I think you're actually missing the most important effect of the twist. See, once the twist begins and we enter the dynamic friction regime, the friction force can only act opposite the direction of motion. Since you're rotating the stud, then all of the friction acts about the circumference of the stud and none of it acts along the axis of the stud - you know, the direction that actually matters. The only way an axial friction force can be generated in this regime is when the stud begins to move out of the hole, but it will only be a small portion of the friction vector, and of course at that point the stud has already moved, so it coming undone is inevitable. I know a lot about this from the racing world, where people talk about the grip circle for tyres, and for instance you can manipulate the angle of force generated by sliding tyres just by changing their speed with the throttle, which is important for car control.
That actually makes a lot of sense… I wasn’t even thinking about the fact most of the friction vector would be horizontal. I guess that makes LEGO even stronger if barely any of the kinetic friction is resisting the motion but it still falls out as slowly as it does-that’s actually totally wild. Good catch, I wish I’d considered this before posting the video.
@@excrubulent But of course. When someone corrects what is clearly an overt mistake, I pin it. I just wish that I could have multiple pins because there have been a couple mistakes that were corrected by commenters… 😭😭😂
I don't think this is accurate. Motion in one direction doesn't somehow completely nullify friction in an orthogonal direction. If a block sliding along a surface were given a perpendicular shove, you wouldn't expect it to start gliding frictionlessly in that second direction.
@@wfjhDUI I didn't say it was frictionless, I said there is no component of friction in that direction until it begins to move in that direction. There is resistance, but only after movement in that direction has begun. If you want to set up a test for this using a sliding block, set up an inclined plane and place a block on that plane, then try pushing the block sideways across the plane. It will immediately begin to slide down as well as sideways. You might want to use a round puck shape for the block to eliminate certain effects created by interactions with the pushing object.
The studs are slightly conical for (1) being able to get it out of the mould and (2) for children being able to take them apart without excessive power. The bottom openings are also slightly tapered of (1), but far less than the stud.
I was wondering if that might be the case but I couldn’t find anything about a slight taper. I spent several days looking because I felt like that would make a lot of sense but I found nothing.
As a current high school physics student who didn’t quite grasp the intricacies of how friction works when we covered that, this genuinely helped me understand it better! …too bad my exam was yesterday 😔
The bigger issue is that it becomes unreliable with time as the anti-stud wears down. The friction fit you want for the play feature no longer holds, and the set fails. I have 20+ year old legos, cone pieces and studs are particularly prone to this type of failure, which are the same type of connection you would rely on.
To be fair, 20 years would be a pretty good lifetime for most other Lego play features. I doubt flick fire missiles would last that long before getting loose, spring loaded shooters would lose their tension, rubber bands rot and crumble, etc
@Nadiki to think of ot I also have several bionicle joints that have failed and a flicker that has failed as well. Though the studs have failed just from removal and placement, a play feature would increase that expectation.
Wash them in the laundrymachine in a cloth bag on low. It will reset the stresses on the most outside plastics and give the pieces a couple years second life
@BartJBols Playing devil’s advocate, it’s not a question of the commenter knowing how to address the issue personally, it’s a question of expectations Lego can set for a product they sell. If they were to use this aspect for a product, take for granted that they wouldn’t do it dependent on customers running their pieces through a washing machine.
Some of my 30 year old Lego figurines have floppy legs and spinning shoulder joints. They also have about 100.000 hours of playtime under their belt and I am very honored to pass them up for my son, when he grows old enough to appreciate the figurines automatic bow for the king feature 😂
This could be really cool with gears to extend the rotation out. A row of gears could cause one twist to release several bombs, drones, or drop pods at once!
If you control the rotation with levers that are raked by another piece you could make them drop in quick succession, like a carpet bombing manoeuvre. If you really want to show off you could even run your aircraft along zip lines with a piece in the middle to rake the levers, so it all happens automatically. Maybe even put tissue paper parachutes on the payloads for a realistic package drop. Also an array of small gears in sync would be able to hold and drop larger weights. On the end of an articulated arm it would look like one of those scrap metal cranes that hold metal with an electromagnet.
Imagine having a rig similar to your test rig, but say, times 10, and putting it on the bottom of a plane or something! You could drop a whole load of payloads form the bottom of the plane simply by spinning a component at the top and moving that rotational force with a set of gears inside the build! pretty cool discovery
Lego studs have a 0.5 deg draft angle to allow ejection from the mold. You are also missing that the total friction force is constant. When pulling directly apart, the friction is fully fighting the pull. When twisting, that force is applied against the twisting, so there is less available to fight the pulling. Think of this like how the rear tires of a car can slip sideways if the car is rear wheel drive and someone jams on the accelerator.
