OKI HMB-35957U-22 Oki Tactile Gourd Spring

[seebart]

Several DT users have looked at these keyboards, aside from that I had no idea what to expect.

Apart from the nice dye-sublimination keycaps the keyboard is quite mediocre, the case flexes and makes various squeaky noises when force is applied.

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The one thing that makes this interesting is the Oki Tactile Gourd Spring switch. I estimate the keyweight to be 30-35g at most. Keytravel is quite smooth with a refined & discrete click towards bottoming out. The keyfeel is very uniform across the keyboard which is generally a good sign.

wiki/Oki_Tactile_Gourd_Spring

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Technically interesting about this switch is that OKI designed a spring on membrane switch with only two parts in motion. In this case there is little friction in form of the keycap moving down the barrel and the spring being pushed down;

less parts in motion = less friction = smoother switch.

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Notice how OKI used plastic hinges / clips to fixate the membranes, quite a servicable solution compared to bolts and rivets.

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AT/XT switch, always a welcome sight in our times!

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Profile, keycaps and stabilizer:

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[Chyros]

Nice post, nice teardown! They are definitely nice switches, a bit of an undiscovered gem.

[Elrick]

Could these keyboards be the fore runner of our Topre based keyboards today?

[Chyros]

Could these keyboards be the fore runner of our Topre based keyboards today?

Brother's dome and foil keyboards are probably a better Topre forerunner than these are. They're known as Prototopre colloquially.

[002]

Yeah, I don't think they are related either. The spring bears a slight resemblance to the conic spring used by Topre, but the implementation and function is totally different, and there's never been any reason to believe they are related.

Nice one, seebart. The caps look very nice -- and on the mods they seem to have a top and bottom bulge that's a bit like that seen on Topre Hi-Pro spherical caps.

[drevyek]

Love these switches. Since seeing Chryros' video on it, I have such a desire to try them. Too bad they are in the BAE + 1u backspace layout. This is the sort of switch that would be very interesting to see a modern board of.

[seebart]

Thanks guys, these do not feel like Topre since they lack a dome. The spring is quiet (compared to Model M) and the feel is unspectacular yet nice.

...and on the mods they seem to have a top and bottom bulge that's a bit like that seen on Topre Hi-Pro spherical caps.

Yes quite noticable on the numpad enter:

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Love these switches. Since seeing Chryros' video on it, I have such a desire to try them. Too bad they are in the BAE + 1u backspace layout. This is the sort of switch that would be very interesting to see a modern board of.

With some patience you'll be able to find some, that's right you will have to adapt to the layout...I've been using it one day now it's manageable although not my favorite setup layout wise.

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Same keyboard:

https://www.youtube.com/watch?v=e8r8mgJrzTM

https://www.youtube.com/watch?v=9U_6b5r0oxA

[leetuser]

I have one of these and I thought the board came in a yellow color rather than being yellowed because my entire board is uniform in color even on the inside. These pictures lead to me to believe this plastic yellowed for some other reason considering how much whiter and blotchy these pictures look. I just love these switches. If these were produced longer and Oki improved on their design a little longer, these really could have evolved into great switches.