deskthority

(Note: I originally posted this in the geekhack 'keycaps' subforum https://geekhack.org/index.php?topic=68550.0;topicseen and commenters may want to read that thread / respond over there.

I have no idea where it belongs over here: keyboards? reviews? photos? workshop? Someone can feel free to move it if this is the wrong spot. Mainly I’m reposting it here at Deskthority for the benefit of folks who don’t read both forums.)

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Before the most recent Bay Area keyboard meetup, I made a bunch of little one-column steel keyboard plates with sides/legs made from 1/4" transparent acrylic.

They’re pretty nice for demonstrating various keycap profiles, because you can see exactly what’s happening from the side, and compare a few of them by holding them next to each other in your hands, which is hard to do with full keyboards.

Anyway, I thought I’d post some pictures here. First a whole bunch in one shot:



Approximation of a manual typewriter, rows in stairsteps:


Simple flat keycap profile (in this case from an Apple //c); DSA is somewhat similar though this one has cylindrical tops:


What you get when you try to make something typewriter-like using a flat plate (in this case, some spherical-ish Alps doubleshots from the mid-80s). Personally I think this is a big improvement over the simple flat version, but still not ideal:


Sculpted spherical doubleshots from a Canon typewriter; these are a straight-switch approximation of the profile from a Selectric / Beam Spring / Honeywell / etc. Lots of keyboards in the 70s and early 80s used a profile like this, sometimes on switches with straight stems, like this, and other times on switches with tilted stems.


When you use keycaps designed for angled-stem switches (Signature Plastics SA = “spherical angled” correction: actually stands for “spherical all-rows”, though I still maintain that it makes more sense with angled than straight stems), then you get something like this. As I’ve described elsewhere, I think this is a mistake. Notice that there’s no real height step between the far side of one keycap and the near side of the next one, as you reach for further-away rows, and as a result your finger doesn’t get clearance to press the further key down without colliding with the closer keycap (Compare to the picture above):


IBM (and Honeywell rubber domes, and some other boards) tried to make it cheaper to get a sculpted profile while using uniform keycaps by using a bent plate. Here’s my Model F approximation using standard cylindrical Alps caps, home row. This is not quite right (I need to go cut a V2 of the acrylic sides, and might need to use bottom-row caps instead), and one switch is also not seated properly in the plate in my picture, but it gives the idea:


And now a few sculpted cylindrical profiles, first ones that double-up the number and F rows (making it necessary to keep some space between those rows to avoid the finger collision problem):

Cherry doubleshots:


Cylindrical Alps dyesubs:


Unknown-producer doubleshots from a Laser keyboard (keyboard used MX-mount SMK switches):


Now some profiles where I have an extra-tall F-row keycap:

Alps dyesubs from an Apple Extended Keyboard II (notice the F row keys use switches mounted sideways, to reduce front-to-back wobble from being so tall):


Tai-Hao doubleshots (from an MX-mount Futaba board):


Signature Plastics DCS:


If anyone has a keyboard with an F row directly adjacent to the number row, I highly recommend using a keycap profile with an extra-tall F row.

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The basic idea was to make a physical version of this chart:

Awesome display. Helps me visualize these profiles much better than I've been able to int the published literature.

Very cool! Nice work, jacobolus

Nice and a lot of work you put into these displays! I already saw some of your images and explanations regarding keycap profiles. I like sculptured or curved switch plates most, and DSA for example just feels wrong - but also because i am not using it as much as sculpted profiles. But i think it is really only like what you use most... For example on the notebook you don't have that much choice.

That's a great way of presenting the different profiles, thanks for making these and presenting them here!

Maybe it would be nice to include (as a daunting example ?) the generally most popular profile of 2015 by far, which is the flat scissor switch chiclet board.

I actually bought a broken Apple aluminum keyboard, which I want to figure out how to cut a column out of (there's a full column of 1x1 size keys in the numpad area). I probably won’t get around to it for a month or two though.

Nice work indeed. And thanks for posting it here too, I can't follow both DT and GH. I'll bookmark this and link to your pictures whenever people are asking about profiles.

I get what you're saying about SA, but I don't feel it in use. The way I type — floating style, hands high — doesn't seem to expose the issue. I much prefer SA over DSA, or indeed "all row 3" flat SA. Flat rows mean reaching more, especially for the top of the board.


vs.

or this


By the way, some Honeywell Hall effect boards used uniform profiled sphericals on angled stems. All the caps on mine are "row 3" in SP/SA speak. But angled by the switch stems. A bit better than flat DSA, perhaps, but no substitute for real row profiles.


http://deskthority.net/photos-f62/a-hon ... t6296.html

Crystal clear demo, thanks Jacobulus !

Nice work, jacobolus. Great demo.

Okay, more pics:

Partly fixed buckling spring approximation:


“OEM” profile (these are backlight-friendly paint+laser caps from one of those MX “gamer” boards):


Signature Plastics DSA:


Uniform row 4, Signature Plastics SA:


Uniform row 1 flipped, SA:


Uniform low cylindrical (these are pad-printed ABS from a Bondwell laptop with MX blue switches):


Apple ADB Keyboard (used with the Apple IIGS, part number 658-4081):

Muirium wrote: ↑I get what you're saying about SA, but I don't feel it in use. The way I type — floating style, hands high — doesn't seem to expose the issue. I much prefer SA over DSA, or indeed "all row 3" flat SA. Flat rows mean reaching more, especially for the top of the board.

