Testing Lego-compatible Axles (max torque, durability, friction, etc)
Lego plastic vs carbon fiber vs aluminium vs stainless steel. Lego-compatible axles tested comprehensively. Enjoy!
0:09 Max torque test
4:15 Durability test
5:56 Friction test 1: car and a slope
6:54 Friction test 2: rotating plate
7:51 Noise test
8:44 Insertion test into Lego parts
9:44 Close-up images
10:21 Weight & density comparison
10:53 Price comparison (Nov 2023)
11:14 RESULTS SUMMARY
Carbon fiber axles are made by CaDA Bricks.
decadastore.com/products/cada-carbon-fiber-axles-jt7001?ref=bec
Aluminium axles are made by Metal Technic Parts a.k.a. Dark Ice Designs. They also make the metal gears and beams that were used in the max torque test bench.
metal-technic-parts.com/collections/axles
Stainless steel axles were originally sold by Brick Machine Shop on BrickLink (obsolete), later cncgear on EBay (obsolete), and now planned to be sold by Prototype Production.
My absolute FAVORITE part of this video is that as it progresses, we get failure data for parts that aren't even suppose to be tested because the tests keep DESTROYING normal lego parts.
"And finally, the steel axle can handle 12 Nm." "12 Nm? "Well, that's where our testing equipment broke..."
@@Magrior made my day lol
This happens in a lot of their videos and I think it's the best part. I don't remember which one it was, but the machine kept getting more and more ridiculous as tests continued.
Part breaks, replace with steel. Test again. Part breaks, replace with steel. Eventually it will become all steel 😂
I come here for the LEGO torture! 😂😉
We’re all carefully watching this video like we’re some executives at Lego, and we’re about to approve the new material for a special Lego set.
I feel like an engineer just by watching the video
Lmfao I feel grossly underdressed
And in my case the special Lego set has to be carefully separated from the regular Lego set so as to not accidentally mix my genuine with non genuine Lego. Its kind of funny because some parts like metal axles and upgraded motors are better than the original, but all the bricks are significantly inferior. I really should just make a tier 1 set with the best of everything.
@@deletdis6173omg u so funny sigma skibidi 😱
What we don’t know is BEC presented this in a boardroom meeting before making this video public
The explosive nature of LEGO, amazing
Long time no see leokim!
holey crap leokimvideo
YOOO ITS THE REDBACK SPIDER GUY!
Leo! Long time no see!
holy crap its leokimvideo
The steel insertion test is what happens if you forget to chamfer your edges after milling. It had edges at the end that were still sharp, and with a few seconds with a file or abrasive could probably be considerably improved.
Would make them much less affordable tho... and they arent cheap as is.
@@dazley8021If they’re expensive then most of that cost is simply mark-up because it’s a niche market. Looking at the steel axles, it looks like the manufacturer bought steel rod in the correct diameter, then used an end mill to cut the grooves. If it was done by hand the cost might be reasonable, but it’s almost certainly done on a CNC, where you could make a change in tooling to an appropriate rounded-edge end mill and get the correct profile without much extra work, making it easier to get parts onto the axle. A nice surface finish might be achieved by putting the axles in a vibratory tumbler.
@@SkigBiggler extruding them with a set of dies that progressively cut it into a cross axle would be much cheaper i bet
@@dazley8021 Initial investment in steel extrusion equipment and the dies would be quite expensive. If you already had the equipment or had someone nearby who could do it for a reasonable price, it’d be a better option. The aluminium axle was clearly extruded, but I think the equipment for that is a lot easier to get and cheaper, cause aluminium extrusions are pretty common, and operate at lower temperatures. Using a CNC setup would be a cheaper investment if the axles aren’t a huge seller, cause you can use it to make all sorts of small parts. If you were really mass producing at a huge scale, extrusion would definitely be the way to go, long term costs would be a lot less I think.
The edges need chamfering all along the shaft too. You could actually hear a bit of a scraping sound in the sound test which is almost certainly those sharp corners slightly scraping the plastic. This likely hurt it in the friction test as well.
