Recreating the Lisp keyboard (10 years later)

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15 Jan 2021, 18:45

Hi guys! This is lispnick, my first post here. About a couple years ago I got a crazy idea of recreating Symbolics 365407 Rev A. From what I have read in the forum, I was not the first person with such ambition. At first, I just wanted to get the original for my regular work and had absolutely no intention to start some kind of home-based keyboard manufacturing. That all changed when I finally got one of those from eBay and held it in my hands—man that was a beauty! I hacked TMK and Hans Hübner's firmware together and started using the board for my job.

Of course, the story could have ended here. Thankfully, I was curious if one can build a keyboard like that and what it takes. After doing my research, I have devised a plan of making a close replica of the keyboard meeting two important criteria. First, the same external dimensions of the case, the same key layout, and key profile in order to preserve its original ergonomy. Second, the ability to reproduce the keyboard using contemporary components either custom made or outsourced (with everything over-engineered to the max, of course). Piece of cake, right? I have soon realized that this ingenious plan would make production of a single keyboard immensly expensive, so I changed my plan to produce ten keyboards, reducing the cost per keyboard. I had continued with this plan for some time until I realized I was no longer interested in my regular job but in recreating Symbolics 365407. So I took the only course of action possible—I quit my job and started a company. After a year of intensive development, buying my own CNC, turning my house into a production facility, and doing other crazy stunts, I have finally decided to reveal the result to the public and this is perhaps the best place to do it.

So, without further ado:


Comparison with the old folks and typing demo:
Some technical details: The keyboard is designed as Alps/Matias compatible. The typing demo features keyboard with SKCM salmons. I started to use pet name ‘Keymacs’ for the first prototype (with the obvious hidden reference to Symbolics / Keyboard / Emacs / whatever) and decided to use it for the final product as well. Of course, it would not be a proper piece of machinery without a sufficiently complex model number—so here it is: Keymacs A620N-88, meaning Alps-compatible, 6x20 units large, (Symbolics) new-style layout with 88 keys. Cryptic enough? You make the judgment.

I had three good reasons for choosing Alps. First, I have a stash of vintage SKCL/SKCM switches sufficient to make 15±2 keyboards. Second, I love Alps. Third, I want to be able to use some decent contemporary switches and I personally like (modded) Matias switches.

In terms of the external appearance of the keyboard, I tried to match the profile of the case and the keys to the original as closely as possible (the whole beast went through a high resolution 3d scanner). At the same time, I wanted to create a set of keycaps that are nice, big, and heavy. I always liked those on Honeywell and IBM keyboards. So in order to preserve the profile of the keyboard, I had to put the mount plate lower in the case. The bottom part of the case is 3mm thick, however, in the spacebar row I had to make the case thinner in order to fit the switches in the case.

The keycaps are polyurethane-cast because injection molding was outside of my budget. Creating the initial blank set of keys was relatively easy—I designed the model and machined a set of matrices used to create silicone forms. The real challenge was the legend. I dismissed laser engraving after I found out that lasering on polyurethane releases some no-good fumes including CO and HCN (I tried it once. I did not inhale.) and, more importantly, a proper keycap set has to be double-shot molded, right? I experimented with 3d printed inserts but this did not turn very well. The issues were precision, repeatibilty, and the speed and cost of the process. It would be a fine way to create a keycap if you want a single replacement for your vintage keyboard but definitely not a method for producing entire keyset each week. At that point I bought a CNC and decided to individualy machine a matrix for each insert. It took me three months, 8 hours a day, to complete the basic set (clearly, I rank 10 out of 10 on the General Scale of Keyboard Insanity). Here is a detail of the letter Z:


Profile comparison (ZXCV-row):


The dish and its curvature is the same as in Symbolics 365407 (Rev. C), the key is bigger because it sits lower in the case:


And of course, it is a heavy monster:


The font was designed as a blend between the old-style Symbolics keyboard and IBM 5251:


In addition to the Symbolics-style legend including the ‘brackets above parentheses’ keys, each keycap set contains the standard keys for those who want something more traditional, here are some possible configurations:


I plan to make some more videos from the production to describe the proces of creating the keycaps from the beginning to the final over-molding.