The clutch power could be increased to hold larger assemblies on, by making a 2x2 grid of axle holes and linking them with 8t spur gears. Add 1x1 cones to the ends of the axles to get single stud ends that each rotate with the axles. They will rotate in opposing directions but that won't affect the releasing function at all
I find this interesting but I think this has more to do with Lego having looser tolerances in their plastic these days. If you do this same experiment with pre-'00 bricks which have considerably better clutch power, they more often stay attached, even when rotated! (you may also observe how much more weight they can support in a horizontal application when using classic 1x1 snot bricks vs any modern counterpart) I doubt Lego will try to highlight this as a feature in sets since it brings so much attention to the shift in plastic quality/clutch strength. One place this effect was used nicely in Lego sets is the round stud-shooter that are included in many modern sets. They rely on the loose connecting and being slightly twisted in order to pop-off.
You explained this well enough that once you went back to the diagram of the bricks after mentioning the differences between static and kinetic friction I immediately understood what was happening without you having to explain it. This is really neat! Thank you for sharing!
This could be cool for some play features. I'm a big fan of how creative play features in lego sets can get. We'll be watching your career with great interest.
This makes sense. Although it brings back memories of how stressful all those physics classes were, lol. We can add that dynamic friction causes tiny vibrations in this case, which can cause the contacting surfaces to separate slightly over and over as you spin
Based on the fact you called them “stressful” and not “the coolest thing ever” I’m guessing you were more of an engineering guy than physics itself. 😆😂
Interesting little physics study. Though ya can't overlook the slight bevel on the edge of the studs. That bevel definitely adds to the outward "ejection" force.
i've been using legos in non conventional connections for as long as I can remember, however in general to something like that I'd have reinforced so that it does not come off (most likely to the physics you describe here). but some of the other unusual ways i'd connect things- the flats fit just perfectly between studs so you can enact a directional change in which the studs point. just connecting to one stud allows you to create a moving joint. altho you will want to reinforce it to keep things from coming apart. a single point cylinder or dot (basically only a stud on top and connector opening on bottom with as little plastic as possible inbetween), will fit just perfectly in the empty space between 4 studs arranged 2x2. a single stud will fit into those larger circles on the underside that normally act as walls to keep studs pressed into their usual place (altho with older legos it's a really tight fit). also legomen legs make for some good joint mechanics if you are short of real dedicated lego joints. as well as a decent method to change stud direction as well. with these sort of tricks i used to make mechas of all sorts with just the plain and simple legos. usually bipedal.
I would suggest a further experiment. Find a block/plate with a hole through the block where the anti-stud is, (Some technic blocks come to mind.) This would also remove the possibility that trapped pressurised air in the anti-stud has any effect. If it drops off the same speed, no effect. If it takes longer, air pressure is normally assisting.
Same with a mouth piece for a brass instrument. If i just push in my trumpet mouth piece straight in and try to pull it straight out: 1. doesn't seat well 2. is annoying to pull out. VS if you twist it in, and twist it out, it seats well and removes smoothly
I wonder if the air pressure has anything to do with it. The jumper tile has a hollow stud and even though it is tiny, there is a slight increase in air pressure between stud and antistud . Especially the round antistud in the center of the brick. Could you possibly try this inside of a vacuum chamber? Maybe you get a different result, maybe not. It might be exactly the same. With the scientific method, all the margins for error in experiments need notice. Y'know to make sure. Also there is this six shooter assembly they've been making with a similar effect. My first experience is on the Marvel Rocket mech. A very cool set. Part numbers 77257 and 77258. There's a different principle going obviously. But you will lose the studs loaded into it if you're not very careful twisting it. It's got the little round studs on one end and you spin the center piece which has a tiny point on the cylinder that pops the studs off. I like the little graphic in the instructions reminding you not to shoot your eye out ( ala "Christmas Story" ) with a Minifigure head with an eye closed inside the classic circle with a diagonal line through it. The 'don't do this' sign. The point has an angle to it that digs under like a brick separator popping it out. I've always liked the assembly but I don't shoot any of the ones I have because I have enough frustration from dropping Lego pieces to actively make myself go looking for those darn things. Just sharing something I think is cool. How about that? Have a bricktastic weekend friend!
You wouldn't need a vacuum chamber, you'd just need to wait long enough for the internal pressure to fall back down to ambient pressure. It's not going to form a perfect airtight seal. … Or I guess you could just drill a little hole in one of the bricks to let the air move freely.
While Diatonicdelirium's comment is definitely very correct and I consider it the first piece of the puzzle, I'd also consider the following: The two surfaces of plastic that are engaged in this coupling are actually _not_ perfectly smooth. That ensures a big part of the friction we're seeing (rather than one purely based on Wan-der-Waals forces, which is very weak in sliding motions anyway). So when we overcome the static friction - and then _continue_ rotating (note how it doesn't immediately pop out or shoot out the moment static friction is overcome), we cause the two rough surfaces to rub against each other, causing microvibrations in the plastic. That, I believe, is the key to this mechanic. Vibration propagates through the material in all directions and the coupling uses that energy to settle into the state of least potential energy (least tension/deformation). Which, micromovement after micromovement, eventually pushes it out just enough that the friction of the remaining contact surface is sufficiently low for the elastic forces to pop the piece out.
