Revealed: The Story of the IBM Model M4 family of keyboards

Hey all!

This is the story and (aiming to be) definitive article on the IBM Model M4 and M4-1 Space Saver buckling sleeves keyboards, the keyboard that came before and largely inspired the first generation of ThinkPad keyboards (the Model M6).

Well… sort of. The story is a bit more complex but everything is explained inside! This has been over a month in the making and features contributions from several awesome people! All contributions are acknowledged at the end.



Update: Along with some minor spelling and grammar improvements, I’ve added photos of a Lexmark-branded M4. Thanks to deskthority user arkanoid for offering these photos for the article!

You can go straight to it here:


Good read. Some of the details regarding the logos may not be exactly right but thank you for making this article. Here are my M4’s with a M3 number pad. The M3 Number pad has had its guts replaced with M4-1 internals so it works with the standard M4.


Glad you liked it! Though, what did you find wrong with the logos details?

The silver logo M4-1 in my picture:

The Blue logo M4 in my picture:

Upon reading the article again, I retract what I said about it being incorrect, rather the article omits Unicomp-made beige M4-1s, currently the article states “Unicomp-made black M4-1s used flat blue IBM text on black background”. I originally read this as “Unicomp-made M4-1s used flat blue IBM text on black background”


Ahh, thanks for clarifying.

Indeed, I struggled to find photos of an IBM-branded beige Unicomp M4-1, hence I omitted it. Now that I have solid evidence, I’ll add that fact to the article and go live later this week on my website’s next deployment cycle. Thanks!


I have been looking for modern re-creations of this layout and only found one. It is extremely hard to recreate with MX switches, because IBM cheated and used smaller keycaps for for the right hand cluster, allowing them to be spaced closer and creating separation where there would normally be done.

Without that extra separation it looks like this:

I don’t know if we will ever see this elegant design recreated properly.


Matcha gang!

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