The Science Of Flatness

Flatness is an often misrepresented property of our own intuition. Many of the objects we consider flat, pale in comparison to surfaces manufactured to actually be flat. It's also a property that our industrialized world relies on to function.
While most of us experience flatness as part of aesthetics and ergonomics, flatness in manufacturing is a critical property of positioning, mating and sealing parts together. The high pressures produced by combustion are contained by two mating flat surfaces aided by a gasket.
Let's look at a sheet of float glass. The floating process self levels the glass, giving it a relatively flat, uniform thickness.
Let's say a manufacturer's specification calls for a 3mm thick sheet of glass. For a sheet to pass a quality check, its thickness is sampled at various points along its length and as long as it is 3mm thick, plus or minus a specified tolerance, the sheet passes.
But what if during the process of moving the floating ribbon of molten glass a subtle disturbance is introduced to the molten metal. Let's say this disturbance imparts a 0.25 mm wave-like undulation throughout the entire ribbon. Now to eye the cut sheets would appear flat and they would pass the quality check for thickness, but the surface of that sheets of glass is far from flat.
Flatness isn’t derived from how closely a part matches its specified dimension. It is a property completely independent of the part’s gross shape.
If we take a surface and sandwich it between two imaginary parallel planes. The gap between the planes that encompasses the surface is known as a tolerance zone. The smaller this distance the flatter the specification.
On parts that do explicitly define flatness the method of both measuring and producing flatness is determined by how tight of a tolerance zone is required.
Flatness specifications down to around 10 microns or about 4/10,000th of an inch are quite common in machinery.
Those mating and sealing surfaces found in car engines can be found at this level of flatness. Sealing in fluids at this level of flatness requires the use of a gasket.
Field testing flatness at this level is done with a known precise flat edge and a clearance probing tool known as feeler gauges.
Actually measuring the flatness of a surface is a lot more complicated. An obvious solution would be to measure the surface against a flat reference. For example, if a part has a surface parallel to the surface to be measured it could be placed on a surface plate. A surface plate is a flat plate used as the main horizontal reference plane for precision inspection. A height gauge could then be used to probe the top of the surface for flatness relative to the surface plate.
If we first place the part to be measured upon 3 columns with adjustable heights. Then, with a height gauge, run the probe across the surface while looking at the amplitude of the needle, we get a snapshot of the difference between the highest and lowest point on that surface.
Automating the process with the use of a coordinate measuring machine or CMM is a common practice. CMMs are typically computer-controlled and can be programmed to perform the tedious repetitive measurements.
Going beyond the 10-micron levels of flatness requires the use of surface grinding. This process typically used to produce precision parts, precision fixtures, measurement equipment, and tooling.
Lapping is the process of rubbing two surfaces together with an abrasive between them in order to remove material in a highly controlled manner. In lapping a softer material known as a lap is "charged" with an abrasive. The lap is then used to cut a harder material. The abrasive embeds within the softer material which holds it and permits it to score across and cut the harder working material.
Wringing is the process of sliding two ultra flat faces together so that their faces lightly bond. When wrung, the faces will adhere tightly to each other.
This technique is used in an optics manufacturing process known as optical contact bonding.
When an optical flat's polished surface is placed in contact with a surface to be tested, dark and light bands are formed when viewed with monochromatic light. These bands are known as interference fringes and their shape gives a visual representation of the flatness.
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oxtoolco (Tom Lipton) - Precision Lapping 101
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Joe Pieczynski - How to Accurately Inspect a Flat Surface
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[@timorieseler276]

So, when flat earthers claim the earth is flat, maybe they're just working with higher tolerances...

[@jongwookmah603]

Incredible. This man needs to be the next President.

[@silo3com]

The earth is flat in the context of a human being. The sun also revolves around the earth from our perspective. It isn't accurate to take only the scientific perspective.

[@martynridley3671]

@@silo3com From our perspective, the sun merely moves across the sky. It's science that tells us otherwise!

[@colemanadamson5943]

@@martynridley3671 Indeed! Science - so called. Nowadays men believe what used to be called the "idiot box" instead of their own eyes!

[@martynridley3671]

@@colemanadamson5943 'so called', 'idiot box'?...explain what you mean.

[@NewMind]

To everyone wondering why the video cuts off abruptly, I lost the last 2 seconds of my audio file. It's supposed to end with "At these scales, the definition of flatness quickly becomes moot."

[@hipser]

Never apologize, you are a perfect ray of sunshine.

[@paint4pain]

Top marks for the way you explained how to get a reference surface without getting bogged down into datums and such. Also, I have the same set of old Russian optical parallels, I just need to find a lamp for them, my LEDs aren't monochromatic enough.

[@jimviau327]

Great video. Thanks for explaining the missing end.

[@AlessioSangalli]

What about a reupload?

[@si98justme1]

I thought it was deliberate and brilliant!

[@alexisandersen1392]

"The definition of flatness quickly become..." Become what.... BECOME WHAT?

[@kubacube342]

moot (whatever that means)

[@alexisandersen1392]

It doesn't really matter.

[@hawkhawkens6100]

Endless

[@alexisandersen1392]

eight

[@cillacowz2668]

Muh

[@jeffklaubo3168]

"Do you want to experience true level?" -Rick

[@micahlindvall285]

This is all I could think about watching this video.

[@ChargedTTq]

I came to the comments to find this comment.

[@Toxicity1987]

Funny enough, booth are not compatible. A perfect flat surface is not level because a perfect level surface mimics the gravitational force of the Earth.