Carbon fiber has much higher potential, but the fibers in this axle are just in the axial direction. If there were fibers going diagonally around the center axis, the torque would be much higher. But due to the shape of these axles it might not be practically possible. If you could somehow do a pull test, the carbon fiber axle might be stronger than the steel one. But for torque, the carbon fiber axle is probably not much stronger than the resin used to reinforce the fibers.
Yeah axles are not the appropriate application for carbon fibre. Idk who thought to make them other than selling it to people who think it's a magic buzzword
Also the size, for something like an car's drive shaft carbon fiber make sense, you can use many layers in different directions and an steel drive shaft is heavy.
@@hashbrown777 Nah, the carbon-fibre axles are GREAT for when you need a stiffer longer connection. Lego them self sometimes use long axles to reinforce things like ship masts and there the normal axles are just not good enough and the carbonfibre fits the bill.
@@ABaumstumpf hm, if you're not using them AS axles then maybe, but fibre's strength is in tensile, not deflection, and you might find that using pure binder, whatever resin it is holding the fibres, will be just as strong over lego's stock plastic for holding masts without any carbon over the distances these axles are in length..
I'm not a material engineer, but don't you all forget now that the primary benefit to carbon fiber is not necessarily just the strength, it's the strength-to-weight ratio. It's still a good option for when you need stiff, but lightweight rods, such as in aerospace applications. Tom Stanton has used them a couple times for his lightweight airplanes to go with his compressed air engines.
Well, now this guy has metal beams, metal gears, metal axles and metal connectors. Should we expect a full-metal lego set?
Metal Gear!? It cant be...
@@joseaca1010 the gears were pretty solid if you ask me
Like an erector set?
@@joseaca1010I was thinking of a full-metal alchemist
@@7HEMUFFINMAN were they rising tho
Four billionaires cried out in terror and were suddenly silenced as the carbon fiber started to crackle.
Too soon.
@@theblackwidowerOh? What's the requisite amount of time, then?
@@redbuck1385 Twenty-eight months.
@@theblackwidower Gentlemen, synchronize your death watches.
@@redbuck1385ok sir
That twisted steel axle looks seriously cool, and it probably still works well, I'd love to see it return in a future build, just wherever you can fit it :)
I'd love to have one hanging like a pendant or something.
Not sure how feasible this would be, but would be cool to see this test done with different plastics (mostly thinking about Delrin) and maybe even different metals (like Titanium or something)
Titanium is pretty expensive
delrin is just a brand name of POM, that same plastic Lego axles are already made of, so I doubt you'd see any meaningful difference
The channel probably has enough money to buy it
@@HzachGames and its ac5tually weaker than steal, its just way ligther
i want to see tungsten carbide
Pretty sure the Lego axles had better tolerances, hence the lower friction in the two tests
Nope, not at all. The friction is simply the material. Axles are made from POM and that is a good choice for Lego axles as it is a tough, abbrasion-resistant and self-lubricating material.
@@ABaumstumpf I don't think they're made from Peaces Of Metal /s
@@mo-s- yeah.. still, the material is called POM, or Polyoxymethylen ... bit long for my taste.
what?@@ABaumstumpf
POM refers to a plastic polymer, the name is just an abbreviation.
3:08 I am now convinced that this is how drill bits are made and cannot be persuaded otherwise.
xd
Would have been cool to see the amount of torque each could handle before permanent deformation. Feel like that would be more applicable for actual usage in most cases. Edit: nvm, those values are listed in the graph at 11:16
Yeah for sure. You can kind of look at the numbers going up and when the deformation occurs and estimate for yourself, but indeed I think that would be more practical. Seeing them break is more YT friendly though as breaking shit is better than slightly deforming for the algorithm.
He did that. Look at the last chart
@@yugang4430 Oh, I didn't notice that. Thanks for pointing it out :D
3:35 This is the best lego destructive pop I've ever seen so far...