Usually there is a broader connection than just a stud to anti stud for most bricks and systems. I have had some of my oldest cones and studs fail at their antistud connection. 20+ years of collecting but still.
Well, actually, the space into which a stud is pressed is not always simply a hole to accommodate the stud. Most pieces have a cylindrical extrusion hanging from the roof of the piece which the stud presses against, and on the sides planar extrusions reaching inward to also press against the studs. This is probably to save on plastic, and they figured it worked just as well.
I don't think it's slightly angled, I think it just starts moving somewhat freely on that axis, and because there's a stopper on one side then it naturally moves the other way.
They probably don't use it in set designs as a play feature because it'd be considered an "illegal" technique, causing increased stress on the bricks. It might not seem like much, but the twisting causes friction which will eventually wear down the bricks faster than other activities would.
Actually, I think the shape you're describing does not arise from the pushing-together of the bricks; rather, it's probably a function of the manufacturing process. The bricks are made by injecting plastic into molds. After the bricks harden, they need to be removed from the mold. This would be virtually impossible if any of the voids in the bricks (including gaps between studs) were exactly the same dimensons at the top as they are at the bottom (in other words, if the vertical features were at a perfect right angles to the horizontal features). So in order to facilitate removal from the mold, the vertical features need to be ever so slightly slanted in just the way you describe.
To some minor degree it's been utilized in a manner like the stand on your MOC to make it easy to remove Minecraft characters (eg. Pig, chicken, creeper) in some sets. However, I haven't seen it used for an action-oriented feature.
If you ran a gear to 4 gears hooked up to this mechanism, could you use it to release 4 studs at once? If you can hook it to more studs you can hook it to larger objects that can be dropped off.
Someone must have modeled this in FEM at some point. For sure Lego has. I might look to see if see if I can find the result on youtube. The model would be relatively simple to do in ANSYS depending on how much details you want in your model.
I suspected that the studs are slightly conical-it just made sense that that would be the case. I couldn’t find any definitive evidence though, so I didn’t wanna just assume but I at the very least knew they would deform.
@@crazydog1750 I'd believe it, I know for sure that brick sides are drafted slightly for mold release. The studs are smaller so maybe not needed for mold release but I'd wager getting a sloped geometry dialed in would allow for wider tolerances than 90° angles, and still meet the clutch consistency requirements
I'm curious if rotational torque would better explain this phenomena - as in both circumstances, the rotating motion is applying a torque on a piece that is otherwise incapable of rotating. For the Maruader, the hatch is connected to the roof, and in the example build, the standard brick is stuck in place by the guard supports around it. Very very cool video non-the-less, just another Physics undergrad student observing this cool phenomenon
I don't think so. I can see where your mind went with that, since your r x F torque vector will be perpendicular to the plane of rotation, but the problem is there's nowhere for a force to push within the plane of rotation. Think of a screw-they can have a torque in a material because the threads are not parallel with the plane of rotation. Since they're slightly angled, the force (specifically the normal force) pushing on the threads can push in a direction both parallel to the plane and tangential to the axis of rotation. In the LEGO brick, the normal force vectors aren't parallel to the plane, sure, but they're also not tangential. If you take just the component of the vector within the plane where the rotation takes place, it's pointing directly at the axis of rotation. In other words, theta = 0, and so your F•r•sin(theta) = 0. I hope that made sense. You said you were a physics undergrad so I felt like I could use some nerdier vocabulary, lol.
@@crazydog1750 it is still three years before the video was recorded. In the future I hope that people will be smart enough to realize that, and also smart enough to do basic math. ...wait...what's that? They won't be? Huh? Well that sucks.
Game. Definitely game. Make a batman multiverse game, switching between multiple eras of batman, like that video. Maybe introduce the whole Dark Knights Metal evil batman as well.
Sadly it's bad for parts and new lego plastic. I launched spinner from set 70685 few times on day 1 and minifig legs already lost their clutch power so I can't launch spinner at high speeds(when it's opens) because that twist friction wore off plastic.
I have a question: Did your rig allow air to escape the attachment point or not? I couldn't tell. It looks airtight. I believe that when a single stud is pressed into a single attachment point, air is compressed inside, and that air can push out the stud. I have seen small pieces with a single attachment point pop off sideways, all on their own, without being touched.
I don’t think that the air pressure alone would be enough to do anything. If you’ve got pieces falling off the side, I’d imagine that it’s more due to loss of clutch power. Yeah, air pressure’s gonna help, but it won’t be everything.
I hope my entry for week 46 of the MOC contest went through to your e-mail inbox, would be a shame to miss out again now that I'm finally back from summer break
wouldn't it be considered an illegal build technique? I mean repeat that once or twice - no big deal, but using micromotor or other automation to make this a gameplay feature can possibly lead to studs' surface wearout, thus leading to poor connection.
