Measuring Monster Magnet's Grade...

The grade of a magnet is important. It tells you how strong the magnetic material used for the magnet is. The higher the grade, the more expensive and powerful the magnet.
However, measuring the grade is not easy. I have successfully tested it on 70x20 mm disc magnets, but what about my largest magnets: the monstrous Ø200x50 and Ø150x100 mm disc magnets? Let's find out!
Spreadsheet for calculations: www.supermagnete.com/faq/flux
Original paper with calculations: www.researchgate.net/publicat...
The F71 Teslameter donated earlier by Lake Shore Cryotronics:
www.lakeshore.com/products/Ga...
200x50 mm and one of the 150x50 mm disc magnets donated earlier by www.magnetportal.de/
My Patreon-page: / brainiac75
More details on the center axis method for grade estimation: • Can I measure the grad...
Unboxing the 200x50 mm: • Unboxing a MONSTER | E...
Using a kitchen scale for ranking magnet strengths: • Measure Magnet Grade w...
Did you miss one of my magnet videos?: / brainiac75
FULL MUSIC CREDITS
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"Hiding Your Reality" Kevin MacLeod (incompetech.com)
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"Long Note Three" Kevin MacLeod (incompetech.com)
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"Lightless Dawn" Kevin MacLeod (incompetech.com)
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"Perspectives" Kevin MacLeod (incompetech.com)
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All music above licensed under Creative Commons: By Attribution 3.0 License
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Mix of two tracks:
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#MagnetGrade #MonsterMagnet #Brainiac75

[@aarongreenfield9038]

Measuring magnets, a field you seem attracted to.

[@the4spaceconstantstetraqua886]

Haha, very funny.

[@misslonewolf04]

Whats up with that cat in your pfp and yes i get the joke

[@aarongreenfield9038]

@@misslonewolf04. It's just one of my cats, his name is Jake.

[@StemLG]

4:00 you got me so good here, AAAAAAAAH!!

[@MariuszChr]

I almost threw my phone to the wall

[@madbstard1]

Same here grrrrrr. My connection is flaky at best and am used to seeing the spinning wheel and thought it had died again lol.

[@GlenHunt]

My computer has a bad capacitor on the video card and I'm running in safe mode. I was totally sure it was about to reboot itself - again.

[@josephgauthier5018]

same lol. my internet is REALLY slow. consistent, but sloooow.

[@thewolfin]

I've had YT fail like this before, where the video buffers but audio keeps going - so this got me, and my jimmies are rustled.

[@h7opolo]

i suggest contacting the magnet manufacturers to inquire about their protocol for quality assurance which should include steps for taking accurate measurements. then you can follow their methods.

[@brainiac75]

I am pretty sure they use a fluxmeter. It measures all of the magnetic field from the magnet in stead of just on a single, small spot like a gaussmeter. Fluxmeters are just a little out of my league... for now... Thanks for watching!

[@h7opolo]

@@brainiac75 oh word. you'll get there. my pleasure.

[@n9103]

@@brainiac75 Assuming the magnet is otherwise symmetrical, could you measure the magnets from many spots around the circumference and determine the magnetic center based on that? I'm not familiar with FEMM, but could you instead conduct many measurements and let it tell you the grade instead (reverse the equation)?

[@ekstrapolatoraproksymujacy412]

@@n9103 it's not where problem is, problem is that magnetic field shape is different than idealised theretical, probably due to how magnet was magnetized

[@johncage5368]

@@brainiac75 Probably give the physics department of your closest university a call. I assume they would let you come over and help you measure that object of undetermined quality.

[@akshatsharma1]

Wow, you have been doing KZbin for more than ten years and still so underated

[@turji]

It's many good smal channel out here, they are usually the best aswell.

[@brainiac75]

Yep, first video uploaded back in March 2009. 12 years ago... feeling a little old thinking about it. More than a decade! But I have only uploaded monthly for the last 3 years after going from full time to part time at my day job to find more time for making videos. Hope to hit 1 million subscribers before I get too old to make videos x) Thanks for watching!

