The Science Of Small Distances

We explore the precise measurement and machining of small distances and their importance on modern industrial society. The history of the meter and distance measurements are explained as well as intuitive examples of small distances given, moving from mm scales to the realm of microns. Further, we discuss some of the engineering issues that emerge as we try to machine at smaller tolerances such as fitment, assembly, and thermal expansion.

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[NewMind]

In November of last year, I released a crudely made video on the Science of Small Distances. It was kind of a half hobby, half experimental effort and I had never expected more than a few hundred people to ever watch it. I still recall the excitement of hitting my first 500 subscribers from that video. And here were are, one year later, 138k subscribers strong and a silver play button fresh in hand. I can't begin to express how grateful I am for all the support you guys have given me. It's been an amazing adventure and I'm so thrilled to be sharing it with such an incredible and knowledgeable audience. I thank you all.

As the channel grew over the past year, I've always wanted to redo that first video that set everything in motion; refine the quality a bit, USE METRIC UNITS!, etc. I can't think of a more appropriate time than now - I present to you my anniversary remake of The Science of Small Distances.

[WarpedYT]

If you put two pieces glass together with a couple drops of oil in between them it gives you a great idea of how that thin film of oil works in the engine, it's also pretty impressive !

[LaGuerre]

"Many of the components we interact with daily such as buttons, switches, knobs, and other tactile controls operate with clearance fits in the 0.25mm range." Oh, that's all! Imagine saying this to a Renaissance or Industrial Revolution-era scientist. All the little things we take for granted in the modern world. Excellent video.

[phildavis]

Hey there! I am a retired engine machinist who ground thousands of crankshafts and bored and honed thousands of engine blocks, as well as piston pins and bushings etc. I saw the first video on this, and remember seeing some information that was a bit off. I have been subbed since, and have been watching your videos. Their quality and the information quality have been getting phenomenal! You have a really good skill there. Keep it up! As you went smaller in dimensions in this video, I kept comparing the information to what my experience told me, and everything was really, really accurate. I saw one tiny flaw, and maybe others mentioned it, but piston pins DO have a clearance fit, of about .007mm, so they do slip together at room temperature, although, as you said earlier in the video, it takes a bit of skill to line them up well. In most engines, the cast iron connecting rod bore end is heated to allow the pin to slide through, and it clamps on with great force when it cools. In a lot of diesels and industrial engines, the connecting rods have a bushing in them which also has the .007mm clearance honed in, (rather than the interference fit), and in these situations, clips are fit into grooves in the piston on either end of the pins to keep them from sliding all the way out. You may already know all this too, but I got anyway, great job! I would LOVE to be able to make videos like this, but I seem to be stuck on learning how to do animation. I think it's just a matter of 'drive'.

[bibasik]

"But how can a machine rotate so reliably for years without failure?"

Chrysler: They don't.

[ViscoseComb]

This is pretty much the only video I’ve found that has actually given me more than just a sliver of an idea about the size of atoms

[barnabywilde]

measure with a micrometer. Mark it with chalk. Cut with an axe

[grahvis]

This takes me back to the early 60s, where I have the most boring job of grinding the axles to +- 0.0127mm which were a press fit into the arm of the torque bar suspension for armoured vehicles.
The centre grinder I used had a plaque stating it was patented in 1896.
After that I went on to grinding crankshafts on a more modern machine.

[atomkinder]

As a point of reference, I work on linear motor 5-axis CNC mills that have a high-accuracy mode that promises a tool-to-tool measurement discrepancy of ±1 micron. In this mode the holder the tool is in, the spindle, the laser assembly, all must be calibrated at temperature and have specific runtimes in order to keep them all within the same temperature of each other, and warmup times designed around constant temperature both before tool measurement and machining take place.


For those not familiar with metric: one micron is about 40 millionths of an inch, or .00004". Human touch can distinguish about one ten-thousandth (0.0001") in surface difference.

[ropersix]

For those interested in this general topic, I recommend the book, "The Perfectionists" by Simon Winchester. It basically goes into much more detail about how all of this figured into the Industrial Revolution, including people who dedicated their lives to achieving all of this precision.

[scottibugatti]

“An engine can experience 500 million to 1 billion revolutions in its life”.
Honda owners in one night: Challenge accepted

[A.Lifecraft]

12:50 My dad worked in semiconductor quality control. He sometimes had to "grind down" into chips to take a look at certain structures, so he applied these pieces as big as a sandcorn to a holder and grinded them on plates of glas, molecules of highly distilled water being the abrasive material. For finer work, they used a focused stream of particles, where you can see in realtime what you just "milled away" by doing roentgen spectroscopy. Fun thing is, he referred to that process, where you blast away atoms one after another, as "burning a canyon into that surface and sift through the debris"

[krabkit]

"beyond the scope of this video"
can't wait for part 2

[shoam]

I don't remember the exact point I subscribed. But I remember a few things I noticed.
The first thing was that I noticed the attention to detail and the range of knowledge in the first video I watched. I knew this channel was definitely one of the few worth watching every video posted (even more than once), and I'm picky with which channels to which I subscribe.

However, I was surprised (and maybe a little disappointed) there were only 2 videos. But then I realized: the channel wasn't abandoned, just really new. Something I hadn't encountered before, a great channel at the very beginning.

[waynethomas]

Hey, great stuff! I went to school for "engineering drafting and design". Where I lived they didn't need people with 4 year degrees that still didn't know how to draw so the local college tailored it's curriculum to the work in the area. Important things like like fits, tolerances, metallurgy, material selection and most importantly, Computer Aided Drafting were of course covered but we also had to take the entire machine tool operations sequence which was the same sequence for a "journeyman machinist" might have to take. Many complained "I'm not going to work in a dirty shop", not realizing that it would make us better designers. In fact, if it wasn't for that sequence we never would have qualified for the jobs in the area detail draftsman and designers. I soaked up everything in college I could like a sponge. I took other cad classes that used different programs, "hydraulics and pneumatics"...whatever I could take that might allow me to be employable at a variety of shops. It worked. I didn't plan on working as a machinist in a welding shop but when layoff time came I needed the job. Unemployment didn't pay the bills! LOL I was taught mostly in inches because from the rollers at the steel mill to the finished sheets and bars, everything was in inches. You could special order hard Metric but only a couple of sizes might be on the shelf or could be had quickly. So, to this day, when someone starts talking in Metric, my eyes gloss over and I start looking for my calculator.

[davidclark]

I once machined a bore for a ball bearing in an aluminum housing, but my last cut went slightly oversize. This has happened to all of us, I realize. But I left the part in the machine while I figured out how to fix it, and when I came back hours later the part had cooled to room temperature and the bore had contracted to the right size. This was a bit of luck in this case, of course, but temperature matters when precise dimensions are required.

[Skybutler]

Your crystal clear and calm narration makes this in itself already interesting subject so much more accessible. Well done!!

[scootergem]

Call me subscribed! What a great video! No nonsense, accurate information presented with great voice over, clearly spoken. I just can't say enough. KUDOS!

[Strike]

Genuinely the most mind blowing video I've watched for a long time. I never knew that engine bearing clearances were so incredibly tight.
Amazing scale comparisons as well, really gives you an idea of the distances involved.

[thetinysideoftiny]

What an incredible video! Content, layout, explanation, pace, videography, voiceover…all PERFECT! It all adds up to presenting a complex subject in an effortlessly digestible and entertaining way. WOW! I loved it!!