Could it also be angular momentum? I have no doubt that the studs are slightly conical. But just like when you hang a bicycle wheel from a rope and spin it, it has angular momentum and stays upright instead of falling. Check out the video below if you’re curious. Maybe when you spin the top brick it creates some sort of angular momentum that will push the stud off. Did you try spinning the brick the opposite direction to see if it cinches on harder? ua-cam.com/video/8H98BgRzpOM/v-deo.html
No, angular momentum has nothing to do with any of it. The first and biggest clue is the fact that the brick (or panel or whatever you’re “launching”) are pushed off completely perpendicular to your plane of rotation (and yes, you can spin the box either way and it’ll still work). I cannot think of any example where a change in angular momentum exerts any kind of force completely perpendicular to its rotational plane. Glad your mind is thinking of these things, though-even if they are completely unrelated. That shows enthusiasm and that’s probably the most important thing when it comes to science.
There are two separate phenomena occurring in this video. One you describe. Seems to make sense. The other you show but do not tell. The LEGO writing sticking up from the top of the adjacent studs forces the joint to pop when the block is twisted and its edges come in contact with the studs. I would have stopped there.No further interest. At 65 I'm over LEGO now and so was my boy when Minecraft came out. Star wars was never a thing for me.
This was my thoughts exactly! I kept thinking "Yes yes yes. We all know this. Move on to the *actual* content! It was finally at the last mminute or 2 that he actually got to the "new" idea....
I think you're actually missing the most important effect of the twist. See, once the twist begins and we enter the dynamic friction regime, the friction force can only act opposite the direction of motion.
Since you're rotating the stud, then all of the friction acts about the circumference of the stud and none of it acts along the axis of the stud - you know, the direction that actually matters.
The only way an axial friction force can be generated in this regime is when the stud begins to move out of the hole, but it will only be a small portion of the friction vector, and of course at that point the stud has already moved, so it coming undone is inevitable.
I know a lot about this from the racing world, where people talk about the grip circle for tyres, and for instance you can manipulate the angle of force generated by sliding tyres just by changing their speed with the throttle, which is important for car control.
That actually makes a lot of sense… I wasn’t even thinking about the fact most of the friction vector would be horizontal. I guess that makes LEGO even stronger if barely any of the kinetic friction is resisting the motion but it still falls out as slowly as it does-that’s actually totally wild.
Good catch, I wish I’d considered this before posting the video.
@@crazydog1750 No worries! Thanks for the pin. I'm subbed now so if you make a follow up I'll definitely watch :)
@@excrubulent But of course. When someone corrects what is clearly an overt mistake, I pin it. I just wish that I could have multiple pins because there have been a couple mistakes that were corrected by commenters… 😭😭😂
I don't think this is accurate. Motion in one direction doesn't somehow completely nullify friction in an orthogonal direction. If a block sliding along a surface were given a perpendicular shove, you wouldn't expect it to start gliding frictionlessly in that second direction.
@@wfjhDUI I didn't say it was frictionless, I said there is no component of friction in that direction until it begins to move in that direction. There is resistance, but only after movement in that direction has begun.
If you want to set up a test for this using a sliding block, set up an inclined plane and place a block on that plane, then try pushing the block sideways across the plane. It will immediately begin to slide down as well as sideways. You might want to use a round puck shape for the block to eliminate certain effects created by interactions with the pushing object.
The studs are slightly conical for (1) being able to get it out of the mould and (2) for children being able to take them apart without excessive power. The bottom openings are also slightly tapered of (1), but far less than the stud.
I was wondering if that might be the case but I couldn’t find anything about a slight taper. I spent several days looking because I felt like that would make a lot of sense but I found nothing.
@@crazydog1750 "Designing Lego brick and its mould for manufacturing" - Kajal Bhandari
That's called "draft angle." Everything injection molded has it.
@@Crlarl there are some that don't but it requires special consideration when designing the mold
nuh uh
As a current high school physics student who didn’t quite grasp the intricacies of how friction works when we covered that, this genuinely helped me understand it better!
…too bad my exam was yesterday 😔
My first one is a couple months
Obviously professors should be using Lego elements to teach physics.
The bigger issue is that it becomes unreliable with time as the anti-stud wears down. The friction fit you want for the play feature no longer holds, and the set fails. I have 20+ year old legos, cone pieces and studs are particularly prone to this type of failure, which are the same type of connection you would rely on.
To be fair, 20 years would be a pretty good lifetime for most other Lego play features. I doubt flick fire missiles would last that long before getting loose, spring loaded shooters would lose their tension, rubber bands rot and crumble, etc
@Nadiki to think of ot I also have several bionicle joints that have failed and a flicker that has failed as well. Though the studs have failed just from removal and placement, a play feature would increase that expectation.
