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Key Cap profiles: Topre Realforce HiPro vs 10 Old-School Keyboards
Posted: 09 Dec 2015, 01:51
by snuci
Posted: 09 Dec 2015, 17:25
by Halvar
Great documentation! The beam spring switches have a tilted mount though, and probably some of the other keyboards, too, so the profile on the actual board will be different.
I took this photo of a 3278 once that shows the effect:

Posted: 09 Dec 2015, 19:14
by XMIT
This is a great start. I've been meaning to get to something like this for ages.
Future improvements:
- I'd like to quantify the size and shape of the spherical area on the top of the key caps. Some, like Topre, are squared at the edges, and others are true sphericals.
- For boards that use tilted key switch stems, it would be good to get a profile both with key caps flat on the desk and key caps mounted on a board (or tilted at the same angle as their stems).
- Long shot: I'd love to see accurate 3D models of all of these caps, or CAD drawings based on precise dimensions.
This is certainly missing Selectric typewriter and/or later model IBM beam spring keyboards.
But all great work must start somewhere and this is a great start!
Posted: 09 Dec 2015, 19:23
by klikkyklik
Holy cow, those vintage Alps keys are TALL! Wow!
Cool stuff, Snuci!
Posted: 09 Dec 2015, 19:36
by SL89
Do any of these boards have curved backplanes?
Posted: 10 Dec 2015, 00:12
by snuci
None of the keyboards have a curved back plate but some do have angled key stems. It's sort of easy to see from the "arc". If it's fluid, they are not angled. If it is jagged like the TRS-80, the key stems are angled. Unfortunately, you can't really check key cap height if the stems are angled like the picture you included Halvar.
Here are some pictures of the key caps. Sorry but I don't have the Topre Realforce HiPro at home for the "photo shoot" (it's my work keyboard). As you will see, these key caps are all the "A" key. The pointy end of the "A" is pointing to the wall when you can't see the key cap symbol.
Order from left to right:
1. IBM 5100
2. IBM 5110
3. Datapoint 1500
4. TRS-80 Model 1
5. Xerox 820-II
6. Alps AKB-3420
7. Nabu PC
8. Vintage Unknown Alps
9. Vintage Unknown SMK
10. Home-made Micro Switch

- Key caps front
- Key caps front.jpg (153.28 KiB) Viewed 2643 times

- Key caps top
- Key caps top.jpg (168.87 KiB) Viewed 2643 times

- Key caps bottom
- Key caps bottom A down.jpg (201.57 KiB) Viewed 2643 times

- Key caps bottom 30 degree angle
- Key caps bottom 30 degrees.jpg (241.18 KiB) Viewed 2643 times

- Key caps bottom 60 degree angle
- Key caps bottom 60 degrees.jpg (222.8 KiB) Viewed 2643 times