Why o-rings don't affect key travel

[Scoox]

Contrary to popular belief, o-rings don't affect key travel unless they are elastic, in which case they affect key feel. Here is why:



Assuming an o-ring made of an inelastic material (e.g. nylon washers), you would simply end up with key caps that stand a little higher and, more importantly, an a partial mate between the shaft and the key cap, resulting in a gap as shown in the picture. Key travel, however, remains unchanged. During o-ring installation, the shaft bottoms out as usual, but the key slides onto the shaft partially because the o-ring is in the way.

If the o-ring is made of an elastic material such as rubber or silicone, at installation time the o-ring undergoes deformation. If enough force is applied, the cap will slide further onto the shaft and the gap will be smaller, approaching, but not equalling, 100% mating. Stacked o-rings will simply reduce the quality of the mate, resulting in wobble and mush.

So, the bottom line is that o-rings are effective at reducing noise but not at reducing key travel. The most effective solution would be to take apart the switch and insert a piece of hard material between the bottom of the shaft and the bottom shell—if that's even possible.

[chyros]

Do you have an example of o-rings that are NOT elastic?

[vegs]

So, the bottom line is that o-rings are effective at reducing noise but not at reducing key travel. The most effective solution would be to take apart the switch and insert a piece of hard material between the bottom of the shaft and the bottom shell—if that's even possible.

Except that o-rings typically ARE elastic, and DO reduce key travel?

And yes that is also a silencing trick - putting a small ball of some sort of soft material in the bottom of the shaft. Also this technique affects keytravel.

[Scoox]

And yes that is also a silencing trick - putting a small ball of some sort of soft material in the bottom of the shaft. Also this technique affects keytravel.

So it's been done before? Is there a name for this trick? I couldn't find anything.with pics or videos, if you guys have any I'd be interested. I wonder how difficult it is with plate-mounted keys. Thanks

[funderburker]

Contrary to popular belief, o-rings don't affect key travel unless they are elastic, in which case they affect key feel. Here is why:

(Attachment Link)

Assuming an o-ring made of an inelastic material (e.g. nylon washers), you would simply end up with key caps that stand a little higher and, more importantly, an a partial mate between the shaft and the key cap, resulting in a gap as shown in the picture. Key travel, however, remains unchanged. During o-ring installation, the shaft bottoms out as usual, but the key slides onto the shaft partially because the o-ring is in the way.

If the o-ring is made of an elastic material such as rubber or silicone, at installation time the o-ring undergoes deformation. If enough force is applied, the cap will slide further onto the shaft and the gap will be smaller, approaching, but not equalling, 100% mating. Stacked o-rings will simply reduce the quality of the mate, resulting in wobble and mush.

So, the bottom line is that o-rings are effective at reducing noise but not at reducing key travel. The most effective solution would be to take apart the switch and insert a piece of hard material between the bottom of the shaft and the bottom shell—if that's even possible.

Gotta agree, most o-rings you'd find would be made of an elastic material. But I gotta ask what you wanted to state with this post? You're looking to get reduced key travel on your keyboard? Or it's just a shower thought? Don't want to come off harsh or anything, just interested in the reason you've made this mildly scientific post.

[swedishpiehole]

Thanks for sharing this. It's cool to have a cutaway view of keycaps with and without o-rings.

[zslane]

Contrary to popular belief, o-rings don't affect key travel unless they are elastic...

If o-rings worked as shown, then they also wouldn't perform the function they are intended for which is to prevent the slider from hitting the bottom of the housing and making its usual bottom-out clack.

[Findecanor]

If o-rings worked as shown, then they also wouldn't perform the function they are intended for which is to prevent the slider from hitting the bottom of the housing and making its usual bottom-out clack.

Precisely!

When you install an O-ring and press down the key, the O-ring becomes compressed and you are able press the slider down further.

The figures are incorrect (for most keycaps: Gateron/EnjoyPBT dished caps excluded) in that it shows no space in-between the switch housing and the keycap: there is. An uncompressed O-ring is just a little bit thicker than the gap is wide. This means that the O-ring would not have to compress to nothing if you press the key all the way down.

[swedishpiehole]

There are 2 ways in which a key press causes a clack (aside from any rattle in the switch itself): the slider hitting the bottom of the housing, and the inside of the keycap hitting the top of the housing.
O-rings, as shown by the drawings, don't prevent the slider from hitting the bottom of the housing. They prevent the switch housing from making contact with the inside top of the keycap.
Little silicone balls, which can be inserted into the area where the slider touches the bottom of the casing, silence both of these sources of clack, but they reduce key travel.
Both o-rings and silicone balls affect key feel because they add mushiness.

[swedishpiehole]

The figures are incorrect (for most keycaps: Gateron/EnjoyPBT dished caps excluded) in that it shows no space in-between the switch housing and the keycap: there is. An uncompressed O-ring is just a little bit thicker than the gap is wide. This means that the O-ring would not have to compress to nothing if you press the key all the way down.
[/quote]

The space you are referring to is created by the cross-shaped plastic pieces that protrude downwards. When you press a key, these pieces make contact with the switch housing. An o-ring prevents that, although often the difference in sound is negligible because the sound of the slider hitting the bottom is still audible. I have never found that o-rings reduce sound enough to be useful.

[Findecanor]

The space you are referring to is created by the cross-shaped plastic pieces that protrude downwards.

I refer to the vertical gap between the cross-shaped plastic pieces and the top housing when key bottoms. Because there is a gap, the O-ring does not get compressed that much when you insert the keycap, and that allows the key to be pressed down further onto the switch stem.

Signature Plastics' DCS, DSA and SA profile keycap don't have the cross-shaped plastic pieces (can't be used with O-ring unless you use many of them) and they still clack as much as Cherry profile keycaps.

I use orthodontic dental bands (very thin O-rings) for damping Cherry-profile keycaps. If I put one of these inside an OEM-profile keycap, it is thinner than the gap and does no damping at all.

[ddot]

And yes that is also a silencing trick - putting a small ball of some sort of soft material in the bottom of the shaft. Also this technique affects keytravel.

So it's been done before? Is there a name for this trick? I couldn't find anything.with pics or videos, if you guys have any I'd be interested. I wonder how difficult it is with plate-mounted keys. Thanks

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https://geekhack.org/index.php?topic=50632.0