Wash them in the laundrymachine in a cloth bag on low. It will reset the stresses on the most outside plastics and give the pieces a couple years second life
@BartJBols Playing devil’s advocate, it’s not a question of the commenter knowing how to address the issue personally, it’s a question of expectations Lego can set for a product they sell. If they were to use this aspect for a product, take for granted that they wouldn’t do it dependent on customers running their pieces through a washing machine.
Some of my 30 year old Lego figurines have floppy legs and spinning shoulder joints. They also have about 100.000 hours of playtime under their belt and I am very honored to pass them up for my son, when he grows old enough to appreciate the figurines automatic bow for the king feature 😂
6:03 the “squeezing” might be too much stress on the bricks, but then again there was the hero factory ball launcher
The studs are squeezed when you put them together anyways-it’s what allows them to have clutch power in the first place.
Just hero factory?
@@-howtomake999 Yeah, Bionicle (AKA the GOATs) had it way before HF.
@@crazydog1750 oh well I only ever got 1 used HF set with the thing
Bionicle*
I love how lego enjoyers keep figuring out how well designed lego is.
This could be really cool with gears to extend the rotation out. A row of gears could cause one twist to release several bombs, drones, or drop pods at once!
That would be seriously awesome.
If you control the rotation with levers that are raked by another piece you could make them drop in quick succession, like a carpet bombing manoeuvre. If you really want to show off you could even run your aircraft along zip lines with a piece in the middle to rake the levers, so it all happens automatically. Maybe even put tissue paper parachutes on the payloads for a realistic package drop.
Also an array of small gears in sync would be able to hold and drop larger weights. On the end of an articulated arm it would look like one of those scrap metal cranes that hold metal with an electromagnet.
Imagine having a rig similar to your test rig, but say, times 10, and putting it on the bottom of a plane or something! You could drop a whole load of payloads form the bottom of the plane simply by spinning a component at the top and moving that rotational force with a set of gears inside the build! pretty cool discovery
I am thouroughly impressed with your nerdiness.
😆
Lego studs have a 0.5 deg draft angle to allow ejection from the mold.
You are also missing that the total friction force is constant. When pulling directly apart, the friction is fully fighting the pull. When twisting, that force is applied against the twisting, so there is less available to fight the pulling. Think of this like how the rear tires of a car can slip sideways if the car is rear wheel drive and someone jams on the accelerator.
As someone who tends to make small intricate builds, I am very well aware of this "feature." Its pretty annoying for single stud connections
This is just genius, I need this in a set ASAP!
Ive noticed it for years. Its a real issue when trying to make stud connection turrets for micro scale. Same thing happens with other objects too.
The clutch power could be increased to hold larger assemblies on, by making a 2x2 grid of axle holes and linking them with 8t spur gears. Add 1x1 cones to the ends of the axles to get single stud ends that each rotate with the axles. They will rotate in opposing directions but that won't affect the releasing function at all
That’s actually a really cool design idea.
I find this interesting but I think this has more to do with Lego having looser tolerances in their plastic these days. If you do this same experiment with pre-'00 bricks which have considerably better clutch power, they more often stay attached, even when rotated! (you may also observe how much more weight they can support in a horizontal application when using classic 1x1 snot bricks vs any modern counterpart) I doubt Lego will try to highlight this as a feature in sets since it brings so much attention to the shift in plastic quality/clutch strength. One place this effect was used nicely in Lego sets is the round stud-shooter that are included in many modern sets. They rely on the loose connecting and being slightly twisted in order to pop-off.
You explained this well enough that once you went back to the diagram of the bricks after mentioning the differences between static and kinetic friction I immediately understood what was happening without you having to explain it. This is really neat! Thank you for sharing!
I’m so glad. I’m always worried I’ll end up not being thorough enough or so thorough that it get confusing. 😂
Bro went isaac newton on this
Bro ate dinner
This could be cool for some play features. I'm a big fan of how creative play features in lego sets can get. We'll be watching your career with great interest.
I’ve noticed this but didn’t think anything of it
Well, clearly, I did. I thought of it A LOT. 😂😂
lol I'm imagining someone saying this same thing but instead to Isaac Newton about gravity
guys don't eat lego it hurts
Aww but it tastes so good!
@@LSW-GUY trust me, you need to resist the urge. you don't want this
@@chlumbis choomp* crunch* crunch*
@@LSW-GUY you made your bed now you need to sleep in it
@@chlumbis i mean it is 12:39 am in my time zone
This makes sense. Although it brings back memories of how stressful all those physics classes were, lol. We can add that dynamic friction causes tiny vibrations in this case, which can cause the contacting surfaces to separate slightly over and over as you spin
Based on the fact you called them “stressful” and not “the coolest thing ever” I’m guessing you were more of an engineering guy than physics itself. 😆😂
@@crazydog1750 Ha, yeah. MS in Structural Geology (Studied Magma)
@@geologyjoerocks That’s actually super cool.
@@crazydog1750 it really is! Thanks
Interesting little physics study. Though ya can't overlook the slight bevel on the edge of the studs. That bevel definitely adds to the outward "ejection" force.