[@jeffklaubo3168]

@@Toxicity1987 listen here... captain buzz-kill...

[@james4wd236]

The second I saw this video that's what I thought of.

[@jonanderson5137]

The gaskets aren't just for imperfect surfaces. They are for materials that grow, shrink and warp with heating and cooling... Every component in an engine bay for example.

[@PhthaloType]

Especially dissimilar materials that expand and contract at different rates (e.g. iron block and aluminum head)

[@Rubixdecampo]

Very true.

[@RunDub]

Old air-cooled Porsche engines don’t even use head gaskets. They rely on the thermal expansion of the materials as the engine heats up,and the precision machining of the parts,to seal the combustion chamber.

[@dilligaf0220]

@@RunDub Which is why air cooled Porsches need a $17k rebuild/remachining every 17k or 3yrs.

[@MyriadSkies]

Right, so it becomes imperfect somewhere along the lines =P.

[@realhealthquotesllc2195]

Nice video, but it ended flat.

[@hipser]

your whole life is flat

[@phillhuddleston9445]

@@hipser Your head is flat :(

[@neriksen]

Real Health Quotes, LLC ..... You mean it left you feeling flat

[@WernerBeroux]

The Earth is flat. Wake up!

[@canlib]

@@WernerBeroux you're asleep at the wheel-sphere

[@MikeBova1]

My wife says she's flat I told her she's within tolerance

[@Grannybang35]

😂😂

[@jagtan13]

@@albratgaming2348 I think we lost him bud!

[@MikeBova1]

@@jagtan13 sorry guys I had to sell everything to get her implants, now im stuck reading the comments at the local library

[@jagtan13]

@@MikeBova1 you're alive! 👍

[@MikeBova1]

@@jagtan13 I'm still sleeping with one eye open because... you never know

[@tncorgi92]

I took a tour of NASA's Glenn Research Center in Cleveland, they created a sealed room with an absolutely flat floor, within some microns of tolerance. I can't remember what kind of testing it was used for but they seemed pretty proud of it.

[@DDKolt]

It could be for the James Web space telescope. Smarter Everyday has a video about it.

[@GeneralKenobi69420]

At those tolerances I suppose it pretty much looked like a mirror

[@SH-bl9wh]

Saying something is 'absolutely flat' is like saying a square is a circle. No such thing as something completely or absolutely flat.

[@alexh5725]

@@SH-bl9wh Bruh, they specified "absolutely flat *within some microns of tolerance* " that's definitely not saying something as stupid as "a square is a circle" , and isn't even saying it's perfectly flat. Why be so pedantic?

[@p.g.3806]

I like the idea of a NASA scientist hosting a house get together, boasting about his extremely flat living room. ‘Ya, its within 5 microns, using statistical sampling.’

[@Volcanoelectricity]

I think you missed an important part of flatness which is the 3 plate method, who's discovery allowed us to create flat surfaces without the need for a known flat reference. We couldn't rely on any of the methods you showed in this video without the use of external flat references making up the machines and tools used to measure them. The 3 plate method gave us those first reference surfaces.

[@RealHankShill]

Thank you, I am glad someone mentioned it, even though I had to scroll halfway through the comments to find one of the most important inventions in machining history.

[@RealHankShill]

Thank you, I am glad someone mentioned it, even though I had to scroll halfway through the comments to find one of the most important inventions in machining history.

[@allennelson1987]

I think I have an idea of what you mean by three plate method, but from Wikipedia's explanation, it sounds like it would only create a plate that is round, they could easily create a dome shape or a crater shape.

[@goodkopbadkop9054]

whose* discovery

[@williamhinrichs6558]

@@allennelson1987 I find that Wikipedia often times has explanations that are technically some of the most correct definitions or descriptions of concepts, but not always a good explanation for someone unfamiliar with that concept. You are correct that if you only had 2 surfaces to rub together, you could eventually get them to mate to one another near perfect (or perhaps even perfectly), but that doesn't guarantee that you also have 2 surfaces that are flat, only that they mate/fit together perfectly. The 3 plate method successfully cancels out some of the "doming" effect as you called it (convex and concave surfaces) and with multiple cycles of choosing to rub different combinations of 2 of the 3 plates together, can achieve some of the best flatness achievable by mechanical means. This is going to be an over-simplification, but I think it could help understand the core concept of what makes the 3 plate method work. Imagine you had your first plate that was kind of dome-shaped. To clarify, that first plate is thinner on the edges and protrudes in the middle. When you rub it together with a second plate, it would make the second plate like a dome, but in the opposite direction, right? Like thinner in the middle and a little thicker on the edges, so that it matched and fit perfectly with the first plate. Well, do the same thing, but set the second plate off to the side for right now and bring in a new third plate to replace it. You'll be rubbing that same first plate, the dome-ish one against this new third plate until they fit together again, making the third plate pretty close to how the second one was, thinner in the middle, and thicker around the edges. At this point you set that first dome-shaped plate aside and focus on the 2nd and 3rd plates. What do they look like? Well, they've both got that anti-dome shape, where the edges are kind of raised and the center of the plate is a little recessed/sunken compared to the edges. These two plates are by no means identical, but they are close. If we were to set those two plates against each other, with their anti-dome faces in contact, what would be the surface that would come into contact? Since both have the edges protruding compared to the center, the edges of both of those plates would touch first. If you rub plates 2 and 3 together, you will be almost guaranteed to wear down the raised edges before you wear down the middle (there's proper techniques to follow here, but again, I promised a simplification). So now plates 2 and 3, after having their raised edges be the first thing to be worn away, you're left with 2 plates that have had quiiiite a bit of that dome-ishness removed from their surfaces. There's a ton of other interesting stuff going on, but hopefully this explanation serves as a foot in the door, and you can increase your understanding from there. I think important terms to understand that could help with reading technical literature on the subject would be: 'abrasion', 'bearing', 'concave', 'convex', 'plane'/'planar' Additionally, when I was super confused about the whole thing, I was able to find some pictures that finally made the core concepts "click" for me. Wikipedia doesn't always have illustrations that make the most sense, so if you don't immediately get it after reading a short, technically-worded summary, don't worry about it, keep searching for an explanation that you understand, and if you don't understand it, try to find exactly what about it is confusing you and search that concept, or just find someone and ask them how that things works.