[@pvic6959]

i agree. but unfortunately his videos take a lot of time and effort so like he said in a comment, he posts monthly. youtube incentivizes to post at least weekly. so i but thats the reason he doesnt get as recommended as we would hope. but i _always_ tell people about this channel if I think theyd like the content. i gotta spread the knowledge of this amazing channel

[@zlunazelena4080]

@@brainiac75 however i need to say than even than there are youtubers that are making more videos, i would say your videos are not that often but they are very good quality

[@akshatsharma1]

@@brainiac75 Thanks for replying!

[@mcxhalo]

3:56 you made me look over to my router instantly lol

[@jaakkojaskari6671]

That grade estimation animation "loading" completely froze my brain for 1,5 seconds. You sir, are now officially the best pranker in my books. I've seen this method used before, but you're the first one that completely fooled me. Rick Astley step aside! Got to love your channel.

[@jaakkojaskari6671]

Subscribed almost as soon as I heard about the channel :) and I don't usually subscribe.

[@brucewrigleysgumchewz4667]

Haha. Yeah. As soon as I seen the loading circle, I thought the KZbin video was having trouble loading. Good one 😅

[@randomcatdude]

only reason that it didn't fool me is because its FPS was too low, so it wasn't smooth like the real buffering would've been

[@Tacdude]

Hi Brainiac, glad to see you're doing so well after all these years on youtube.

[@brainiac75]

Thanks TacDude. There are good and bad times on this platform, but generally my channel is doing alright over time. Maybe mostly because I am persistent ;) Thanks for watching!

[@derdotte]

So i have just gone through the calculations myself (i study physics). Well their approach isnt wrong thats what i can say at first but they assume that a magnet is made up of very small dipoles, something that seems right when you consider the microscopic levels of solid matter physics however gets really complicated when there are multiples working together (multipole expansion is a pain to do right). Their biggest issue is that they do not use the actual method of taking the rotation of the vector potential for the magnetic flux density. Instead they use what we call a series expansion using legrende polynominals. I believe the errors in the calculations using this alternative method comes from all those "alternatives". The vector potential is a bit annoying to handle though, so its understandable that they want a different approach. The second version numerically solves the magnet distribution for an evenly distributed magnetisation. Thats sadly not something that always happens. It would be better to ask how the people who measured it at N45 measured it then going through lots of papers (and quite profound math and physics).

[@brainiac75]

Thanks for the detailed input! My math is not on a level where I could figure that out... But I guess it makes sense that the assumptions made in the perfect, theoretical world are worse, the bigger the magnet is in real life. I will experiment more with FEMM to see how well it holds up for smaller magnets.

[@derdotte]

@@brainiac75 yeah the size is probably the biggest issue here. I am no expert in this though, i just know the basics. Its understandable that not everyone can do this math, its not hard but complicated without all the prep knowledge.

[@yoavnavott]

I think you meant Legendre polynomials, haha

[@derdotte]

@@yoavnavott yes, i must have missed that when correcting most of the mistakes prior to sending. Happens

[@106640guy]

Maybe your magnets arent evenly magnetized with weaker spots throughout them? if thats even a thing

[@brainiac75]

Yep, spot measurements will not tell you all about the overall strength of the magnet. No magnets are perfectly magnetized throughout the whole magnet. But the quite large differences between the poles on some magnets in the video is most likely due to me (ab)using them through many years. For example forcing two equal poles on magnets of different sizes can slightly demagnetize spots on the larger magnet's pole. Supermagnetman has a video on it, but I can't remember which one. Thanks for watching!

[@matchesburn]

@@brainiac75 Have you examined any of the larger magnets with magnetic viewing film to see if there's any anomalies with the magnetic fields?

[@whatelseison8970]

@106640guy This was my thinking too and it seems that possibility had not escaped our brainiac :). It's certainly something I'd be checking too if I'd spent all that money on magnets and gauss meters. @@matchesburn That stuff is awesome. Especially the kind that are full color rather than just shades of green or whatever.

