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Spinning Levers – How a Transmission Works (1936) [video] (youtube.com)
116 points by userbinator on Aug 2, 2022 | hide | past | favorite | 41 comments

When I saw the date and topic, I knew this had to be one of the many wonderful films the Jam Handy Organization made for Chevrolet. Here are a few more:



One of my favorites isn't about cars, it's about how they made old radio shows and did the sound effects. Of course they do work some Chevrolets in near the end.

Back of the Mike:


You can make the argument that YouTube content creators more or less cover what was Jam Handy's domain once, but I am not convinced. There was a level of professionalism and an everyman approach that I have only seen hints of from modern YouTube creators.

I would love to be the modern Jam Handy. I wish they still showed this kind of stuff in primary/secondary school. (I wish we still had things like "shop class" too.)

I loved 7th and 8th grade shop class!

Of course I studied trigonometry in math class, but shop class was where it all came together.

The first half of each year was mechanical drawing. Whoever got the top score in mechanical drawing got to be shop foreman in the second half when we used the power tools to build things. (The shop foreman directed who did what in the cleanup at the end of class.)

Lucky me, I got to be shop foreman both years. I think it was because mechanical drawing taught me attention to detail. I learned to use the compass and straightedge, the eraser guard, and the French curve.



My only regret was that they split up the boys and girls for this hour: we went to Shop Class and the girls went to Home Economics where they learned to cook and sew.

I bet there were a few girls who would have liked to learn mechanical drawing and working with power tools. And I'd enjoyed cooking for years, and had been the family sewing machine repairman from a very young age.

It would have been nice if we could have all done both classes.

Especially when I think about how I might have impressed the girls when I fixed their machines!

We all did shop class and home economics where I’m from. It was wonderful.

Learned a lot about basic cooking and nutrition in home economics. Bet I still use many of those skills to this day without even realizing it.

The shop class stuck less. Perhaps because I spent a lot of my younger years learning mechanical engineering from my dad and got to “help” with power tools around the house we were renovating at the time.

Using the lathe was epic, though. My rocket came out extremely unbalanced.

Check out Jeremy Fielding on YouTube, you'll be subjected to his in-video advertisements for children's toys, but your comment about profesionalism and everyman approach made me think of Jeremy.

EDIT: this is jeremy's website: https://jeremyfielding.com/

There's definitely YouTubers out there that have those quality animations/explanations, one just has to dig for them unfortunately. They get drowned out by the algorithm-chasing videos and the low-quality content farm channels from developing countries.

There must have been a different mindset in the early part of the 20th Century. "The Boy Mechanic" [1] book series from Popular Mechanics are of the same pedigree. And a little later, the German "The Way Things Work" [2] twin set of books (sorry, not the newer books by Macaulay with the same name).

[1] https://archive.org/search.php?query=the%20boy%20mechanic%20...

[2] https://archive.org/search.php?query=the%20way%20things%20wo...

That Macaulay book was a favorite of mine at a certain age! I gift the newer edition to elementary-aged kids whenever I find the opportunity.

Truly a formative book. More than anything else it taught me that the world around me was tractable.

recently found "the way things work" at a book sale for 2 dollars! a beautifully bound shiny silver book with glorious orange and black illustration. Reminds me of my worldbooks from when I was a kid

I don't get the love for this particular video. It does a very poor job of explaining GM's 1930s sliding cone synchronizer. Here's a shorter modern video doing a much better job explaining how modern dog tooth synchros operate:


It does not do a better job. There are no schematic diagrams and it fails to explain fundamental principles first - just dives in with a verbal exposition using unexplained technical terms like "outer sleeve" and "baulk ring". I glazed over immediately. Its shortness is not a virtue.

These old videos explain things a lot better than modern educational films seem to.

Is it because modern topics are more complex? Or am I not representative of the modern audience? Or is this survivorship bias - this particularly good film has been preserved while other less good ones were not? Or are modern films just not made to the same standard?

The old videos are usually straight to the point, whereas the creators of modern videos seem to go out of their way to make theirs more “fun” and more palatable for the audience that suffers from the widespread attention deficit. The result is often a shallow and diluted circus of a presentation.