I literally found this out last night, I tried it with a lego lever piece.
This must be why twisting a head off is easier than pulling it straight off.
Partly. I also forgot the fact that the friction actually changes direction as well when you rotate it which will have a stronger effect, but yes.
i've been using legos in non conventional connections for as long as I can remember, however in general to something like that I'd have reinforced so that it does not come off (most likely to the physics you describe here).
but some of the other unusual ways i'd connect things-
the flats fit just perfectly between studs so you can enact a directional change in which the studs point.
just connecting to one stud allows you to create a moving joint. altho you will want to reinforce it to keep things from coming apart.
a single point cylinder or dot (basically only a stud on top and connector opening on bottom with as little plastic as possible inbetween), will fit just perfectly in the empty space between 4 studs arranged 2x2.
a single stud will fit into those larger circles on the underside that normally act as walls to keep studs pressed into their usual place (altho with older legos it's a really tight fit).
also legomen legs make for some good joint mechanics if you are short of real dedicated lego joints. as well as a decent method to change stud direction as well.
with these sort of tricks i used to make mechas of all sorts with just the plain and simple legos. usually bipedal.
Most underrated LEGO StarWars you tuber
more people should watch and take part in his MOC contests! those are so fun
I would suggest a further experiment. Find a block/plate with a hole through the block where the anti-stud is, (Some technic blocks come to mind.) This would also remove the possibility that trapped pressurised air in the anti-stud has any effect. If it drops off the same speed, no effect. If it takes longer, air pressure is normally assisting.
Same with a mouth piece for a brass instrument. If i just push in my trumpet mouth piece straight in and try to pull it straight out: 1. doesn't seat well 2. is annoying to pull out. VS if you twist it in, and twist it out, it seats well and removes smoothly
I wonder if the air pressure has anything to do with it. The jumper tile has a hollow stud and even though it is tiny, there is a slight increase in air pressure between stud and antistud . Especially the round antistud in the center of the brick. Could you possibly try this inside of a vacuum chamber? Maybe you get a different result, maybe not. It might be exactly the same. With the scientific method, all the margins for error in experiments need notice. Y'know to make sure.
Also there is this six shooter assembly they've been making with a similar effect. My first experience is on the Marvel Rocket mech. A very cool set. Part numbers 77257 and 77258. There's a different principle going obviously. But you will lose the studs loaded into it if you're not very careful twisting it. It's got the little round studs on one end and you spin the center piece which has a tiny point on the cylinder that pops the studs off. I like the little graphic in the instructions reminding you not to shoot your eye out ( ala "Christmas Story" ) with a Minifigure head with an eye closed inside the classic circle with a diagonal line through it. The 'don't do this' sign.
The point has an angle to it that digs under like a brick separator popping it out. I've always liked the assembly but I don't shoot any of the ones I have because I have enough frustration from dropping Lego pieces to actively make myself go looking for those darn things. Just sharing something I think is cool. How about that? Have a bricktastic weekend friend!
You wouldn't need a vacuum chamber, you'd just need to wait long enough for the internal pressure to fall back down to ambient pressure. It's not going to form a perfect airtight seal. … Or I guess you could just drill a little hole in one of the bricks to let the air move freely.
While Diatonicdelirium's comment is definitely very correct and I consider it the first piece of the puzzle, I'd also consider the following:
The two surfaces of plastic that are engaged in this coupling are actually _not_ perfectly smooth.
That ensures a big part of the friction we're seeing (rather than one purely based on Wan-der-Waals forces, which is very weak in sliding motions anyway).
So when we overcome the static friction - and then _continue_ rotating (note how it doesn't immediately pop out or shoot out the moment static friction is overcome), we cause the two rough surfaces to rub against each other, causing microvibrations in the plastic.
That, I believe, is the key to this mechanic. Vibration propagates through the material in all directions and the coupling uses that energy to settle into the state of least potential energy (least tension/deformation). Which, micromovement after micromovement, eventually pushes it out just enough that the friction of the remaining contact surface is sufficiently low for the elastic forces to pop the piece out.
I like your design for utilizing this. A drop ship with cargo or a rover would be fun.
Tbh… Such a move would likely be a forbidden lego move.
This might rely too much on the durability of the pieces themselves idk
Normal play already relies on the durability of the pieces, the bricks can take it
Usually there is a broader connection than just a stud to anti stud for most bricks and systems. I have had some of my oldest cones and studs fail at their antistud connection. 20+ years of collecting but still.
I think an example better than the coin launcher that would fit the LEGO motif would have been the stud launcher, same applications, same outcomes
No, the process there is entirely different. It’s not being squeezed out from all sides, but rather popped out from the back.
Calling 2021 a long time ago is crazy 💀
With the past three years that I’ve had… it feels like a lifetime ago. 😂
@@crazydog1750said like someone born after 2000 :p
Well, actually, the space into which a stud is pressed is not always simply a hole to accommodate the stud. Most pieces have a cylindrical extrusion hanging from the roof of the piece which the stud presses against, and on the sides planar extrusions reaching inward to also press against the studs. This is probably to save on plastic, and they figured it worked just as well.