[@LiezerZero]

Morty knows true leveling.

[@Yora21]

I know about the water and the bubble, Morty!

[@samuelvreede770]

Rick

[@adammada511]

and there it is lol!

[@SpecialEDy]

Lambs to the cosmic slaughter!

[@YanaiSachs]

I dabble in PRECISION

[@ShazyShaze]

*Me, an A-cup:* "Finally! A youtube video just for me!"

[@boncattoo]

Very nice pettan.

[@SinCosILoveIt]

Rushia wants to know your location

[@wilsonwilson3674]

I was waiting for this type of comment, ngl

[@justforshit57]

You will never be a woman

[@diobrando2160]

@@justforshit57 Redpilled

[@soldtobediers]

Tickles me now to recall the Metrology class back in the early '90's; where the statement that even the thought to be flattest surface, still sits on just 3 of its highest points.

[@Nerfornothin111]

This should be a required video to watch for mechanical engineering classes.

[@timhallas4275]

This should be a required video to watch for flat earthers. They actually think the surface of the oceans are perfectly flat.

[@T0BBi94]

Not so much for mechanical engineering classes as for material science classes

[@misternintendoman]

I've had a Metrology class as a Machinist that taught me about these topics, it's actually sad that this is not mandatory for a mech eng, this is why i always say a great Mechanical engineer is one who was a machinist first.

[@SuperDeinVadda]

I kinda know 90% of the content already. So showing it would be highly appreciated but may not be as necessary as you think.

[@APage-hn6cz]

Last two minutes really squashed this machinists mind. Good video.

[@JohnD595]

Austin Page i worked at a grinding shop for about a year. Those last 2 minutes were normal to me 😂

[@randommcranderson5155]

Search for a video by Andor Gafotas titled "indistinguishable from magic: manufacturing modern computer chips". It's a talk from 2009 that does a really good job describing some of the crazy manufacturing that goes into modern chips, with thin film deposition layers measured in atoms and the result having to be within 2. As mentioned, the talk was in 2009 and he wasn't talking about trade secret cutting edge stuff even then, and its also relatively large scale manufacturing, not experiments in labs done for papers. It's about an hour long, though. Worth a watch.

[@Villains_Nate]

only a machinist knows there is no truth, only "within tolerance"

[@stevethea5250]

@@JohnD595 I sent this vidnto my gf as a joke 😏

[@operator8014]

Yeah, nobody but OOOOLD timers that don't understand new systems really do it like that anymore. Modern electronics do a better job, faster, and often cheaper than a good optical flat kit. Less maintenance, and cheaper calibration and certification too.

[@privatepilot4064]

Very well done. As a retired Certified Mechanical Inspector and Metrologist, I found many people not familiar with GD&T would have a difficult time understanding flatness. They would always get it mixed up with parallelism. Flatness is essentially a characteristic measured to itself. I sure miss those days.

[@howtoguro]

Metrologists Unite! (We do not predict the weather)

[@stephenkrambeck6589]

I’ve had a pretty interesting perspective on flatness going from woodworking to becoming and engine machinist.

[@randoprior4130]

It very quickly goes from "eh, wood glue will fill the voids" to "yes it is perfectly flat but is it REALLY FLAT?!"

[@matthewcornelius5862]

Totally opposite for me. I have been a tool and die maker for most of my career and now just getting into wood working. Needless to say it has driven me to the edges of insanity.

[@bryandraughn9830]

@@matthewcornelius5862 Oddly, when your mind is working towards an exaggerated level of perfection, your woodwork will "pop" when completed. People will ask "how do you do that?" It's a culmination of many tiny compensations working together. Works every time too!

[@dietcurt]

I see the KZbin algorithm has brought us all together again. I hope you’ve all been doing well.

[@kinga6347]

My happiness is immeasurable and my day is saved

[@zoesdada8923]

Best comment of the year

[@Asdayasman]

I haven't! But thanks.

[@diegohuijbregtsgarcia5102]

It did it again. I was so surprised to see a comment of my own on this video, goes to show how easy it is to consume and forget.

[@stephenk.5839]

They knew I would be one of the suckers who could not resist clicking on to the bait for a subject such as this.

[@BrilliantDesignOnline]

I have a special butter knife I use to spread the atoms out evenly for perfect flatness. Only works with monochromatic blackberry jam, though.

