IBM Selectric Typewriter & its digital to analogue converter

Using slow motion video Bill Hammack, the engineer guy, shows how
IBM's revolutionary "golf ball" typewriter works. He describes the
marvelous completely mechanical digital-to-analogue converter that
translates the discrete impulse of the keys to the rotation of the
type element. (This is the typewriter featured on the television series Mad Men.)

Category:

Science & Technology

Tags:

• Mad Men
• d-to-a conversion
• whiffletree

[Meddlmoe]

How do the positions of 3 tabs encode 22 posistions?

[engineerguyvideo]

@Meddlmoe . I should have highlighted one more of those levers in blue. The far right one hooked to the cable and so transfers the "pulls", but the lever second from the right is part of the whiffletree tabs. That would give 2x2x2x2 which is 16 and is more than enough for 11 rows. The shift lever is not shown in the drawing. Note that is is a TOTAL of 22 rows ... 11 on each side. So if the ball is set for lower case you need 11 positions; if it is in upper case 11 positions. Does this help?

[SpecialtyLEDSonline]

@engineerguyvideo Fascinating! Hard to believe that this thing even works, and works as well as it does!

One thing that has ALWAYS fascinated me is how we design and machine these small parts and devices to the exact level of precision necessary for these devices to work - repeatedly.

Have you ever considered making a "measurements" engineering video? I would it! I know today that smaller measurements are made possible by using lasers and sensors, but what were the standards for back then?

[engineerguyvideo]

@SpecialtyLEDSonline Good suggestions. Let me think about this. Year ago I recall someone saying to me that whenever you wanted to make a measurement precise you converted "it" to frequency ......

[felipeceglia]

what is the background music?

[engineerguyvideo]

@felipeceglia It is music that we purchased for this ... it designed to be used like the segues and background music in desperate housewives, six feet under, etc

[BraunMannn]

@ww2315 Dear vvvv., It sounds like you have been to the Science Museum in London. They have lots of thing's development on display. Including a display of the CD and its ancient (AT&T) Bell systems customer billing punch card machine; and even back further; (all on the third floor) . Heaps of things to see, better than 'being old' and having seen it all first hand; or You-Tube, even. . . Cheers. from, del-boy.

[JoaoKost]

fringe



[kahvac]

I still remember my first Selectric. Nothing like it ever existed before. It was very advanced for it's time. Thanks for taking the time to explain this incredible machine !

[jix177]

Very well explained! Thanks.

[massacreman3000]

This kind of things makes me wonder about all amazing things of yesteryear.

Even mechanical typewriters are awesome to watch in action.

[ww2315]

Tilting and rotating printheads go back as far as the late 1800's. IBM's machine was not a new concept..

[appleip]

i got a Selectric composer that is a amazing peace of equipment

[Xerox6085I]

The funny thing is, the IBM selectric did not work when it went into production and it was "fixed: by field service technicians...

[HB45175]

Anyone else think that typed letters look nicer than printed ones? I think it's because a typed letter isn't flat like a printed one, you can feel a bit of texture. And printed letters feel very artificial and computerlike.

[jjovereats]

Should I create a non-electric version of this?