Twisting a brick is the best way to remove a 1x1 plate or tile when disassembling a set because of this
I don't think it's slightly angled, I think it just starts moving somewhat freely on that axis, and because there's a stopper on one side then it naturally moves the other way.
They probably don't use it in set designs as a play feature because it'd be considered an "illegal" technique, causing increased stress on the bricks. It might not seem like much, but the twisting causes friction which will eventually wear down the bricks faster than other activities would.
This is cool! Very interesting and very well explained. Just subscribed!!
what I thought It would be: the fact that the bottom things could be a turn point for a brick other than 90 degree angles
Actually, I think the shape you're describing does not arise from the pushing-together of the bricks; rather, it's probably a function of the manufacturing process.
The bricks are made by injecting plastic into molds. After the bricks harden, they need to be removed from the mold. This would be virtually impossible if any of the voids in the bricks (including gaps between studs) were exactly the same dimensons at the top as they are at the bottom (in other words, if the vertical features were at a perfect right angles to the horizontal features). So in order to facilitate removal from the mold, the vertical features need to be ever so slightly slanted in just the way you describe.
Hope this catches some attention for designers
I think lego would consider it illegal. Seems anything illegal is because of excessive wear. And twisting on the stud would cause extra wear
This feels like a video game glitch/intentional code glitch to avoid no clips
Structural ENGR here. The physics checks despite not consideration to stresses
Could be useful in a lego technic crane that uses this mechanism to disengage its grip on certain crates
To some minor degree it's been utilized in a manner like the stand on your MOC to make it easy to remove Minecraft characters (eg. Pig, chicken, creeper) in some sets. However, I haven't seen it used for an action-oriented feature.
There are technic hybrid axels with a stud on the end. That could also be interesting if it works with this feature. Thanks for the video.
4:58 friction is spelled wrong
What? You’ve never heard of friciotn? 😂😂😂
That must be why they’re called “jumper” plates!
😂😂 That's awesome.
Alone the demonstration tool is a thumbs up
maybe ill have to start considering this for mocs, thanks for thr info!
Wow, now I want to build something that uses this technique
If you ran a gear to 4 gears hooked up to this mechanism, could you use it to release 4 studs at once? If you can hook it to more studs you can hook it to larger objects that can be dropped off.
Didn't expect to see HRP-2 today.
i love learning physics from lego vids!
This is actually pretty cool!
Well done, easy to understand.
Someone must have modeled this in FEM at some point. For sure Lego has. I might look to see if see if I can find the result on youtube.
The model would be relatively simple to do in ANSYS depending on how much details you want in your model.
i love all the emoji guys
I suspect draft angle on the studs and tubes is a bigger factor than actual deformation, but essentially the same physics
I suspected that the studs are slightly conical-it just made sense that that would be the case. I couldn’t find any definitive evidence though, so I didn’t wanna just assume but I at the very least knew they would deform.
@@crazydog1750 I'd believe it, I know for sure that brick sides are drafted slightly for mold release. The studs are smaller so maybe not needed for mold release but I'd wager getting a sloped geometry dialed in would allow for wider tolerances than 90° angles, and still meet the clutch consistency requirements
@@crazydog1750 lol I'm reading other comments now that wrote it better than me. Great video btw
@@PopperOfCorn Hey, I understood what you were saying. It’s good to have a few different people independently confirming my suspicions. 😂
I'm curious if rotational torque would better explain this phenomena - as in both circumstances, the rotating motion is applying a torque on a piece that is otherwise incapable of rotating. For the Maruader, the hatch is connected to the roof, and in the example build, the standard brick is stuck in place by the guard supports around it. Very very cool video non-the-less, just another Physics undergrad student observing this cool phenomenon
I don't think so. I can see where your mind went with that, since your r x F torque vector will be perpendicular to the plane of rotation, but the problem is there's nowhere for a force to push within the plane of rotation.
Think of a screw-they can have a torque in a material because the threads are not parallel with the plane of rotation. Since they're slightly angled, the force (specifically the normal force) pushing on the threads can push in a direction both parallel to the plane and tangential to the axis of rotation. In the LEGO brick, the normal force vectors aren't parallel to the plane, sure, but they're also not tangential. If you take just the component of the vector within the plane where the rotation takes place, it's pointing directly at the axis of rotation. In other words, theta = 0, and so your F•r•sin(theta) = 0.
I hope that made sense. You said you were a physics undergrad so I felt like I could use some nerdier vocabulary, lol.
kenetic friction vs static friction
This might be why they don't use those stud plates for turntable pieces like @rrslugger wants them to
Damn, this was a cool video. This channel keeps being great
That is really interesting and I am definitely going to add this to my next MOCS
How competitive is this as a design for an RS NOR latch?