8 tooth gear:COCA COLA ESPUMA! *everything explodes*
I feel like in the friction test, you should have accounted for the mass of the axles themselves, the steel axle isn't necessarily doing worse because it has more friction, it might be because it's just heavier than the other parts. Great video!
I don't think so, because you if you're gonna use it in an build it's gonna make it more heavy, you can't have equal weight
@@CorsaMaster yeh but you're testing friction here, not overall best subject..
well, trains are so efficiant because the wheels are steel on steel, not steel on plastic. mabye the materials need to be tested on materials of the same type, which also helps with the durability test due to plastic not being able to scratch steel.
In friction test 2, the axle isn't rotating so the mass of the axle is irrelevant.
i think in the first run steel axle performed better due to larger momentum. adding some weight evened it out a bit, so it performed comparably worse.
3:12 The motor- "Time to put on my hollow mask"
Who else wanted to see a titanium rod 🧞♂️
Me
me
This is like Project Farm for Lego, continue this series please.
next up: lego rpg vs real rpg
The twists in the axles were so artistically formed, I could stare at them for ages!
at around 3:20 it sounds like the deku scrub transformation in majora's mask.
When using non-POM axles in general it is advised to use some lubricant. That is the biggest other difference between standard Lego axles and the other materials: POM is self-lubricating.
How does the self lubrication work?
@@DrakoonLP Not a material engineer so - don't really know how it works, i just know it does and is one of the defining characteristics why you would use POM.
The torque test on the aluminium didn't get a fair shake because the grub screws would have created a weak point, which the others didn't have to contend with
Maximum yield strength to torque shear (all he was reporting in the twist test) is only part of the story. The beginning of bending is a more important figure, because ANY deformation is bad for machine reliability.
@@XxxThePsyCheMisTxxX "ANY deformation is bad for machine reliability" That statement is simply not true. Have you ever heard about springs? Their sole purpose is to deform.
@@anteshell Yes but that's elastic deformation, not plastic deformation.
@@Valkhiya exactly. But the claim was specifically about "any" deformation. They even capitalized the word to emphasize it further.
@@anteshell There's being correct, and then there's being pedantic.
4:08 now it is an ✨art piece ✨ 😂
3:14 Link when he sets the Deku Mask on
This comment made my day
Underrated
Do you think you could do a test with different types of gears at some point as well? Would love to see how much more durable the metal ones are in high stress scenarios, and how much of a cost it has on the friction (and maybe if lubricant can give even better performance?)
1:59 steel Axle is just chilling
1:30 I’ve never seen that happen with that part before 😨 Probably because I mostly just use standard Lego parts 😅
Love the experiments! Very thorough job testing all the aspects of each material. I noticed especially the difference in cross-sectional area between the aluminum and steel axles. The aluminum has very rounded edges while the steel has very sharp edges. Id imagine this probably contributed significantly to the insertion tests. I'm curious if you could do one additional test and report back? (you definitely don't have to, just curious) Use a set of calipers to measure the maximum cross-sectional width and see if there is a difference between the aluminum and steel axle due to the chamfers. Clamp down on the axle at 45deg(where the cross section width would be the smallest) and rotate the axle in the calipers to 90deg. I'm curious if the chamfers of the edges make a significant difference in its maximum cross-sectional width?
Well, I'm curious too. :) These numbers I got with a caliper. Hopefully my eyes saw them correctly. maximum diameter: Lego 4.7 mm carbon fiber 4.6 mm aluminium 4.6 mm steel 4.7 mm minimum diameter (axle 45deg): Lego 4.4 mm carbon fiber 4.2 mm aluminium 4.2 mm steel 4.4 mm Looks like the steel axle is thicker and also sharper in the chamfers, compared to aluminium.
@@BrickExperimentChannel Interesting! Not as great a difference as I suspected... Thanks for doing this! I appreciate that you went above and beyond!
as i have said in another comment, trains are efficiant due to low steel on steel friction. mabye you should test materials on there own materials? also, i saw bits of plastic lego after the steel slide on test, so that says the steel took some bits off of the lego bits. thanks for the good video, tho, i would like to see more.@@BrickExperimentChannel
Use a micrometer or a dial indicator, and get variance across samples as well as within each sample :) Also the surface finish on the steel is still quite rough due to milling marks. I wonder how it (and the aluminum) would fare after some scraping/polishing.
yeah, the edges probably had some influence on the insertion. But I would add that the surface finish might influence significantly as well.