[@SuperDeinVadda]

So if it doesn't work with butter, why call it a butter knife? Surely it is a monochromatic blackberry jam spreader knife

[@nowvalleydiorama885]

I'd love to see a video on flattening peanut butter with your knife.😂

[@BrilliantDesignOnline]

@@SuperDeinVadda You are right: an MBJSK; make NASA proud using TLA's

[@2x489]

i feel like i am reading an scp file

[@BlackSoap361]

@@SuperDeinVadda it does amazing things with butter, too

[@alanwatts8239]

12:37 -At these scales, the definition of flatness quickly becom *ERROR*

[@TerkanTyr]

Imagine making an engine that is bonded by spontaneous cold-welding due to perfect flatness in a vacuum. You couldn't open it to check it I guess but fuck it, it would be impressive.

[@AJ213Probably]

Space manufacturing is going to be great

[@timmyopally]

@@AJ213Probably "I'm tired of this (lack of right to repair) grandpa!" Elon: "well that's too damn bad!"

[@clarence4343]

It would be cool if it worked, it would be good if the head and block were the same material otherwise heating and cooling would warp the surfaces and create a mess

[@cyalknight]

I had an idea for a 3D printer using cold welding in a vacuum. The "pixels" would need to be cubes or something with a flat edge.

[@chasethompson7392]

Just wait til subie owners hear about this

[@AnAmericanComposer]

The beginning of this video reminded me of Joe Pera Talks You To Sleep

[@michaelbook2019]

Would enjoy hearing Joe Pera reminiscing about all the delicious holiday meals he's made on those lovely flat granite countertops.

[@zaidkhan7133]

Im here from school

[@The_Real_Daniel]

The most under rated video on youtube

[@stephenk.5839]

A voice that is smooth and flat, within the tolerance zone, will induce lethargy which progresses to the suspended consciousness known as sleep.

[@celticknotbrain]

I feel compelled to inform you that while watching this i fell asleep and dropped my phone on my chest. Then picked up my phone and immediately saw your comment. Real life never felt so scripted.

[@genin69]

quickly become moo? I knew cows ruled the world! goddamit

[@deadfreightwest5956]

Cow pats are flat.

[@nebtheweb8885]

Moot.

[@Derpy1969]

“We love our Moo!”

[@fcfdroid]

😂 😂 True i thought the same thing

[@shredo2]

came down to comments looking for this.

[@GuidoHaverkort]

"At these scales, the definition of flatness quickly becommb-" **has stroke**

[@ADVBear]

Some say he is flat on a bed to this day.

[@peterraffin2227]

Very well explained.. I think that all of this can only make sense once you've gone through trying to manufacture parts to flatness levels between 5 and 20 microns in large parts. We've found there's very few machine shops in the world that are capable of doing this work reliably over a long period of time. As you say, half the battle is actually measuring accurately in a repeatable manner.

[@OmmerSyssel]

Which sort of sophisticated industry are you working with?

[@peterraffin2227]

@@OmmerSyssel mass spectrometry

[@JanDrebes]

Thank you. This is my real job. You have present it very interesting and correct 😃👍

[@ADOBEFXPRO]

Ok, but what's your fake job though?

[@MatMabee]

What do you do and how can I begin? You look very well off. :)

[@ringlord13]

@@MatMabee Find a trade school or community college that teaches machining or better yet, Metrology (Science of Measurement), though there are very, very, few Metrology schools. My graduates regularly start around $24 an hour and get very close to six figures (with overtime) within 5 years, after only two semesters of Metrology training.

[@ghoulbuster1]

Thanks for making flat stuff

[@linusteir]

@@ringlord13 curb your expectations, i maker under 16$ an hour with an BA at an NMI

[@karoma7898]

Aaah, mechanical engineers should watch this in their first semester

[@inorite4553]

Mechanical Engineers should be exposed to this in their first internship.

[@arjun6358]

@@inorite4553 if only we had a proper internship

[@diegohuijbregtsgarcia5102]

Coincidentally, I'm in my first semester of an automotive engineering program.

[@epistte]

Geometric dimensioning and tolerancing in drafting/CAD was the introduction to this subject to engineers.

[@joser9237]

And any Machinists. I actually worked as a surface grinder, this video glossed over some details but it is exactly what we did. Really any soon-to-be machinist must learn this.

[@sethbettwieser]

I work with similar stuff: roundness and straightness.

[@JaczSolar]

Incredible video. Metrology is such an interesting field.

[@kanyarfuro]

Hands down, one of the most unerrated channels. Thanks for the educative yet quality content. Just binge watched your videos. Congrats and cheers :)

[@DogClutch]

Geometric tolerances are incredibly important in manufacturing and design processes. Excellent presentation, keep making videos of this calibre sir!

[@epistte]

This is better explained than the labs of my manufacturing process courses and GD&T class.

[@quaxenleaf]

Absolutely fascinating- and great info for those who may have a limited understanding of materials and manufacturing. Thanks for this!!

[@andrebartels1690]

Thank you for this quick look into this very interesting field. I especially enjoyed to see the different testing devices. The lens that uses monochromatic light is fabulous. When it sits in its case, it just looks like a piece of glass, until you use it properly.

[@jadefalcon001]

Extremely high production value. Well researched and presented. Terrific work! Subscribed. Looking forward to seeing more of your work!

[@Ahmed4th]

As someone who works in the engineering and manufacturing industry, I loved this video. I’m subscribing to this channel, I hope to see more of this kind of content here.

[@traumatic_]

nerd

[@fredcscully]

"Have you ever experienced true level Morty?!!"

[@KnappstersaurusRex]

As a CMM programmer, it's always cool to see popular videos like this introducing people to what I do! Great video.