What about the trapped air? Isn't that compressed?
0:01 "A long time ago..." Three years ago to be exact.
🤫 What if someone is watching this in 2025?
@@crazydog1750 it is still three years before the video was recorded. In the future I hope that people will be smart enough to realize that, and also smart enough to do basic math.
...wait...what's that?
They won't be?
Huh? Well that sucks.
Game. Definitely game. Make a batman multiverse game, switching between multiple eras of batman, like that video. Maybe introduce the whole Dark Knights Metal evil batman as well.
Interesting
we’ve rediscovered friction
meulin….
@@flarflecakeshrllo mario
Is there also a very slight amount of compressed air in there too? Only a very small amount.
Probably, but I think the bulk of the force comes from the angle.
Yeah this was a pretty cool video, thank you
Square stud shooter./ Jumper stud shooter.
Sadly it's bad for parts and new lego plastic. I launched spinner from set 70685 few times on day 1 and minifig legs already lost their clutch power so I can't launch spinner at high speeds(when it's opens) because that twist friction wore off plastic.
I'm doin' all right
Gettin' good grades
Future's so bright
Gotta wear shades
Lego minifigs live in a world made of their own flesh.
The emojis are so wholesome I love the 2007 PowerPoint aesthetic this has
I have a question: Did your rig allow air to escape the attachment point or not? I couldn't tell. It looks airtight. I believe that when a single stud is pressed into a single attachment point, air is compressed inside, and that air can push out the stud. I have seen small pieces with a single attachment point pop off sideways, all on their own, without being touched.
I don’t think that the air pressure alone would be enough to do anything. If you’ve got pieces falling off the side, I’d imagine that it’s more due to loss of clutch power. Yeah, air pressure’s gonna help, but it won’t be everything.
Or you could have just said "cause magic" and that explanation would have worked fine too.
AWESOME DUDE!
That’s really cool
Cool breakdown. I appreciate nerdy observations
This is incredibly obvious. How did you not realize this?
I hope my entry for week 46 of the MOC contest went through to your e-mail inbox, would be a shame to miss out again now that I'm finally back from summer break
wouldn't it be considered an illegal build technique? I mean repeat that once or twice - no big deal, but using micromotor or other automation to make this a gameplay feature can possibly lead to studs' surface wearout, thus leading to poor connection.
Could be… but the same thing happens anytime you separate two LEGO pieces, really. It’d just happen faster here.
Could it also be angular momentum? I have no doubt that the studs are slightly conical. But just like when you hang a bicycle wheel from a rope and spin it, it has angular momentum and stays upright instead of falling. Check out the video below if you’re curious. Maybe when you spin the top brick it creates some sort of angular momentum that will push the stud off. Did you try spinning the brick the opposite direction to see if it cinches on harder?
ua-cam.com/video/8H98BgRzpOM/v-deo.html
No, angular momentum has nothing to do with any of it. The first and biggest clue is the fact that the brick (or panel or whatever you’re “launching”) are pushed off completely perpendicular to your plane of rotation (and yes, you can spin the box either way and it’ll still work). I cannot think of any example where a change in angular momentum exerts any kind of force completely perpendicular to its rotational plane.
Glad your mind is thinking of these things, though-even if they are completely unrelated. That shows enthusiasm and that’s probably the most important thing when it comes to science.
This is actually kind of brilliant. You could even make a kind of lock with this mechanism.
Fellow physics student that like lego??!!!!
I’m guessing that the overlap of physics students and LEGO enjoyers is probably quite large. 😆
@@crazydog1750 Physics undergrad, physics graduate student, or physics adjacent major? I am a Physics grad student btw.
@@coocooman I’m just a little physics undergrad right now. 👶
You getting a Master’s or a PhD?
@@crazydog1750 haven't gotten my masters yet, but it is a PHD program where you get your masters along the way.
it always did that (87 kid)
it be a 0.001 / from 90
Sense guys are sometimes called "Studs." Can they call their girlfriend "a Brick"?
There are two separate phenomena occurring in this video.
One you describe. Seems to make sense.
The other you show but do not tell.
The LEGO writing sticking up from the top of the adjacent studs forces the joint to pop when the block is twisted and its edges come in contact with the studs.
I would have stopped there.No further interest.
At 65 I'm over LEGO now and so was my boy when Minecraft came out.
Star wars was never a thing for me.
Not quite-there’s quite a bit of clearance between the studs and the box in the first example. They do not come just to contact at all.
I didn't expect that level of physics in a lego video. Good video. Jesus loves you!
Best of luck with your pursuit of science. It's definitely in your blood.
neat
Brilliant video!
I understand completely. I'm not being sarcastic BTW 😊
I thought it was obvious?????? You guys just learned this?????
This was my thoughts exactly! I kept thinking "Yes yes yes. We all know this. Move on to the *actual* content! It was finally at the last mminute or 2 that he actually got to the "new" idea....