Final notes (this post is too long already): I have also created an on-line keymap editor that can be used to dump sources for QMK. When I started experimenting with various key bindings, I missed a tool that allows me to make changes quickly and on a higher level of abstraction than just ‘assign keycode to key’. This is, of course, still possible to do in the editor but in addition it allows to define the bindings by activating ‘logical layers’ (e.g. turn-on standard QWERTY) and using acyclic inheritance between layers (e.g. make default binding for each key on layer X based on its definition in layer Y), it is shown in this super-fast feature overview:
All these extra features are translated in plain QMK code. In addition, I provided definitions of the extra Symbolics keys like ‘brackets above parentheses’. I initially implemented those in a similar way as the ‘grave escape’ in QMK, however, there were same issues with ‘key unshifting’ and interaction with other (possibly shifted) keys, so I decided to send all keycodes on key press and… too much detail, eh? Anyway, if you are a serious Emacs addict, you work in X11, and know how to use xmodmap, this clearly makes your day: Finally a keyboard when you can use quadruple buckies (Control-Meta-Super-Hyper). Actually, you can use more! Alt and Meta can be defined as independent modifiers in X11 and, better yet, the Symbol key can be bound to a Mode_switch,… see excerpt from my ~/.Xmodmap file:

Code: Select all

!! clear all modifier keys
clear shift 
clear lock
clear control
clear mod1
clear mod2
clear mod3
clear mod4
clear mod5 

!! set modifiers keys
add shift = Shift_L Shift_R
add control = Control_L Control_R
add mod1 = Meta_L Meta_R
add mod2 = Super_L Super_R
add mod3 = Hyper_L Hyper_R
add mod4 = Alt_L Alt_R

!! Symbol as Mode_switch (here 135 depends on the keycode assigned to the key)
keycode 135 = Mode_switch

!! standard letters + Greek alphabet
keycode  43 = h H Greek_eta Greek_ETA
keycode  44 = j J Greek_xi Greek_XI
keycode  45 = k K Greek_kappa Greek_KAPPA
keycode  46 = l L Greek_lambda Greek_LAMBDA
This allows you to make key combinations like Hyper-Super-Alt-Meta-Control-Shift-Symbol-A on a single keyboard which Emacs properly registers—pretty neat.

More details can be found at

I welcome comments and suggestions for (future) improvements. If anyone is interested, I have material to build a first batch of 50 keyboards, including ‘exclusive kits’ on SKCM Brown (2 pcs.), SKCM Blue (3 pcs.), SKCM Orange (3 pcs.), SKCM Salmon (3 pcs.), SKCL Green (5 pcs.), and SKCMBB Cream (1 pc.) Alps. A single keyboard can be completed in a week (the most time-consuming part is making of the keycaps and related maintenance of the moulds, blank keysets are done faster).

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15 Jan 2021, 18:59

Mind-bendingly impressive stuff! 10/10 keyboard insanity for sure.


15 Jan 2021, 21:02

Very cool project!
Any change you would be interested in recreating the space cadet as well?

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15 Jan 2021, 21:12

arcticfox wrote:
15 Jan 2021, 21:02
Very cool project!
Any change you would be interested in recreating the space cadet as well?

Also, this is insane. I can't afford one, but the effort and passion that went into this. Incredible!

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Gotta start somewhere

15 Jan 2021, 21:20

Man this is hecking awesome! Definitely pricey, but I would say that is well justified given the amount of work you put into this and the quality of the keyboard.

The pure amount of care that went into this project is admirable, I hope more people get interested!


15 Jan 2021, 22:09

Case, website, editor and keycaps all look great!

From the website:
Are the keycaps UV-stable?

The keycaps have been treated with anti-UV agent and are colored by UV-stable pigments which ensure long life and color stability under normal conditions, however, we advise to avoid direct sunlight and to cover the keyboard when it is not in use.
Is that a spray-on coating or resin additive? Have you noticed any texture difference with/without it? I'm curious what products you've used if you're willing to divulge that.