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@kylez9094]

@@SighsInternallygage blocks

[@nukeemwins4174]

The only way to obtain perfect flatness is to leave a bottle of soda out on the counter for a week.

[@koikoi9817]

Then it will finally be drinkable

[@NuViss]

Nope! It will be slight curvature (comparable to roundness of Earth) in there ;)

[@theyseemeloling]

pop*

[@Colonel_Overkill]

@@NuViss also will be curved due to the skin effect of the water that it is comprised of.

[@SH-pc4xt]

Only if you open it first!

[@stevenbodo965]

10:17" ancient Soviet technology! :D

[@stephenroberts7459]

Thank you, that was very interesting! Is there a similar measurement of sharpness?

[@waveboard111]

as someone who gets structural design courses, and works at a tool manifacturer, this is amazingly well produced and well informed i love it

[@larrylund2682]

Nobody actually asked a quality inspector. Tons of guessing going on in this video. It provides most of the basics but, we need more information on how the Flatness is actually called out. Is it to itself or in relation to other datum points?

[@epistte]

Drafting 101 GD&T.

[@jockellis]

I liked it, too. I worked in a GE Energy machine shop that had 16 CMMs, both in final inspection and on the shop floor. I did NDT but was enamored with all final’s cool tools.

[@ringlord13]

@@larrylund2682 Flatness is a form only control, it cannot have a relationship to datums. If a print references either the ASME or ISO GD&T standard and it had a feature control frame with Flatness AND datums, the print is in error and wasn't produced per standard. I agree that it is a great introductory video, but one getting into the level you are asking for would be significantly longer.

[@jim6265]

Great video! As retired mil and new machinist, I found this very informative and well presented. While working on my education as a machinist I took several engineering and GD&T classes. Every little bit of info helps.

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@IFearlessINinja]

@@SighsInternally Gage blocks or Gauge blocks

[@NCshooter1213]

Down the youtube rabbit hole again. Now I'm looking around my house and yelling my wife things aren't really flat. The looks im getting are priceless

[@hootinouts]

Very good job of explaining the basics of flatness. My background in is tool and die making and design and all of what you covered was the world I lived each day. I ran surface grinders and have to maintain tolerances within .0001".

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@Retox5]

I work for Keysight Technologies, and we manufacture glass in very high-end specification for laser measurement systems... I am going to go quiz the glass manufacturing team, because this was the coolest video!! I had no idea of some of the specs that could be reached with flatness!! Thanks for sharing!!

[@barthooghwerff1682]

Very interesting video, as a knifemaker its easy to achieve high level of surface roughness but flatness is a real challenge and something to keep improving on!

[@Chris119.]

around 9:30 the concept of wringing... that blew my mind. I had a co-worker several years ago who used to work in calibration and described this to me as one of the tools they used, calibration blocks. That's incredible hat surfaces can just bond like that. I guess it essentially created a vacuum between the parts because they are such a precise fit even air can't get between them.

[@Brightly2109]

the tight script and ambient music make for a very immersive experience!

[@dmitriyk6962]

10:25 lower left portion of the lens... Love the CCCP technology

[@mikihisakaribe2319]

СССР

[@GbpsGbps-vn3jy]

Do you have an idea from where we can buy that lens?

[@udafflong1619]

Also sitting and smiling =)

[@coloradostrong]

@@GbpsGbps-vn3jy YES! After reading your question I found your answer. But it doesn't have the CCCP logo. Here: www.edmundoptics.com/knowledge-center/application-notes/optics/optical-flats/

[@delirio1987]

great video. the only thing missing is the beauty of hand scraped surfaces, which would add to the difference between flatness and roughness

[@lordchickenhawk]

Also, the "three plate method" deserves a nod in that context. Hand scraping (and lapping) combined with the three plate method is what gave engineering its first accurate reference surfaces for flatness

[@bodyno3158]

@@lordchickenhawk The dawn of precision manufacturing.

[@Industrialitis]

@@bodyno3158 That is a wonderful video!!!

[@moreno3461]

Thank you for your work! Great video! What software do you use to make animations with the blue background?

[@jrodthegreat1]

being a machinist we use precision measurement tooling and there are some tables that we use specifically for measuring or hand sanding something. those tables are made out of calibrated slabs of granite.

[@siggyincr7447]

Very informative and well edited video. If ever you chose to revisit this topic, a concern when you start approaching high level of flatness is that temperature differentials throughout the part being measured can significantly skew the results making climate acclimatization an import step before measuring. I've seen toolmakers and engineers struggling with inconsistent readings for weeks only to find out that parts need to sit in the QC room for a while till they acclimate. Otherwise mounted on measuring fixtures can pull the heat out of one part of the piece while the rest is still warm causing it to warp.

[@markkoot5318]

I used to flat lapp seals for pumps and they were perfectly flat under the glass when they came of the machine but once they cooled a little the light bands I saw didnt make me happy anymore so yeah temp is a big deal

[@mohammedobeed714]

Chances are I'll never use this knowledge, but its still very intriguing and I'm glad I watched it. Thanks for the info

[@jonrutherford6852]

Found this channel because KZbin algorithm "recommended" it for me. For once, KZbin got it right! Truly interesting subject matter explained about as clearly as possible and with good graphic support. A winner -- thanks.

[@xw591]

Wow! The optical measuring blows my mind! Cool!

[@LitchKB]

Pleasant, concise delivery of knowledge - thanks.