0:28 damn the Lego plastic axle transformed into Haribo licorice
8:38 To analyse noise you should record noise values at regular time intervals and find the average value. You can also find the measurement error using the method of least squares.
1:21 every episode of SpongeBob has one shot like this
LOL
8:33 the framing on these tests is beautiful, lining up the axle and the line between wall and table. nicely composed
Lego should make some official steel/aluminum axles
Aluminum is choice. If only the longer torque-carrying axles are aluminum and the rest is regular LEGO, the engineering is only so complicated. Steel is overkill, as it will shred plastic loooong before twisting, where aluminum's excess strength is less, and it is cheaper and lighter. Aluminum axle couplings are also a good idea, guy shreds several in this video!
I love all the different tests you came up with. I would absolutely like to see this concept done with other types of pieces.
1:35 top 10 unexpected turns in whole universe. Number 1:
The machine isn’t testing the axles, the axles are testing the machine 🪑
@@stargazzer9166 fr
The little machine that did the torque test at the beginning was so powerful!!! I can’t believe it was able to twist that steel bar the way it did.
Love that you've brought engineering/testing into the mix. I'm even more impressed with LEGO parts.
Brilliant! Thanks for the shootout and results!
Fascinating, I love the methodical approach and the camera work. Nicely done. Another interesting test might be how sturdiness on length, if a force is acting on the axle as a lever. If somebody already suggested that, sorry for the repetition. I’ve build some sailing ships using axles to stabilize the masts 2x2 round bricks with axle hole. When you brick build sails all axles bend forward due to the weight on one side of the mast. So far I used Lego, carbon fiber and steel axles and all bend differently, my favorite carbon fiber.
Love watching these tests, not sure why. Just a suggestion - in a comparison like the friction test, especially where as you rightly decided it wouldn’t be super interesting to watch at full speed, you could show all four videos at once (each doing a quarter of the screen). Could also do something similar with rolling tests by super imposing the videos. Keep ‘‘em coming!
The steel ones need better tolerances but they will grow or shrink depending on temperature they look very roughly machined too
Shut up and enjoy the video
Every material expands when temperature rises. This is not exclusive to steel. This is just basic physics.
Looks like we need legos made of gold
@@alanESV2 ends up twisting faster than normal lego 😆
Especially the ends. You can see the plastic ones being cast nice and round while the steel one was simply cut at 45 degrees on a lathe.
Basically: Buy LEGO unless you do some extreme stress tests.
It likely doesnt matter because the ranking was the same at the higher load, but having a more consistent release in the car friction test would increase the accuracy and precision of the results. Ideally a mechanical release that doesnt impart any forward or backward momentum would be ideal, such as raising a boom gate with a programmed motor or similarly retracting a bump into the ground. Same with the noise test. Using the rpm method from before would have been better. You do what you did on the previous test to could spin it up to 300, then use a laser to test when it reaches 200 rpm and record the 200rpm volume
Giving us the "3D" view by rotating the axles close up (with lego motors of course) was a really nice touch
The cross-section of the steel axle is noticeably different than the others; I wonder how much of a role that played in the insertion test.
0:40 - that looks kinda cool
Killer vid as per usual! Have you considered using graphite dust to smooth the carbon fiber/metal parts? It'd go a long way to reduce friction/noise. An old trick we had for roller derbys I thought it was fitting
I am learning a lot of these concepts in my engineering courses and its fun to see them built out of lego
I like the inadvertent testing of bricks, gears, and connectors lol
8:48 This is not a very scientific measurement, your time will improve with the number of repetitions because you get better with the number of repetitions and train your muscle memory ;)
Would love to see a similar test comparing the plastic from different decades.