Basically, if you get a sufficient height step (1.5mm or more) from the front of one key to the back of the key before it, then you can press the key down with an almost entirely flat finger. Once you eliminate that step, you can no longer press the key down with a flat finger, and you need to move your hand a bit to reach the key with a curved finger. Even when moving the hand is required (like on an F row), having the far-away keys be a bit higher up / taller makes them easier to reach.

It’s certainly *possible* to type on entirely flat keys with no height step from one to the next, or even with perfectly flat 19x19mm keytops with no space between them. But that requires much higher precision keystrokes than if you have smaller keytops with a gap between, a concave top shape for the finger to rest in, and a step from row to row. (Precisely what angle and height for each row and what keytop size and shape is best is open for debate.)

I agree with you that SA keycaps are nicer than uniform DSA or uniform SA-row-3, but I actually somewhat prefer a uniform “stepped” profile like your pictured Honeywell board instead of Topre HiPro caps or sculpted SA on MX switches, both of which are IMO suboptimal. The big problem with the uniform stepped shape is that the bottom row (ZXCV row) and the number and F-key rows are harder than necessary to reach.

I really like typing on a board using sculptured (e.g. the regular cylindrical ones) caps where I’ve shifted all the further-away caps down one row (so using F row caps for number row, number row caps for QWER row, QWER row caps for ASDF row, skipping the standard ASDF row caps, and leaving the bottom two rows as is):


For me it’s a noticeable improvement over the standard profile.

In the diagram below, purple = standard DCS, green = the profile from the picture above, black = close to my ideal for a standard-layout keyboard:

Maybe. I just don't seem to feel it with the angle my hands and arms approach the board from.

Good point about smaller tops being nice. I like little Topre caps and the similar NMBs on my space invader board. Didn't think I would, but they make a nice change from my rounder IBM cylindricals for sure.

I haven't commented yet, but this is a great work jacobolus, thanks for sharing.

Just for the sake of correctness, the meaning of SA jacobolus is suggesting is not correct.

SA stands for "Spherical All" (not Spherical Angled) because originally SA was not sculpted, keys were All on the same row (row 3). Only later SP made the other molds and now SA is an angled profile and referenced as "Sculptured SA".

DCS stands for DIN standard, Cylindrical touch, Sculpted profile.

DSA stands for DIN standard, Spherical touch, All rows.

Cool. Any idea what SS stood for?

Should be Spherical touch, Sculptured (or Sculpted, never remember which one...)

matt3o wrote: ↑Just for the sake of correctness, the meaning of SA jacobolus is suggesting is not correct.

Note, Daniel Beardsmore wrote to SP to figure this out (as far as I know he’s the first person to get the full story), and put it on the geekhack thread where I was speculating about this topic, after my posts above.

However, I still maintain that SA profile only really makes sense on switches with tilted stems (I’d be very interested go back in time to the 80s when SP’s predecessor Comptec was actually first designing these keycap profiles, to find out which keyboards they were first made for).

Daniel’s post dated Tue, 10 February 2015, 00:20:31 quotes Melissa of SP:

Melissa Petersen wrote: The first keycap family produced by Signature Plastics’ previous company, Comptec Inc., was the SA family. These keys had a Spherical touch area and the same profile for All rows.

A few years later the company began producing the SS family which also had a Spherical touch area but with a Sculptured profile i.e. each row had a different keycap angle giving the keyboard a curved look. Because of the limited number of shapes that were tooled, this tooling has been retired and is no longer available for production.

In the mid 80’s an attempt was made to standardize keycaps to a ‘DIN Standard’. DIN stands for “Deutsches Institut für Normung”, meaning "German institute for standardization". This resulted in a new high profile family being produced, the DSS family, which was a DIN standard, Spherical touch, Sculptured key family. This family profile was never very popular and was quickly retired. A short time later the SA family was re-tooled to produce a sculptured look. The keycap family name didn’t change, but it was simply referred to as sculptured SA.

The fourth family tooled was the low profile DSA family. These keys met the DIN standard, had a Spherical touch area, and the same low profile look for All rows.

The DCS family followed shortly. These keys conformed to the DIN standard, had a Cylindrical touch surface, and a Sculptured profile.

The latest keycap family, introduced by Signature Plastics in 2015, is the G20 family. These keys were designed with the gaming community in mind. They have a flat touch area that is wider than standard keycaps, resulting is a smaller gap and easier transition between adjacent keys. These keycaps have the same angle for all rows, similar to the DCS R2 profile.

so long and thanks for all the keycaps!

Also, for what it’s worth, just judging from diagrams, I think DSS profile is the best one SP ever made. Oh well.



I really like these Canon typewriter caps, which are a bit taller but otherwise similar to DSS:

jacobolus wrote: ↑Also, for what it’s worth, just judging from diagrams, I think DSS profile is the best one SP ever made. Oh well.

agreed!

What keycap profile on a flat plate would be the closest approximation to buckling springs on a curved or bent plate?

Well, none are quite the same, because the bent plate changes the axis of the switches on different rows. Personally my opinion is that the bent plate is an inferior (but slightly cheaper) construction, compared to having different keycap shapes on different rows. On a flat plate, just choose any sculpted profile, such as Cherry/Alps/“OEM”/DCS.

great work jacobolus, thanks.