[@Kapalek84]

N grade of neodymium magnet is based on the BH max point on BH graph. I recommend checking out info on KJ magnetics website! That is one of the best sources of info about magnets I could find on the web. I think you can use some iron cube of 1cm x 1cm x 1cm wrap it in a cloth attach to hook scale and compare how many kg force you achieve to detach that cube from the surface on each magnet center. This would allow to compare them all (using magnetometer probe is also ok but the probe might not take the mag field line angles into account). The amount of lines that will be focused on the cube will be proportional to the pull force so you would not have to worry about the spread of the lines. Magnet that achieves highest pull force has caused the biggest quantity of lines to accumulate in the cubes volume) that would indicate that it produces highest field density B in unit volume of iron and that is more or less what the grade is about :)

[@erdmannelchen8829]

You got me on 3:58, thought it was my crappy internet again..

[@herpingscienceandmore8506]

Been watching your channel for many years now and I love it. Keep up the good work.

[@brainiac75]

Glad you like it. Thanks for watching. Much more to come!

[@turji]

Same

[@william21186]

I was waiting for another one of your videos.... So glad you are still posting on KZbin 👍

[@deathrow166]

Damn! You got me at 3:58 ! I hope i`m not the only one who push the refresh button !!

[@biggie_kellogs7919]

incredible how much content you can create just on magnets, fascinating stuff

[@notstrawreally]

This channel made me get more intrest on magnets..

[@brainiac75]

Glad to hear. Magnets and especially what they can do is fascinating and essential to our daily life. Thanks for watching!

[@maulaucraw1209]

Thank YOU FOR THE amazing content! i feel like i've been waiting for this video without realizing it exactly.

[@MemeReviewer]

I am very glad you are still making good videos, and not outsourcing to clickbait, cannot imagine you doing clickbait.

[@kendokaaa]

3:59 you had me there for a second

[@paranoiia8]

It's big chunky magnet... That's the grade we all need to know 😅

[@techalyzer]

Big chungus.

[@techalyzer]

@@satisfyingitems3118 no

[@Gunbudder]

i love this channel. all the sweet toys and tools that i can't afford to buy for myself. you even do the same experiments i would do

[@kendesasiahaan6181]

3:59 really got me

[@brainiac75]

Sorry x) I thought about pausing for even longer before speaking up, but that would only be funny to me. Thanks for watching!

[@binarywizard69420]

lol i watched in 144p and the buffering animation did trickl me XD.

[@Time4Technology]

It fooled me at 720p...

[@brainiac75]

Got ya x) 144p sure hides the minor flaws in the video. Thanks for watching!

[@bornach]

@Ionic777 Imagine the confusion if he forgot to disable midroll ads and one started playing during the buffering sequence

[@MuhammadWafadar-HussainIbrahim]

I was on 4k lol

[@modmodq3784]

I miss your videos thank you so much for the videos!

[@danf6975]

Another absolutely amazing video

[@robertpepperwolfe7256]

4:00 you legit got me for a second there. my internets bad so lagging videos is common XD

[@user-hn4nx1lh4s]

They are grade "Monster"

[@AluminumOxide]

I love how the video starts with a 'hello' from the measuing scale, followed by your sweet Danish voice! (BTW at 0:09 the kitchen scale said 'Err" LOL)

[@sherrymaloner8843]

Seeing a new vid from you literally made my day ❤️

[@DemetriusCoutinho]

i stared at my modem saying "really? righ now?"

[@bright_lego]

Congratulations for getting 2/3rds the way to 1M subscribers!

[@jabr991]

Solid video 🤙

[@Jesus_paid_it_all]

I love your videos. Your easy to understand yet scientific approach is better than any other science videos. I look forward to your videos! Just know that your work does not go unnoticed ! I always learn from your videos. Also, is a 33lb magnet strong?