I've resin cast beamspring caps with MX/SKCM stems and done some basic double shot experiments, I definitely agree that chunky caps are great on SKCM :D

I didn't see a picture of the spacebar bottom, are the stabilizers similar to the original ALPS "rod" ones?
lispnick wrote:
15 Jan 2021, 18:45
I plan to make some more videos from the production to describe the proces of creating the keycaps from the beginning to the final over-molding.

Ideas for improvement/future boards:
I'd imagine a split spacebar option could be popular (split down the middle = one additional mold).
If you mix resin batches for each board you could offer any color combination for a fee, a unique selling point.
Same goes for custom legends (STEEP fee or interest checks/voting for popular choices)
Perhaps a gasket mounted plate or other case dampening options, you already have experience molding silicone and resins.

Jan Pospisil

15 Jan 2021, 22:33

O_O Someone actually made new Alps caps in this day and age?!
And they're super thick?! O____O

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15 Jan 2021, 22:34

Also any chance you will be selling keycap-sets separately?


15 Jan 2021, 23:57

Jan Pospisil wrote:
15 Jan 2021, 22:33
O_O Someone actually made new Alps caps in this day and age?!
And they're super thick?! O____O
SP have had a few runs in recent years.

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16 Jan 2021, 00:27

The dopest thing of 2021

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16 Jan 2021, 00:30

Oh man, you did God's work. Would be too much to ask for a more detailed talk about the keycap casting process?


16 Jan 2021, 00:33

This is incredible - I'll be reading, and rereading, through *all* of this and the site with interest.

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16 Jan 2021, 00:36

Also any chance of making 364000?


16 Jan 2021, 02:14

This is fantastic! How would you say the polyurethane caps sound compared to more traditional materials like ABS or PBT?

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16 Jan 2021, 04:48

PlacaFromHell wrote:
16 Jan 2021, 00:30
Oh man, you did God's work. Would be too much to ask for a more detailed talk about the keycap casting process?
I would also be super interested in this info as well. It sounds like you are making silicon molds and testing into them? If so you might be able to adapt them for use in a small injection molding machine without much trouble and that might speed up the production rate. There are kits you can bolt onto a drill press (after removing the drill) that are pretty affordable (well, closer to affordable than some of the other options)

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16 Jan 2021, 05:14

Like everyone else that has already stated the keycaps are killer and would love if they were offered separately as well.


16 Jan 2021, 07:04

Second the suggestion about a separate keycap offering.
Would be better if the keycap could be adapted for other boards, like Model F or beamspring.

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16 Jan 2021, 07:10

What an insane project... incredible.

And yes, separate keycaps would be beautiful.


16 Jan 2021, 07:33

This is amazing.

I see how much work went into the black keycaps, but is there any thought of adding legends to the gray ones, too? Getting back blockhead, bubblehead and pinhead would be fun, though maybe useless. But a large RUB OUT and a small CAPS LOCK makes a statement even today. Not a deal-breaker, though.

I guess unshifted colon (so the same stream could alternate forms and commands) is even harder to justify than unshifted parens.

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16 Jan 2021, 17:02

I only have a passing interest in the Lisp keyboards, but your dedication to this project is truly inspiring.


17 Jan 2021, 02:48

Why did you choose to go with the (in my opinion) more boring and flat looking colors of the 2nd gen Symbolics keyboard rather than the blue and gray of the space cadet? I would 100% be on board if you offered this in a space cadet color scheme!

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17 Jan 2021, 02:58

digital_matthew wrote:
16 Jan 2021, 17:02
I only have a passing interest in the Lisp keyboards, but your dedication to this project is truly inspiring.
I have no interest in LISP and I think this project is cool!

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17 Jan 2021, 20:22

Cool project and an incredible achievement!

I love the look of the Symbolics 2nd gen, to me it’s sleeker and cooler than the Space Cadet (an unpopular opinion around here, but hey).

And ballsy to choose Alps! Love that! If the price was a bit lower, I could see myself getting one. I would guess the sweet spot is somewhere around €6-700 for a partially soldered kit without switches, but I imagine that could only be done by cutting a bunch of corners and scaling up production, which — well, I can understand why that isn’t going to happen.

Congratulations on this stunning product and I wish you all the best!