[@ryanburbridge]

Well i see this channel going places. Right up my ally. Earned a sub on first video

[@Asdayasman]

Meanwhile my boy out here rubbing three plates together in turn to make the flattest thing I've ever seen.

[@mckenziekeith7434]

Triple lap.

[@Jaxck77]

One of the flattest surfaces we know how to produce is pure molten tin. Aluminium has a similar effect, however when it is in its pure molten state it must be kept prohibitively hot to prevent oxidizations forming and ruining the flatness. It’s one of those cool properties I wish more factory games would play around with, needing to maintain a constant supply of a consistent molten metal.

[@hfso372]

i wonder if you could get it to harden in an place without gas that reacts to it and keep that flatness

[@mirko241]

@@hfso372 You would have to cool it down really slowly, within non-reactive atmosphere. Possible but not the best way to achieve flatness

[@trollmcclure1884]

actually it's as round as the Earth. And mica is flatter and solid

[@Jaxck77]

@@hfso372 You can. It’s a fucking nightmare, which is why it’s almost never done.

[@TheTarrMan]

As someone who works in a machine shop and deals with "the great struggle" daily, I can say this video was well done.

[@MrMccurley]

"The great struggle". Yeah, that about sums it up. I'm in the same trade. Perfection is an unachievable goal that some of us struggle to achieve anyway. After tossing the manager in to the chip bin, and getting on with it... ;)

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@TheTarrMan]

@@SighsInternally Those are called "gage blocks". The ones at 9:40 appear to be ceramic (higher quality, ridiculously expensive) while the ones at 9:30 appear to be the steel "shop grade".

[@user-uw1wq9rj8g]

What the heck!! This amazing video comes from channel which only had 14K subscribers?? This channel should get millions of subscribers with this amazing explanation and quality content!!

[@Larpy1933]

Excellent work here. Your use of language is unusually precise. Thanks.

[@davidrave563]

Your content is always so great!

[@davidreinhart373]

How does this channel only have 4.3K subscribers? That's insane! You should do collaboration with "It's Okay To Be Smart", he invites people to his channel just to say a few word and then links to their videos. I guarantee you that your subscriber count would rise at least 10 times.

[@NewMind]

Ill look into that. i have no I idea what edge I’m missing to get huge. Growth has been slow and constant though and the sub support has been awesome. Thanks for the kind words!

[@chrisedwards3866]

@@NewMind Your channel has the content and production quality for older channels with more subs to be willing to collab - though it can take a while to find channels looking to make a video on the same topic as you, and where the schedules work. You're on the right path, and making videos the right way.

[@jonathancrawford6919]

I seriously wonder this as well. The quality of scientific/engineering information here is even better than Real Engineering. I think this channel's author might need to invest time into the marketing concepts of how to grow a YT channel; an advertising and marketing adventure and skill set that is very different from just making excellent science/engineering videos. Just don't stop making the videos at least. They rock.

[@BenMarvin]

I know right. This channel needs a million subs by this time next year.

[@phillhuddleston9445]

Well now he has 5.9K.

[@PM17E5]

10:33 lol no Russian can miss the CCCP logo on that glass.

[@coloradostrong]

Да, товарищ! Хороший глаз.

[@jkurtc7457]

@NewMind Hey, I just wanted to tell you that I really enjoy your take and explanation of science topics, it is super engaging for me (31) as well as my daughter(8) perfect balance no matter what age or knowledge level!

[@bjallsop]

Nice work. Very informative.

[@393strokedcoupe]

You showed a clip of Tom Lipton from his KZbin channel oxtools. He has many great videos showing how to create flatness, the science behind it and tooling used to achieve it and how to measure flatness. Tom is a pretty awesome teacher.

[@ClockworksOfGL]

My great grandfather used to make precision surface plates. Lots of hand-scraping.

[@BestLittleStudio]

It is amazing what the human hand can feel as far as minute changes in thickness and surface uniformity.

[@dipi71]

I really admire the look of scraped and flaked surfaces. Hadn’t had opportunity to try it myself yet, but there are many videos about the process. Cheers!

[@ClockworksOfGL]

Jim Henline - It was many years ago when my grandfather explained the process, but I recall him saying it involved multiple plates and different colored “leads”, which would show high spots when the plates were rubbed together. My grandpa was a toolmaker himself and hand-finished a 90 degree angle just by lapping it until no light passed by when it was held up against a master square. I had it checked by a metrology calibration lab a few years back and it was accurate within 20 millionths/6” or something insane like that. The old man was really something else - he even specified the exact concrete formation for the foundation when he built his house.

[@keiy.4031]

@@ClockworksOfGL You can still get Prussian blue dye which marks the high spots. The stuff he must have used was red lead, or minium. Not so healthy for you, but you can still get the powder as a paint pigment and mix your own compound for hand scraping

[@woozhi9218]

@@BestLittleStudio i doubt it ,total flatness was made with three plate method three decent flat surface correcting each other.

[@jeffquantrill5570]

Wow! Thank you for this, my dad was a Metrologist who spent his life making slip gauges and even taught me to lap and perform optical flatness tests

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@BELCAN57]

I just retired after44 years in Aerospace Quality and Engineering. This is one of the best general explanations on this subject that I've ever seen. Great job !

[@SighsInternally]

do you know what the things at 9:30 and 9:40 are called?

