Keyboard Springs for HHKB Pro 2

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Hypersphere

03 Apr 2014, 23:45

Does anyone know where I could get springs that match the characteristics of the spring found under the spacebar of the HHKB Pro2?
Spoiler:
hhkb-spring-spacebar.jpg
hhkb-spring-spacebar.jpg (312 KiB) Viewed 2522 times
According to my measurements, the characteristics are:

height = 10.0 mm
outer diam = 11.5 mm
inner diam = 10.9 mm
wire thickness = 0.30 mm
full compression height = 0.89 mm
number of coils = 4
force required for full compression = 15 grams @ 1 x g

The spring is flat on top and bottom.

Might such springs be harvested from old keyboards? I think there were BTC boards with foam/foil switches that used springs under the keycaps, and I think the Commodore 64 keyboard used a Mitsumi switch with an external spring that might be suitable.

Other suggestions welcome!

User avatar
Muirium
µ

03 Apr 2014, 23:54

What do you need them for? Yours gone missing, or are you up to something cunning?

User avatar
Hypersphere

03 Apr 2014, 23:57

Up to something. Don't know yet if it will turn out to be clever or foolish.

User avatar
Muirium
µ

04 Apr 2014, 00:00

My money's on Model F style heavy spacebar HHKB mod! Nothing gives your thumbs a workout like a little hard labour on the old XT.

User avatar
Hypersphere

04 Apr 2014, 01:40

Muirium wrote:My money's on Model F style heavy spacebar HHKB mod! Nothing gives your thumbs a workout like a little hard labour on the old XT.
Yes, I was thinking of something like this:
Spoiler:
spring.jpg
spring.jpg (94.35 KiB) Viewed 2498 times
http://www.reefcentral.com/forums/showt ... ?t=1719948

User avatar
Hypersphere

04 Apr 2014, 16:08

Muirium wrote:What do you need them for? Yours gone missing, or are you up to something cunning?
Actually, what I have in mind is an attempt to increase the force required for key presses on the HHKB Pro 2 by slipping a light spring -- such as the one found under the spacebar -- over the slider of each key.

I am not sure how the spring in the spacebar contributes to the actuation force curve. Given that the spacebar is the largest and presumably the heaviest of keycaps on the board, the main purpose of the spring might be to assist with its upward return. However, the spring would also necessarily add to the force required to press the switch. What I am hoping to achieve is a simple way to convert the 45g HHKB Pro 2 to a heavier version, e.g., 55g.

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