What is our stance on questions pertaining to keyboard modding? Are they on topic or off topic?


Subject: Does stacking o-rings provide the same result as using a thicker o-ring?

I plan to add o-rings in my mechanical keyboard. Does stacking o-rings provide the same result as using a thicker o-ring, from the standpoint of the keyboard user?

The goal of adding o-ring is obtaining reducing key travel to be as low as possible (without having to hammer the keys for them to actuate).

For example, I could use two o-rings stacked on top of each other (1.5mm + 2.5mm) like this:

enter image description here

or directly use a 4mm o-ring.

Let's assume the o-rings have the same inner diameter, and are applied to a Cherry MX key switch. I am thinking of using 40A o-ring.

enter image description here

3 Answers 3


In the help center topic What topics can I ask about here?, we see that one of the things you can ask about is:

  • computer hardware

Keyboard modifications definitely fall under computer hardware.

There's nothing in that article that says you can't ask about such things. Therefore, as long as the question is constructive, it's good. The example one in your question here is great - it's practical and answerable.

  • well the question got closed. May 2, 2016 at 14:05
  • 2
    @FranckDernoncourt In my opinion, it shouldn't have been. It asks a question about whether two arrangements would produce the same result. I should have mentioned that it would have been nice to state more clearly what aspect you were comparing (key travel), so my misstep there. I edited your question and voted to reopen.
    – Ben N
    May 2, 2016 at 15:35
  • 1
    It has been reopened.
    – Ben N
    May 2, 2016 at 17:10

I think many of my concerns here are that its opinion based. On one hand, I think its an interesting question. On the other hand, there's just so many variables. The way a single or two o-rings act would differ. A smaller oring might stretch, and so on.

In addition, the question is unclear over what your desired end result is. Do you want to prevent bottoming out? Get a 'optimum' amount of key travel? Do you want to use these to reduce noise? In these cases your answer may vary with switch types as well. Reducing travel too much might also result in keys that don't actuate.

I don't think the issue is with the broader scope, but in that this specific case , this feels like something you're in the best position to answer.

  • Thanks for your answer. Why should the question mention the desired end result? As for the number of variables, I don't think there are that many (key switch, diameter, hardness, thickness, o-ring material), and I'm not sure whether any of them would impact the outcome. If I knew, I probably wouldn't have asked the questions :) Apr 30, 2016 at 6:10
  • ah, I just realized the usefulness of mentioning the desired result, good point. Apr 30, 2016 at 6:15
  • Most folks use o-rings to quieten a keyboard. This quite literally is the first time I've heard of someone using it to handle key travel - and stacking orings may make sense here, if you wanted different key travel with different keys, and you wanted to tweak it. Which may not be the case here.
    – Journeyman Geek Mod
    Apr 30, 2016 at 6:22
  • Do you know why so few people seem to be interested in reducing the key travel? My goal is to get a flat keyboard with the shortest travel distance and lowest actuation force possible. Apr 30, 2016 at 15:11
  • People buy the appropriate keyboard for it. I'd actually consider a chicklet keyboard or even a touch sensitive capasitive keyboard then.
    – Journeyman Geek Mod
    Apr 30, 2016 at 15:14
  • I'd also add the travel distance and actuaton force is part of the 'experience' of a mechanical keyboard
    – Journeyman Geek Mod
    Apr 30, 2016 at 15:17
  • Thanks, I was thinking about capacitive touchscreens too (I'm surprised nobody mentioned it on hardware recommendation), but I couldn't find any non-compact touchscreens used as a computer keyboard with decently good reviews (I could only find the Cool Leaf Keyboard, which seems to have quite some issues), I don't know what the actuation force would be, and I am a bit wary regarding the lack of short absorption. As for chiclets keyboards, I couldn't find any with a low actuation force and bottom out force. (I have one 60cN) Apr 30, 2016 at 15:50
  • So I was thinking of taking one Corsair rapidfire K70, and adding o-rings so that the travel distance is just a few mm more than the operation point (hoping it won't create issue to actuate keys), which should be around 50cN and linear, with a ca. 1.8mm travel distance. Apr 30, 2016 at 15:56
  • Now that you mention it, it would be good if the proposed question specified the sense in which the two strategies might differ, e.g. noise.
    – Ben N
    Apr 30, 2016 at 16:39
  • @BenN done: superuser.com/posts/1071438/revisions . That being said, I don't think it would be overly broad not to specify it, but in my case I just care about one aspect, namely key travel reduction, so I don't mind narrowing it down. Apr 30, 2016 at 17:51
  • @FranckDernoncourt: The revisions and clarifications on the question sort of highlight what is unclear (at least for me). Your overall objective is to minimize key travel, which I would consider on topic. However, the actual question is the difference between doing that with a single o-ring or a combination of smaller ones. So the question, itself, isn't about key travel, it's about the difference in characteristics between two o-rings and one. Why are you considering accomplishing the overall objective with two instead of one (that's the crux of the question)? (cont'd)
    – fixer1234
    Apr 30, 2016 at 18:10
  • There are probably lots of people who can address inserting an o-ring, but probably nobody who can address the effect of using a specific combination of smaller ones.
    – fixer1234
    Apr 30, 2016 at 18:10
  • @fixer1234 It's difficult to find thick o-rings. May 1, 2016 at 22:39

My take on the question is a little more limited than Ben N's, and we differ on your specific question. Take some examples of question focus:

  • Making existing hardware work the way it was intended: clearly on topic
  • Building a system or modifying a system by combining off-the-shelf components (and not a shopping question): I can't readily think of anything that would be off-topic
  • Repairing a system or device using commercially available replacement components that are intended to be user-replaceable: probably on-topic
  • Designing or building (prototyping), your own device from scratch: generally off-topic
  • Re-engineering a device by modifying its circuitry or mechanical design: generally off-topic
  • Tweaking a device to improve its performance or characteristics in ways that don't involve substantive changes to the original design (things that wouldn't void a warranty): probably on topic

The kind of change you described in your question would be an example of the last bullet. The issue I had was more with the focus of the question.

If it asked something like, "Is there a way to limit key travel without re-engineering the keyboard", a solution might be sticking 4mm thick o-rings under the keycaps. However, the question asked about the difference between using 1.5mm+2.5mm o-rings vs. 4mm o-rings and the clarification on what kind of difference you anticipated talked about the physics of the o-rings and the user's experience.

I thought this focused the issue on mechanical design and material science, which to me, is outside the site's scope. The effect on the user is something that could be determined only by experimentation. So unless somebody already tried exactly the same combination of o-ring sizes and material (a long shot, especially since you didn't mention the planned material), it would attract guesses.

This question was a tough call for me, a grey area. If the community responses here indicate that the majority of users consider it on-topic, I'll retract my close vote.

There was also a question of whether you were simply asking whether a 1.5mm thick o-ring plus a 2.5mm thick o-ring were the same total thickness as a 4mm thick o-ring. If that was the intent of the question, that isn't really a computer hardware question.

  • Thanks, regarding the last paragraph I precised the question. Apr 30, 2016 at 5:02
  • o-rings arn't just about key travel, its also about noise reduction. Materials may matter here. As the resident keyboard geek mod... I'm kinda debating what the correct answer for this myself ;)
    – Journeyman Geek Mod
    Apr 30, 2016 at 5:19
  • You're definitely right about the material science aspect; physics and engineering questions aren't ideal even when they touch on computer hardware.
    – Ben N
    Apr 30, 2016 at 15:45

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