I liked you starting with the thumbnail and then using it, it actually was a cool vibe
A great way to improve the insertion test results is if all three of the non-official lego parts have their edges smoothed alongside the veins being slimmed just the tiniest bit to match the official part properly more closely. Other than that I think a brass one would probably work really well in terms of the friction tests potentially. Or maybe a different metal that doesn't provide much friction in such conditions if any.
Yeah, but that probaly will influence the fit. Maybe polish first, and see how it changes?
the only channel i know that makes lego cars for a job XD
I could watch these kinds of videos all day long. Love it.
That's such a niche type of videos on KZhead and I love it.
4:34 its sounds like a sped up version of a demon being exorcised (sorry just watched the Conjuring lmaooo)
actually true tho
Wow! I had no idea that many were made!
The scale at the end shows an interestingly graduated trend across all the tests. Good work! :-)
Lego axles are able to have lower resistance because of ultra-fine-tuned curvature and notch, something Lego themselves with the digital models can, while axles of other material have imperfections and can only mimic. Metal parts also respond to lubricants much better. I am sure some of us are secretly dreaming of all-metal legos. That won't be the worst idea, I don't think.
I’d settle for metal power train components that interface in a durable way with plastic Lego components so you can make insanely powerful builds that disassemble instantly once you go full power
Oh no! It's... THE KRAGLE! 😱
I wish you tested the torque of plastic deformation. While the carbon fiber and lego axles seemed to have similar ultimate failure torques, the lego stick seemed to show plastic deformation much sooner...
Great observation!!! The beginning of deformation matters more for engineering than the maximum yield. Exceptions are when a system is only designed to run briefly and can be allowed to destroy itself (nitromethane dragster engines, explosives, single-use rocket engines).
that would have been nice, though much harder to test, since you'd have to have a continuous data stream with the torque measurement as well as the rotational displacement.
Isn't this the third row in his summary table at the end?
Wow, congratulations, very detailed
😮 3:42 just as i was praying yhe motors didnt break
5:15 whay is cold
Warm
3:30. Kinda predicted that
very cool video, on the second friction test, how were you insuring that the block was rotating at a consistant speed at the beginning of each test?
I second this question.
I assume the maximum rpm of the motor was reached before release
Good question. I just let the motor run until it doesn't speed up anymore, which I could tell from the sound. Before testing I verified with a laser tachometer that the motor runs at 330 rpm while rotating the plate, both with a plastic axle and a steel axle. The no-load speed of the motor is also 330 rpm, so the friction and air resistance are negligible compared to the power of the motor. The biggest source of error is in my opinion the variance in the motor top speed. It varies maybe 5 or 10 rpm up or down.
@@BrickExperimentChannel ok, very cool!
Why am I just now finding this channel? This is freaking awesomesauce!!
How about shear load strain testing, like seeing how much weight a horizontal axle can handle? The metals would probably win out by a long shot but I'm curious to see how the carbon fiber performs.
for the durability test to make sense you need to make both the axle and the bearing from the same material. otherwise the harder material (in this case the axle) will destroy the bearing
Now think about it, we're only seeing around 12nm here, when you tighten a wheel nut you often use 90nm or more, thats a torque every humam can easily put out, and its enough to destroy a steel rod
Your Lego automation builds are next-level awesome! 🌈👾
It's very interesting. You also have to realize that the reason why LEGO is all plastic is because it's intended to be used by kids. BUT I will counter-point that with Construx actually had metal axles and was ALSO targeted at kids, it just wasn't around that long to have any incidents that I'm aware of (eg injuries from sitting on one.) I think bigger take away here is that Lego probably could sell metal parts with a warning that "metal parts are intended to be used by adults" , as I could see situations where people lose fingers/eyes/scalp by trying experiments without proper protection.
Wait wait wait, isn't the friction test flawed? You didn't account for the additional mass of the metal axles
Yeah but the test in general wasn't great for friction testing. But who cares the second one was reliable
Hold you’re horses don’t forget the metal alloys, tungsten and titanium they may be expensive but we can’t forget them.