[@abdullaalzayani6018]

Try modeling the magnet in FEMM vertically and check the value at the centre

[@Porglit]

Intro: "let's see what the grade of the large magnets is" Conclusion: "no clue" That wasn't what I was expecting, but I'm happier having watch this video

[@squishvr174]

everytime i will hear "dont let them bite ya" about neodymium magnets i will always think of the multiple times i cut myself with buzz magnets

[@erikisberg3886]

Great content, subscribed. Very interesting method. I have been using the FEMM software for a long time, amazing free software.

[@Satiricboi]

I love your acent

[@brainiac75]

Glad to hear. Got so many negative comments on my accent back in the days. It may have soften up a little since, but still easily recognizable as a Danish accent. Thanks for watching!

[@Satiricboi]

@@brainiac75 im from argentina and not have any problem with the acent

[@PrivateLZG]

Glad the magnets are here once again ;)

[@RomanoPRODUCTION]

I was about to cry about N33. But I will wait more to unleash the gates of tears

[@Sofia-qn6fs]

So perfect I am a big fan of science and your videos are the best 😉

[@johnspence2466]

Love your videos my son and I have watched every episode

[@brucewrigleysgumchewz4667]

I love neodymium magnets. Can't beat the strength of these things. They are fun to use for experiments with copper wire and an electrical current. Beats the hell out of those crappy ceramic/ferrite donut magnets. Only thing I hate about neodymium magnets is the super low curie temp. It doesn't take a whole lot of heat to turn your neodymium mag into a paperweight.

[@morgellon9449]

I thought this was going to be a video about the band Monster Magnet at first, lol. They were pretty good. I also like magnets-- more than I like the band Monster Magnet, in fact. Bought some ferrofluid recently. Going to make a ferrocell.

[@dimitar4y]

that femm program seems to show the "issue" with measuring from the center. the strength is relative to the distance between the two fields. the center of the magnet is incapacitated by its surrounding so you get a weaker measurement. Sooo that's why pro magnets like magnet chucks or linear steppers make the distance between n-s short as possible by stacking them with alternating poles..?

[@chimera5523]

I'm probable wrong but i think i found the issue it's not the calculation but the gauss probe. It works with the 70x20mm magnet because it covers a sufficient circumference of the magnet. But when used with the 200x50mm magnet the circumference of the probe is proportionally reduced. reducing the area of interaction between the magnet and probe in the vertical access. The reason i think this is the cause is when you measure the horizontal side of the magnet the gauss probe has to a smaller area 50mm vs 200mm witch gave a higher reading.

[@Swidle]

I feel attracted to these magnets

[@BRUXXUS]

I think it could be interesting to measure in a grid pattern across the poles and plot them into graphic. Sort of a topological map of field (flux?) densities. Maybe like 3-4 rings of measurement spots, I don't know... maybe that wouldn't tell us much, but it's something I'd do if I had all that equipment. :P

[@FabriDragon]

I love your videos! If you suspended one of your large magnets by a string, would it eventually rotate and line up with earth’s poles? Like a ridiculously large compass?

[@kyledavidson8712]

The algorithm brought me here. Didn't watch the video. Just wanted to say MONSTER MAGNET RULES \m/

[@r3struction]

The biggest collection of unipolar magnets!

[@ClayLake]

Could it be local variations in the magnetic field's strength leading to the overall grade discrepancies you are seeing? I would guess this may be caused by moments of all the cells in the magnet not quite matching up right. Try measuring the magnetic field along an array of points on entire surface of the magnet. Then fit the readings to the model and back calculate the grade.

[@Ethan.YT.]

First time a fake buffer got me

[@rysea9855]

3:58 Can't believe this got me lmao

[@seanvinsick5271]

Try using Thales theorem to find the center. You can do it with a square and a straight edge.

[@avi8aviate]

Maybe you could try averaging your measurements of the magnets from the top and side. No telling if it'll work, but I think it's worth a try.

[@boogrs55]

quality versus quantity this is definitely quality

[@ehsnils]

This is a quite interesting result. But with a magnet this large the effect of the magnetic field for the surrounding area outside the sensor is also a factor that I think negates the ability for the sensor to measure. Similar to electric fields.

