IBM Selectric Typewriter & its digital to analogue converter
Why Hacker News recommends it
HN commenters recommend it whenever the Selectric comes up, as a short, excellent explanation of its internals.
What it is
Bill Hammack of engineerguy uses slow motion video to show how the IBM Selectric typewriter works. He focuses on its fully mechanical digital-to-analog converter, which turns key presses into rotation of the type ball.
Recommended by 4 HN commenters across 5 different months, 2016 to 2025.
What Hacker News said
Strong rec voxadam · 2023-04 · on “DIY IBM Selectric type balls give ’60s typewriters new life (and Comic Sans)”
The Selectric is a fascinating machine. I highly recommend watching "IBM Selectric Typewriter & its digital to analogue converter"[0] by The Engineer Guy. [0] [this video]
Recommends dghughes · 2016-06 · on “Xerox Alto Restoration Part 2: Firing up the monitor [video]”
You may enjoy Bill Hammack's video "IBM Selectric Typewriter & its digital to analogue converter" [this video]
Recommends djmips · 2023-03 · on “Mechanical aircraft weight and balance computer using whippletrees”
You might enjoy these. IBM Selectric Typewriter & its digital to analogue converter [this video] The Whiffletree: A mechanical digital-to-analog converter [LINK]
Recommends golem14 · 2023-06 · on “How to make your own Selectric Typeballs”
To deepen the wonder, I'd be interested to see the longevity per material (PLA/Nylon/metal/...). I'd expect a lot of trial and error to deal with shrinkage and the probably high precision needed by the Selectric. But this is a great repository, thanks a lot! P.S. excellent short video by Bill Hammack on the Selectric internals: [this video]
Recommends voxadam · 2025-09 · on “Comic Sans typeball designed to work with the IBM Selectric typewriters”
Bill Hammack (engineerguy) has an excellent video on the IBM Selectric titled IBM Selectric Typewriter & its digital to analogue converter .[1] [1] [this video]
Cites hwillis · 2018-01 · on “Operation Gunman – how the Soviets bugged IBM typewriters (2015)”
As in, were they fast enough to be used with other layouts? Yeah, but this was back when letters were dictated- secretaries didn't go switching to dvorak. Any typewriter could technically use any layout, since you'd just have to swap out the characters. The biggest advantage of the selectric was that you could swap out the ball to get different characters or fonts. The ability to get italics was a pretty big deal. Here's Bill Hammond talking about them: [this video]
Cites pas · 2018-05 · on “Will Kubernetes Collapse Under the Weight of Its Complexity?”
A distributed system will never be as intuitive as MS Word, which is basically the digitized version of stone tables, or papyrus, or whatever thousands of years old thing we are already familiar with. Or just remain a bit more strict and look at typewriters. Word is a typewriter. People look at typewriters and sort of understand them after pushing one-two buttons. Yes, there are hidden gems and details and a long road from mechanical typewriters to Word and laser printers (e.g. [this video] ), but people are a lot more intuitive about these pieces of hardware and software, because they are simply updates on existing tech. Distributed systems is a new, and hitherto an explicitly unknown concept fo
Cites chiph · 2020-05 · on “A 1973 IBM Selectric typeball recorded dancers' body movements”
One of the interesting things about the Selectric is that it contains a mechanical digital-to-analog converter .. a Whiffletree mechanism. [this video]