Tungsten is a tad bit heavy :D
@@ABaumstumpf and brittle so Boosh, metal explosion!
For the friction test, I'd like to see a comparison after polishing each of the axles with 1000 girt or finer wet sand paper. You get a more life out of the paper when you do it wet, add a tiny bit of soap and it will polish up faster and give a slightly better finish too.
Would be interesting to see a sliding test of various pieces down the length of each axle. Both a test that sees how much time it takes for a machine to move a piece down the length of the axle using a fixed force for each, and a test that determines the minimum force required for a machine to slide the piece down the axle.
they've gotta add some graphene rods
friction test on ramp is unvalid due to higher mass of alu and steel axels so they have more inertia momentum (in basic it's harder to spin heavier axle)
the outting pueces on test is also scientifically invalid (used different pieces likely with different wear, didnt measure the force needed to put pieces on) but i dont think thats the point of the video. its just fun to watch
I love the extremely close zoom on each piece
Idk why but the sound of the noise test with the single beam took me straight back to my FIRST Lego League days
01:15 there you go carbon-boys... only steel is real ,)
Steel is strengthed by carbon, you're also made of carbon. everything has different strengths, using this video as an argument for carbon fiber being weak is like saying that jet-planes are horrible because they can't drive on lamd
Where did you get the steel one?
Great to see you making compares with other brands. Are you going to compare other parts as well? Especially bricks?
I have bought some of the aluminum ones and they work great in high load transfers that use longer distance axles.
4:46 relatable
How and why cold and hot 5:11
energy
I find it interesting in the ramp test when you added more weight the all lost almost exactly 10% of their original distance, except for the carbon fiber which only lost 5%
Would love to have more data points for each test, however this is still entertaining!
00:36 🦅🦅🦅🦅 FREEDOM🇺🇸
What type of carbon fiber? Forged? Prepreg? Laminar? Carbon ≠ Carbon
I asked CaDA about their carbon fiber axles. These were the only details they gave (with permission the share publicly). Tow: 12K 25K Sizing agent: 1.0% Twisted: twisted, no twist Thermal expansion coefficient: -0.45 10(-6)/℃ Specific heat capacity: 0.18 Cal/g.℃ Thermal conductivity: 0.0252 Cal/cm.s. Resistance: 1.6 x10(-3)Ω·cm Sodium and potassium content:
For the friction test the overall weight of the car needs to be the same, the steel goes father probably due to it’s increased mass than less friction. Also surface finish of each shaft is a variable.
You can really see in the supermacro shots that the aluminum part would have been extruded, and the steel part milled out. I think with higher quality machining the steel axle could achieve a really good surface finish which would help with fitment to lego parts as well as to reduce friction.
8:09 what the fuck
EXACTLY the results we ALL expected, but somehow still very interesting to watch.
Challenge: Do you think you could build a camera gimbal ( pan and tilt ) with automation / features similar to what you would get with a typical stepper motor and Arduino/raspberry pi type of set up ( time lapse and motion control abilities for example ). I've always thought Technic lego would be perfect for prototyping such a setup, if not just building a final product that way...
I love the fact that he does experiments I didn't even knew I wanna know about :'D
Coolest test of lego parts I've ever seen.
4:34 that one mosquito that refuses to leave the room
the steel axle being twisted looked amazing, i'd keep that as a decorative thing somewhere
This test shows off exactly the same situation as the mathematical 'How many digit of Pi do you need' question. A workpiece is only as strong as its weakest part. Having carbon, aluminium, steel, or even titanium axles makes no difference if the rest of the thing is made of lego bricks. When making something out of lego bricks, the optimal axle is one made of.... lego. If you are making something out of steel, use steel axles. If you are wondering the answer to the Pi question, it is to use pi to the number of digits of the least accurate variable in the equation. For example, most people have heard the formula are is pi r squared. If the radius to 7 figures, for example 12.34567cm, then you need Pi to 7 figures as well - 3.141593. If the radius is 'about 7 feet', then you only need Pi = 3.