Each minute of final product had a much higher cost back then (more labor to film, more maintenance hours for a given number of film hours, more "effects" done in real life, expensive storage mediums, more laborious editing, etc) so they didn't waste time on fluff.

German kids’ books and videos seem to do a better job than American ones, though I can’t explain why. Must be some sort of cultural difference.

I myself only saw this video quite recently and like many in the YouTube comments my first thought was, "What has changed in the way we teach things that this video looks so refreshingly simple?" The first thing that comes to mind is the focus on visual intuition and simplicity, so that if you dragged someone randomly off the street, showed them this video, they could be able to understand it, what else?

>my first thought was, "What has changed in the way we teach things that this video looks so refreshingly simple?"

I think your perception that the teaching method has changed is just "availability bias": https://en.wikipedia.org/wiki/Availability_heuristic

People have always been making models and filming it to explain concepts. Today's examples on Youtube :

- toy models to demonstrate hydro engineering phenomenon (e.g. sinkholes) : https://www.youtube.com/c/PracticalEngineeringChannel/search...

- models to show science topics: https://www.youtube.com/c/TheActionLab/videos

- CGI models to show various technology: https://www.youtube.com/c/animagraffs/videos

- ... hundreds of other educational channels like the above ...

And before the internet, you had tv shows in 1980s with models to explain machines:


That transmission differential video should be notable because it is old and still relevant and not because nobody teaches like that anymore. The limiting factor even today as it was in 1936 is that it takes a ton of extra effort to build models to teach rather than write dry boring text.

I love that Tim was able to post all the episodes of "Secret Life of...", and then continue with new ones too. I enjoyed his book (https://www.timhunkin.com/40_rudiments_book.htm) as a child, and still have it.

Tim Hunkin is great and I've enjoyed revisiting his Secret Life of Machines on YouTube.

Actually, the original TV programme has a distinct flavour of YouTube to it - in the best possible way it has the feel of talented amateurs. Clear, entertaining and no excess polish covering up the personality of it all.

Don’t forget survivorship bias. I’m sure there were many terrible, unintuitive models in 1936–this is one of the few that was so good it managed to survive almost 90 years later.

I don't think there were many at all; the production costs were much higher back then, so if anything those who could afford to film would've wanted it done right far more than today.

I love this video like most people here, but it must be recognised that that demo apparatus was probably quite expensive to design and build such that it makes everything so clear.

It might be one of those things where if it's done right, you don't see any of the effort.

Edit: I assumed the video was this [0] one about how a differential steering works (containing an awesome demo)

Now I've flicked through the video it seems really expensive and I assume that big budgets just want to get higher viewing figures and so lean on the flair.

- [0] https://www.youtube.com/watch?v=yYAw79386WI

In the (good ol') times, to get a driving license (here in Italy) you had to have a basic understanding of how cars worked, including the engine, the gearbox, clutch, etc. and driving schools would have had a "fake" car with all the mechanisms visible (and working) so that the teacher could explain in practice how everything worked.

They were "pieces of art", examples:



You still do (to a lesser extent). How a transmission works is a typical driving test question.

Yep, but only a very few (old) driving schools have these models (that would be anyway largely obsolete), and those that still have them keep them only for decorative/historical reasons.

Now what is (usually) taught is not "how a transmission works" but rather "how to answer the questions on how transmission works" (which is different).

I think someone prided themselves in understanding the principles in such a degree that they were able to explain it to others in an intuitive way. Kind of the opposite of what we're doing today, where most people are bullshitting to some degree and need to hide that..

I really liked the fact that the video started with a basic principle - levers! It showed the viewer how levers work on a example that is easy to grasp to layperson, then went on to gears and their interactions. During the whole video the pictures were up-close, no clutter, no distracting cuts. Really nice.

No you're right. If YouTuber's did the same it would be mostly a talking head and perhaps a quick sketch on a whiteboard or equivalent. There is a certain quality to these.