[@pratikpurandare]

Sir, method used in FEMM is perfect. FEMM is verry accurate free software. you can take readings in 2-3 spots to crosscheck and find the grade.

[@Quickened1]

I'm not even sure how a gauss meter works, nor what the sensor itself is made of, but perhaps a larger diameter sensor probe is required for larger diameter magnets to get an accurate reading? What is the probe made of?

[@fluteplayerify]

Perhaps you could measure the total flux by connecting a loop of wire that is just larger than the magnet to an oscilloscope. If you put the oscilloscope into integrating mode (or save the wave form out to a computer) and move the loop from far away to around the center of the magnet, you should be able to calculate the total flux via faraday's law

[@brainiac75]

Bingo. I believe that's how fluxmeters work, and they are the right choice for measuring grade. I just can't afford one and I'm not sure I would be able to calibrate my own... Thanks for watching!

[@bemusedindian8571]

Could you check how perfect are the planes on your magnet? Both the flat and curved surfaces?

[@slicedFlixy]

Hey brainiac, I've been watching for a year now, and only now I find out you're danish. Hello to a fellow dane. Keep up the good work bro Ik tænk på at din accent er dansk, den er perfekt

[@brainiac75]

Well, greetings back fellow Dane. I am from Jylland - as danish as it gets x) Thanks for still watching! Much more to come. Jeg er ikke ked af min accent - men har godt nok hørt meget skidt om den her på nettet ;)

[@MuhammadWafadar-HussainIbrahim]

@@brainiac75 Hmm google be like: I'm not sorry about my accent - but have probably heard a lot of bad about it here on the net It could be: I'm sorry about my accent - but I have heard a lot of bad news about it here on the internet The meaning of the words remain a mystry

[@doubledarefan]

What are the chances of the variations in strength being caused by variations in the magnet's composition? You know, the ingredients not being thoroughly mixed during manufacture. Or bits of foreign matter mixed in?

[@deltacx1059]

Maybe bigger magnets have field lines farther from the center so the reading is off? Just a guess

[@cyb3rk3v]

If you built a rig to force two like poles of strong magnets together, what would the effect be? I heard that electrical arcs can be created. I’ve always wondered if that’s true.

[@glenngriffon8032]

I think it'd be neat to see the magnetic fields of these monster magnets with iron filings. The field is probably massive though so you'd probably need to set the magnet into a cavity in a large piece of wood and lay out a really large sheet of paper on top of that and sprinkle the filings on that. Still, I think it would be neat to see the fields.

[@grannyweatherwax9666]

That sounds like a really good idea!

[@TheWanderer1000000]

3:58 Nice one.

[@aceathor]

Can you produce more power (electricity) if rotating more powerfull magnets than if you have more magnets less powerfull ? Sorry if bad English, French.

[@pewpew4545]

If I had to guess I imagine the grade will be a measure of density of magnetic strength per metre cubed, so the parts of the magnet on the far side from the metre aren't pulling as hard?

[@Jtretta]

I would not be surprised if makers of neodymium magnets that physically large have a methodology of averaging the measurements of many testing spots together. It makes sense, in my head at least, that a combination of geometric distortion of the field from magnet shape as well as material variation throughout the magnet would make generalized, single point classification techniques highly inaccurate and undesirable.

[@electrofan7180]

Please can you measure magnets of what grade are used in HDDs?

[@spacedaway]

Maybe the magnet has lost its magnetism over time?

[@djsmileyoflasvegas]

Ive been a subscriber for along time..im really interested in seeing how the big magnets repulse each other cuz with little magnets its cool i really want to see how far they repluse each other and the strength if thats possible to do like in a big clear acrylic thick tube see if they dont try to flip and break it..lol

[@brainiac75]

Hi. You are not the first to suggest a video on repulsion between large magnets. It is an interesting subject, and I probably will make a video on it eventually. Repelling magnets are just one of the most unsafe scenarios. My biggest 'oopsie' was with 70x20 mm magnets repelling each other until one decided to flip around... Thanks for still watching!