[@BELCAN57]

@@SighsInternally They're called "Gauge Blocks" usually made of extremely hard steel for wear resistance (although ceramic blocks we're in favor for awhile), they are precision ground on opposing faces - with a surface and finish that is so fine that they are able to be "wrung" together and will "stick" to each other (as in the video). They have various uses in Manufacturing/Quality Assurance applications.

[@routtookc8064]

and ensuring the work is uniform in its temperature to avoid thermal induced error.

[@soaringvulture]

@carpe diem Imagine if the top of a "flat" plate was warmer than the bottom. The top would expand, causing the plate to warp. This affects flatness.

[@genixia]

@@soaringvulture Yes, a 1 degree Celsius difference in temperature between the top and bottom of an AA grade surface plate can throw its flatness out of tolerance. Even without a thermal gradient, materials expand and contract less at their edges, so a surface plate becomes convex as the temperature rises, and concave as it drops. Calibration laboratories go to great lengths to prevent thermal errors - tightly controlled environmental temperature, forced air circulation to prevent vertical thermal gradients, limiting the presence of 70+W organic heating elements (humans) to a minimum, even minimizing lights to limit radiated heat. It's normal to fixture components and gauges, then leave them in place for hours to normalize, then to take the measurements as quickly as possible before the human presence starts to affect readings. NIST have a great document on gage block calibration, "The Gage Block Handbook" , that describes the lengths they go to in order to accurately calibrate gage blocks. Personnel wear mylar capes, cotton gloves and use insulated tongs in order to prevent human heating effects. They even worry about different surface finishes absorbing radiated heat at different rates affecting comparative measurements which they use to reduce uncertainty errors. Yes, thermal errors are very real

[@keiy.4031]

@@genixia Yep. I have an inspection block level for leveling machines and it's good for 2 arcseconds, or .0001" per 10". You'll see the bubble start to move if you touch the level, breathe on it, or let a sunbeam hit it. It's a good demo to show people how even minuscule levels of heat can change your measurement. It also makes me wonder why so many shops don't bother with the expense of a temperature controlled shop so the machines can take full advantage of the thermal stability of the environment. The chiller systems can only do so much.

[@geraldstewart]

@@keiy.4031 I calibrated these

[@milo-uy6rd]

This is very very informative! I learned a lot from this.

[@chdarwin05]

Very cool video! Learned several new things I did not know and had forgotten.

[@Renwoxing13]

The flatness causing objects to bond is one of the most amazing things I have ever heard!

[@currentbatches6205]

It's even more amazing the first time you stick a couple of Jo-blocks together.

[@meoff7602]

It has to be the same material. Something this video missed, but clearly showed.

[@tomte47]

I got to show this to the new guy at the machine shop. He was supossed to paint a stamping tool, painted surface ground mating surfaces and when told to remove the paint he used a hand held angle grinder...

[@russellg1473]

Man I’m just out of HS machine shop... Sounds like maybe he didn’t really belong there in the first place lol

[@kevinspacey5325]

As a production tool maker/tool grinder. . . . you aced this video as far as I go. I've seen videos on how they shaped the hubble's telescope lens and it never ceases to astonish me how much more there is always left to learn in machining. We need to get more young kids into this field right out of high school and college because if we can't build, what are we?

[@joea5228]

Parasites?

[@babydriver8134]

I enjoyed polishing flats more than grinding. Second surface polishing was done with the work mated with the block by molecular cohesion as you have shown here. It was a great job but paid squat. Oh, one of my light boxes used a ruby laser.

[@Matando]

Interesting. So Uruha Rushia really is boing boing? 興味深いですね。潤羽るしあさんは実際にボインボインなんですね。

[@engineer9528]

12:36 "at these scales, definition of the flatness quickly become..." indescribable by words :D :D

[@Strothy2]

you sir just earned a new subscriber, I myself work in machining, flat really in most cases means I'm within +-0.01mm :D If you go over to the optics side they measure flatness in radiuses the size of the planet :)

[@aboriani]

Strothy2 and by radiuses of the size of the planet, you mean infinitely large radiuses, cause the earth is flat, everyone know that. And before anyone takes me seriously, yes, I am joking

[@bryanmartinez6600]

I just imagine you going to 0.02 and chuck whatever your making across the shop.

[@kexcz8276]

Wow. Exactly today, we worked with the magnetic grinder, and we grinded the surface of an steel cube. And the interesting thing is, how precise that grinding is, and even more mindblowing is, that thats not the best surface-fining method like honing, laping etc.... 😃

[@rextransformation7418]

9:20 And I always thought it was because there's a vacuum between the two surfaces... In the workshop we have some Mitutoyo gauge blocks; when I use those needed I make sure they are clean before joining them, and am always amazed how they bond together, just like in the video. But I always thought it was, as said in the beginning, due to a small vacuum. In fact, if I try to join them NOT by sliding them together, they DON'T bond. But if I slide them like in the video, they do bond. So I do think it's due to vacuum as the sliding pushes away the air, creating a sealed surface. But I may be wrong. Any ideas?

[@rugerdave]

Just an FYI, The proper way to wring Jo blocks together is to clean the surfaces of both blocks by placing a sheet of clean white paper on a surface plate and rub the surface of the block against the paper until the paper is clean, which is the same method to clean the faces on a mic (mike). Then wipe the face of each Jo block on the inside of your clean forearm, then wring the blocks together. If it's not done this way, the Jo blocks will start to get microscopic scratches on them and throw the calibration off. Wiping it on your forearm applies a minuscule amount of skin oil for lubrication. It's not a vacuum, both blocks are dead flat.