One thing that changed is that appliances that used to be simple and worked by using mechanical parts that you could see and replace are now just one more thing with a chip inside. Watching a toaster work with the bimetallic strip that suddenly pops is appealing to the human mind in a way that "enh, it's just magic, like your phone" isn't.

I'm gonna guess that corporate resources were allocated to the production of this video, as opposed to someone trying to churn out content for a second rate youtube channel. Don't get me wrong, there's a lot of good new stuff being made, but I think there's increasingly more junk content.

Let's not forget the classic turbo encabulator explainer video:

* https://www.youtube.com/watch?v=Ac7G7xOG2Ag

* https://en.wikipedia.org/wiki/Turbo_encabulator

Here's one of my favorite explanation for how mechanical watches work: https://youtu.be/FhVGyvpLoxU

Mechanical design is something that completely baffles me and leaves me in awe. I can comprehend almost anything electronic/digital, but I just can't fathom how one would conceive of a complex mechanism (let alone package it in a compact form!), despite understanding the physical concepts behind them.

No doubt then you're familiar with the Antikythera.

You would think that more people would put two and two together but what baffles me is the dissonance in people's minds of ancient civilizations - namely that they were oh so primitive, but at the same time there is this underlying current of, "how could they have possibly known this if they were so primitive?" with the discoveries we find that they have left behind - whether it be mechanical, architectural, agricultural, whatever.

I think over all they were not much worse off intellectually than we are, but they haven't yet discovered certain things - much as we have yet to discover certain things. For them, it was a mechanical age for a very long time and they've mastered that in much the same way that we are slowly beginning to master electronics and chemistry. We've had a very, very slow ascent towards electricity until it has become commonplace as it is today. I doubt the design of electrical components that we can easily plug in and out with a bit of molten lead/tin would, to them, be anything short of wizardry.

So don't be distraught by the otherness of it. It is quite a different way to look at problems that really tests our understanding of first principles of the natural world.

What an amazing video for its time. I'm surprised they were do all these sorts of animations of arrows and power flowing on the gears without any cgi. Looks like it was hand drawn on a sheet of transparent plastic and added on later? No idea but the way they explained it was cool as heck. Learned something new today and I'll be more mindful of what is happening in my car when changing gears now!

Agree on the video comments.

This video shows unsynchronized, straight-cut gears and your car has two improvements over that: helical cut gears (much quieter) and synchronizers to aid (significantly) in gear shifting.

Except for reverse, in a street trans design newer than 50 years old, the gears themselves are constantly meshed and there are internal rings which lock and unlock the gears from the shaft they ride on. The synchronizers are softer metal rings that help to guide these rings into meshing as they turn past each other.

This video shows the parts well: https://m.youtube.com/watch?v=MXsRfbOiBhE

The video mentions synchronizers and shows helical cut gears at https://youtu.be/JOLtS4VUcvQ?t=409 .

Right you are [and my mistake/have an upvote].

When they made the cutaway back the guy shifting gears, I mentally took that as "ok, they've well covered the topic and this is just an outro", so stopped watching there.

What is it about these old videos that make them so much more comprehensible than modern videos. I binged a bunch of these maybe two years ago on Youtube and they are all fantastic.

The people making the videos are much more aware of who their audience is and how to communicate to them. They make the assumption their audience is intelligent, but unfamiliar with the subject material. So they avoid industry terms and jargon, and instead work on establishing understanding of basic principles in familiar terms then elaborate on them gradually. I've seen similar approaches in teaching people with no technical background how to write code, to great effect.

It's by no means easy to write such curricula though. What you're doing is taking a very complicated topic with expert-level information and translating it to non-expert language and ideas. It requires a sophisticated understanding of the topic, and good communication skills. By "good communication skills" I don't just mean being good at talking or writing, I mean the ability to empathize with and understand your audience's point of view, to anticipate their confusion as well as their understanding, and to handle both gracefully. It is important when writing these kind of explainers to not come off as condescending, and that can be especially hard to do when simplifying a complex topic.

I also love these videos, because they're a master class in how to communicate effectively.

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