[@djsmileyoflasvegas]

@@brainiac75 it is very scary to think of those flipping and exploding even in a thick circluar tube but thanks for all the great videos i hope you can find a safe way to do that cant wait to watch it someday👍

[@zlunazelena4080]

@@brainiac75 especially disc shaped ones are dificult to keep trapped even in a pipe

[@Sucukmaster64]

Its sick

[@duke.q8379]

Seems like the advertised N grade is an average of Center of Pole and Side. Perhaps as a commercial protection.

[@freekingawwsome]

@Brainiac 75 it's okay too prove the disprove correct for our axsis changes

[@hobbychannel951]

You got ripped off! Crooked magnet companies. :)

[@marsrocket]

Maybe more of a limitation of the measuring devices?

[@tf5658]

you got me Jebaited

[@Noedell]

Make a Biostabil necklace out of this magnet.

[@ajc1476]

How do the manufacturers calculate the grade in the first place? Maybe you can do something similar

[@aureliocoeto765]

How do you store your monster magnet?

[@roboneal]

When the tech guys come to measure our magnets (used to hold up 20ton molds) they always put a 1 inch steal plate in front of it and measures in between mag and plate from four sides not the center. Wonder how this changes field lines and strength.

[@FalcoGer]

Maybe the polarity is skewed? Maybe the poles aren't right in the center of the disk?

[@bdtilesdesigner7516]

Good

[@graealex]

I can report that I now have the same kitchen scale at home.

[@brainiac75]

Congrats :) It is a nice scale. Measuring up to 15 kg in 1 g increments is a luxury. Thanks for watching!

[@graealex]

@@brainiac75 Thank you for your videos!

[@_GhostMiner]

*3:58** I really thought the video froze until i looked the the timeline which was grey* 🤔

[@Qyonek]

Maybe you could map strength of magnetic field of your big magnets? To check of field is uniformly distributed

[@brainiac75]

I have partly mapped the field of the biggest ones, in this video: kzbin.info/www/bejne/haWomJd-mM-mis0 I was surprised to see how many of the magnets have different strengths on their two pole centers. A subject I may to have dig deeper into. Thanks for watching!

[@dimitar4y]

i feel like the north pole is... making the gauss meter act up. The north pole gives low reading falsely, and it drags down the south pole harder and harder as it "penetrates" through the magnet?

[@ItsBBP]

Is the grade a calculated average from multiple measurements? that may make sense when you are getting readings above and below expected, May be worth asking the manufacturer how they measured the grade so you can confirm using a similar method.

[@diogor420]

4k!!! Niceee!!!

[@tomsmith4542]

nice

[@Qoow8e1deDgikQ9m3ZG]

the claimed value is always an estimated value calculated by program. I think the manufacturer measure the magnet strength at different points, and using a mysterious software to calculate the estimated MAXIMUM value of the magnet strength. em .... for the different pole have different values, is that affected by the earth magnet?

[@chrimony]

I'm shocked you haven't used magnetic film on these magnets yet. Check out this video for an alternative take on magnets: watch?v=9sUP_iL6NIU

[@ProtruckR]

Your Not wrong ! The EARTH IS HAVING POLE SHIFT.

[@jakub3851]

0:01 I have the exact same one here in Milan Italy

[@Purple431]

You make excellent videos, im giving you support by subscribing and liking but good none the less. ⚡

[@Purple431]

Love from THE UK 🇬🇧

[@brainiac75]

Thank you very much, TCG. Greetings back from Denmark. I am fascinated by tesla coils and really need to get/build one and make videos about them. Awesome stuff.

[@Purple431]

Lol its a little shocking ⚡

[@ryanwinklevoss]

Took me until now to realise the background music is from kerbal space program.

[@general_prodigy]

Why do you use gauss when you can use Tesla as the unit for magnetic flux(