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Frame from Spinning Levers - How A Transmission Works (1936) Plays via YouTube's privacy-enhanced embed

Spinning Levers - How A Transmission Works (1936)

3 videos recommended on HN
YouTube
5 HN users recommended this explainer5 months2018–2026 score 5.5
Years with an HN recommendation, 2007–2026

It is held up as a model of clear, well-paced educational film and of the old-era instructional style.

A 1936 Chevrolet-sponsored film that explains how a car transmission works by treating gears as spinning levers. It uses physical models to make the mechanism clear.

“The editing, pacing, and style were better.” (HN, 2019)

1 strong recommendations · 4 recommendations · 4 citations · Explainers

9 Hacker News comments

From the HN archive; up to 20 kept per video, favoring different commenters. Recommendations first.

@Animats May 2019 Strongly recommends
on HN thread Five Hundred and Seven Mechanical Movements (1908)
Read more
The editing, pacing, and style were better. Educational videos today tend to go to one of two extremes. Either they're a talking head with PowerPoint, like most of the "massively online" courses. Or they have way too many jump cuts, like theatrical movies which want your attention, not your understanding. There's also an annoying tendency to have distracting music and irrelevant graphics during narration. Here's an old Jam Handy film, "Spinning Levers", on how a transmission works.[1] There's a whole series of these Chevrolet films on the Internet Archive, covering major vehicle systems. Things to note: - There's a narrator and a demonstrator. We never see the narrator, and the demonstrator never talks. So the viewer can focus. - The demo models of parts are really good. They start with a simple version and add features until a full transmission has been built up. - There's some simple animation. Animation is used to point out how power flows through the gears. This is much clearer than someone using a pointer. - The editing and narration are very well synchronized. - There's an entertaining part at the beginning and end, so you don't feel like they're beating you over the head with the boring stuff. [1] [this video]
Model of good educational film editing, pacing and demonstration.
@jolmg Oct 2018 Recommends
on HN thread Why some things are darker when wet (1988)
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Lately, because of a car situation, I've been watching car mechanic videos online. There's some old videos, like 1937 old, made by Chevrolet, that explain really well how different mechanics of a car work. One explains a transmission starting from levers[1], how they work to give mechanical advantage, and how gears are basically spinning levers. I ended up feeling like I could make a basic transmission if I only knew how to make metal pieces in the shapes I want. From there I've been looking at people disassembling automatic transmission and explaining the different parts. I gotta say, learning how these machines work mechanical advantage to something so convenient has really raised my interest in physics and mechanical engineering. I don't remember simple machines[2] being something so interesting back in physics class. I don't blame the teacher, 'cause she was always enthusiastic about physics. I wonder why this is more interesting now than then. It's probably just that, now that I'm older, I can understand complex applications of those fundamentals being taught at school. [1] [this video] [2] [link]
Explains transmissions starting from levers and gears as spinning levers.
@MaxBarraclough Jun 2020 Recommends
on HN thread Strike a Solder Joint Behind Enemy Lines
A couple of other examples: an old US Army training video on the workings of various categories of firearms [0], and an old video on how transmissions work [1]. Both make great use of physical models of the mechanisms. [0] [link] [1] [this video]
Old video using physical models to show how transmissions work.
@_xerces_ Nov 2024 Recommends
on HN thread A 15-minute intro to involute gears
This old training video is great too, it also mentions the idea touched upon in the article that gear teeth are levers: Spinning Levers - How A Transmission Works (1936) [this video]
Training video that also treats gear teeth as levers.

Citations, criticism and jokes

@dsfyu404ed Feb 2020 Cites it
on HN thread Gears
sigh If I don't post it someone else will. Here's the spinning levers video you've all already seen a million times: [this video]
A well-known video on how transmissions work.
@dTal Mar 2024 Cites it
on HN thread Technical Manual TM 11-410: The Homing Pigeon (1945)
I get a similar feeling looking at instructional videos from that era[0][1], or reading books like Stick and Rudder[2][3], or even the simple brilliance of the visual design of the London Underground[4]. There's a pervasive sense that despite the reams of progress that has been made in the science of human factors, simple straightforwardness is becoming an endangered species. [0] [this video] [1] [link] [2] [link] [3] [link] [4] [link]
Example of straightforward instructional videos from that era.
@2143 Jun 2026 Cites it
on HN thread Apple WWDC 2026 Livestream
I think this “awesome”, “amazing”, “super exciting” phase came much later than the moon walking era. Remember it’s been over 50 years since humans walked on the moon. Much has changed. See these old videos, where people talk in a straightforward way: Car transmission [this video] How to dial your phone [link] The dial comes to town [link] Now go watch that Apple video again and you’ll see what I’m talking about.
Example of plain, straightforward explanation from an older era.

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