[@Rocksteady8519]

As a kid i was wondering about how the first perfectly flat object was made as in my logic that would require something else equally flat to shape or form that object and thereby creating a paradox. Then i learned that liquids are perfectly flat and also that there are many different methods to produce "flatness". And finally i learn that everything is relative and depends on reference frames and that you can not know everything about anything. There will always be uncertainty, thats the only thing we can really know for certain ;)

[@mduckernz]

Haha, yep. Even with optical methods there will be gravitational distortion so it's impossible to actually measure it as you can't get a true reference, only better and better approximations of it. But, once you get down to those lowest levels anyway, reality itself becomes kinda lumpy and not at all a thing where straight lines and such even have much meaning :p (like, what even is a flat surface? The atoms themselves have uneven electron field densities, like their shape undulates, so there is no flatness)

[@VioletGiraffe]

Liquids are not flat, though, they're curved along the Earth's surface. Which in turn isn't a perfect sphere. Fun fact: if the Earth was a flat disc or rectangle, spilled liquid would still not form a flat surface :)

[@Rocksteady8519]

@@VioletGiraffe I get your point but i feel some kind of astounded that you had to mention the earth is curving aka round... If Earth didnt rotate and was covered 100% with water AND gravity was evenly distributed along the entire surface, then it would be quiet close to being spherical no matter how many valleys and mountains it contained. (the moon would have to go at this point also) Liquids are shaped by gravity and surface tension to my knowledge so you cant really apply a shape to it. The "fact" you mention would be nice for others if you elaborated a bit on that part. I totally get it but other people might not

[@jaredkennedy6576]

What, were you some kind of ultra nerd as a kid? I guess I wasn't the only one pondering odd questions.

[@hunger993]

look up the 3 plate method

[@rubikfan1]

Dont you just love when thr youtube algoritem shows you somethings science instead of timewaste

[@neatt3815]

This video is a whole mood. I sometimes feel flat. Sometimes round. Or like an edge. Or a spike.

[@carlosbarrientos7915]

These videos are a blessing when you have the day off work, and your neighbor gave you a special brownie.

[@ShatNdd]

11:00 Like for "USSR quality mark" on the optical probe

[@martin09091989]

This clip and one other are from Tom lipton, a hobby maschienest and tool maker on KZbin. He got these Russian optical flats for cheap.

[@bagamax]

Flatten it harder, tovarishch!

[@Bob_Adkins]

Actually, the Russians are quite good with optics.

[@beanieteamie7435]

You my sir, have earned a sub!

[@cigarboxmaster]

Very amazing video of explaining this, sometimes odd, concept.

[@IVGHOSTLY]

As a mechanical engineer and cmm engineer at an aerospace company is makes me so happy to watch this.

[@andrewhickman9369]

My son asked me the other day if the floor in our kitchen was flat... ... Couple of days later, KZbin suggests this. Google is listening!

[@anunnakimenagerie]

you can change your settings

[@misternintendoman]

This is the best video you will watch about Flatness on youtube, well done everything said was correct, i love that you pointed out the common misconception about inspecting flatness and parallelism, many machinist will appreciate this video, thank you.

[@BigSp3nda]

I just came from how glass is made and they explain the tin floating glass part so this is spot-on I understand perfectly

[@compoundlml7156]

I work in a steel mill. My job is to grind skp rolls. Our tolerance on a roll 17" in diameter, 6' long is 0.001...I know all about flat lol. We also take a roughness measurement, and there is a tolerance for that as well. That would be a good video as well how smooth is something really.

[@JohnnyWishbone85]

10:17 -- Anyone else notice the USSR marking on the Optical Flat tool? Is this an old video clip, or is that an old tool?

[@bryceforsyth8521]

Old tool.

[@linmbritt]

Is that an old tool you have there, or are you just not that happy to see me?

[@dustdrop]

Very interesting information. I was surprised to find out that very flat objects will stick to each other. Very cool.

[@southjerseysound7340]

The first time I saw it in person I was blown away. Whats even crazier is you cant just pull them apart and need to twist them off.

[@rabie4x4]

And it's not "exactly" known what causes this.

[@PaulBednall]

Air pressure causes the objects to stick or rather the lack of air pressure between the surfaces does.

[@markc2643]

Could it be the Casimir effect? Microscope slides are packaged with a powder-like substance between them to keep them from bonding. Occasionally you find them stuck to each other permanently.

[@Fritzpuddel]

It's the Van der Waals force.

[@holeshothunter5544]

how does one make something (like that engine plate) with multiple (not) connected flat surfaces on it? those dis-connected surfaces must each be flat AND in the parallel, even tho the flats were not at the same vertical height from the other side's (reference) flats? That' a lot of surfaces to get (individually) flat yet all parallel to each other and parallel to the reference flat which if facing 180 degrees away? I just confused mysel writing it down! How is it done?

[@Frlja]

Incredible video! I am an economist myself, but I love to learn about these kind of things I followed everything quite well, until the greenlight part of video came up. Then I was like - ARE YOU A WIZARD :D incredible stuff

[@aftaev]

Плоскопараллельные стеклянные пластины из СССР (USSR) со знаком качества :)

[@a3sop]

Остатки древней, более развитой цивилизации.

[@RyanMcIntyre]

Hahahaha 😂🤣 good one

[@OlderSpud]

@@a3sop Цивилизации, которая развивалась, пожирая своих детей.

[@a3sop]

@@OlderSpud Детей?