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18 Jan 2021, 01:31

Thank you all for the feedback. Sorry for late response, I am recovering from my teeth surgery. :mrgreen: I will try to answer some of the questions.

First the bad news. I do not consider to make and sell keycaps separately at this point. When I realised it does not make much sense to compete with services like Massdrop in terms of the price, it came to me that I must make something exclusive, preferably in more than one way. That is why I invested time in the editor, trying to make an ecosystem around the keyboard and the keycaps are a part of that exclusivity. Maybe I will reconsider that in the future.

The good news. I definitely consider recreating Symbolics 3600 at some point and from that it is just a small step to the Space Cadet (I do not own one yet, if anyone wants to get rid of it, please contact me, I can easily be persuaded to pay an insane price). I guess this will all depend on the sales of the present model. If I will be able to get my investment back in some reasonable horizon and will be able to contribute to my household (my wife and kids really enjoy this new full-time hobby of mine but I am afraid their patience is limited), I will definitely look at that. The 3600 has much more space in the case and this could be a good opportunity to make something more universal.

Color schemes: I am a bit conservative when it comes to keycap colors and I personally like the old-style Symbolic color scheme more than the Space Cadet one, however, I would like to introduce color variations. I will probably start by making blue and green tones for the functional keys. I think this could look classy and give you a hint what kind of switch is under the hood.

Used resins: The best in my experience are Smooth-On products. I use Smooth-Cast in combination with the UVO stable pigments (1% of the mixture) and Sun Devil (1% of the mixture) as the anti-UV agent. No coating applied after demoulding. I did a non-scientific test with various pigments and resins (I left them laying 2 years behind my window) and the Smooth-Casts still look like new, no signs of degradation.

Spacebar stabilization: I went through a number of prototypes and ended up with something similar to the alps-style stabilizers. The bottom hooks are by Matias, top hooks are similar to the vintage alps (these are machined and made of POM), U-shaped stabilization bar, and a system of rails (again, machined from POM):


This is my personal tribute to Space Invaders:


Spacebar internals:


Sorry, poor photo. But I think the concept is clear: The spacebar has three stems, the middle one intended for the switch, the side stems hold Matias sliders—these slide in the jaws of the space-invader rails. The hole for the space-invader rail is a standard alps-switch hole (it is only secured with screws, I did not have the guts to machine alps-style wings), so in theory you can put an additional switch there (with or without a spring).


22 Jan 2021, 01:45

Damn, if I didn't just make a pretty big keyboard purchase/trade, I'd be all over this

Definitely intend to jump on this in the somewhat near future

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22 Jan 2021, 08:42

Impressive... Expensive but I think that the price is reasonable given the effort and exclusivity, even "cheap". I value you had the guts to go for the Alps/Matias road, given that the immense majority of the market goes cherry these days.

I cannot even believe you managed to make that "homemade" double shots. At some point you may well become rich by selling some Selectric blue sets...


22 Jan 2021, 11:00

I would consider rounding the corners of the case to be more similar to the original (but when it comes to machining I understand some things are easier said than done).

Still I think the price is fair (especially given the quality of the keycaps), considering some fairly standard custom boards are in the $700+ range these days (no idea when it became the norm, but Keymacs is way cooler than something like and probably uses a bigger chunk of metal)

If the price comes down a bit in the future I might grab one, but me being poor =/= Keymacs is too expensive, just that I can't afford it :lol:

Good luck with this, it's clearly a product of passion on the same level of the new Model F, and something I'd love to see more of.


26 Jan 2021, 06:21

Great work lispnick! I hope to see more projects like this from the keyboard community.


26 Jan 2021, 12:21

After seeing this I couldn’t help but grab one of the kits off your site. The attention to detail, the level of workmanship - it demanded that I support you! Excited to see the finished project on my desk

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21 Feb 2021, 18:03

Hi guys! I have made a quick sound comparison to give you an idea of the difference between my keycaps and the more traditional Alps-mount keycaps. I have used a subset of trapezoidal PBT keycaps that came from the IBM PC Convertible. The demo shows the results on a board that has NeKtar-lubed green alps under the hood.

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