that's secondary.
| adrian_b wrote:
| While you are right about the active light sensor, it is likely
| that the sensor really works in the infrared.
|
| The green laser beam must be in addition to the infrared beam,
| with the purpose of allowing a human to choose the aiming spot.
| jdlshore wrote:
| It uses LiDAR. The green dot is an aiming laser for the human,
| and is calculated from the LiDAR result.
| placesalt wrote:
| You can use the green part of the spectrum for LiDAR. It's
| what they use for bathymetric LiDAR.
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(page generated 2023-07-28 23:01 UTC)