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geekhack Projects => Making Stuff Together! => Topic started by: scramm on Thu, 16 May 2013, 14:21:54

Title: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Thu, 16 May 2013, 14:21:54
I want to reduce the travel distance after actuation (more than can be done with o-rings) and make the key reset faster.  The end goal is to keep the blue switches, but make it easier to hover at the actuation point, and help with double tapping.

These are the ideas I've been rolling around:

1.  Insert a second (shorter, and stronger) spring inside the existing spring that would make contact with the bottom of the stem at the actuation point.  This should help quickly decelerate the keystroke after actuation.

2.  Switch to black springs, and put a spacer below the stem, that would cause the switch to bottom out just past the actuation point.

I may end up just changing to the heavier springs first, to see if that gives the control I'm looking for on its own.  Can anyone who's done ghetto greens comment on that?  Has anyone attempted a mod like this?
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: JPG on Thu, 16 May 2013, 14:23:38
You say that using o-rings is not enough, but have your tried 3/32 thick o-rings or just 1/16 thick ones? 3/32 should get you pretty close to the actuation point.
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Thu, 16 May 2013, 14:41:20
You say that using o-rings is not enough, but have your tried 3/32 thick o-rings or just 1/16 thick ones? 3/32 should get you pretty close to the actuation point.

No I have not.  From reading i did (and some crude tests using wire insulation) it seemed like past a certain point the o-ring just prevents the cap from sliding all the way on.  The end result was a taller looser key with the same travel distance.  It seems like in order to make that work, the o-ring would have to be compressible to almost flat, so that the cap could still be seated properly.
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: Leslieann on Thu, 16 May 2013, 19:00:36
Sounds like the o-ring was installed wrong, as that is their sole purpose.
It should reduce travel and little else, it shouldn't change how the cap sits.

Beware, some caps (SP) do not really permit the use of o-rings.
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Thu, 16 May 2013, 19:57:41
If the o-ring is big enough to stop the key stem half way down, how can you ever get enough force to get the cap all the way on?  wouldn't you be relying on the spring pressure alone, since you can no longer bottom the switch out?

The only way i can see getting around that would be a thick o-ring that can be squished almost flat, so that you can still get the cap on with enough force.  Do they make ones in the 2-3 mm range that can still be flattened?
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: Leslieann on Thu, 16 May 2013, 21:47:21
Th or-ring goes on the keycap stem, not the switch stem.
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Thu, 16 May 2013, 21:59:23
Th or-ring goes on the keycap stem, not the switch stem.

Right, but the springs are so weak, that the cap doesn't slide onto the stem until the stem is bottomed out.  If you put an o-ring big enough to stop the switch stem from bottoming, how can you ever get the cap back on?
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: gnubag on Fri, 17 May 2013, 00:07:23
http://www.wasdkeyboards.com/index.php/products/keyboard-accessories-2/cherry-mx-rubber-switch-dampeners.html

this is how it goes.
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Fri, 17 May 2013, 10:24:42
There's 1.778 mm of travel post actuation on the blue switches, so to get the reduction I'm looking for I would need 3 or 4 of those on each key.

Would that still allow the cap to fit?
Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: fohat.digs on Fri, 17 May 2013, 18:31:44
There's 1.778 mm of travel post actuation on the blue switches, so to get the reduction I'm looking for I would need 3 or 4 of those on each key.

Would that still allow the cap to fit?

You might be surprised. Try 1, then 2.

It is hard to imagine that you would need or want more.

Maybe you are chasing the wrong rabbit. If you want very short travel, get a flat Apple keyboard with scissor switches.

Oh, and in answer to the actual question - it depends. Some have long stems, some short.

Title: Re: Blue Switch Mod - reduce travel after actuation
Post by: scramm on Fri, 17 May 2013, 18:57:08
Quote
You might be surprised. Try 1, then 2.

I'll try it with just one or two first.  I might be able to hover near the actuation point easier with heavier springs anyway.  I ordered some blues, clears, and blacks to mess around with different combinations.