Hey everyone, Nigel from Flashquark.com here.
I’m currently in the process of designing a new switch and deciding on whether the spring should be a one-stage or two stage spring.
For those of you who aren’t acquainted with the difference: One-stage springs are the original spring type that used to come in all switches and have a straightforward design that you would imagine a spring to have. Two-stage springs are kind of like two springs connected together such that the ends meet together at the middle of the overall spring, and for this reason, are longer than one-stage springs.
You can see the difference between a normal spring and two-stage spring in the photo below.
For those of you who have tried both kinds of springs, I wanted to see which spring type you prefer and for what reasons.
I’l start with my personal preference which is that I think two-stage springs only offer benefits and no disadvantages. The design of the two-stage spring makes it longer than a normal “one-stage” spring. This means that the spring is compressed more than a one-stage spring during the unactivated state, and it reaches its bottom out weight more quickly. This makes the downpress feel more firm and consistent, as there is a smaller range of forces between the beginning of the keypress until bottom out or even actuation. In addition, the upstroke after lifting your finger is noticeably faster, meaning that there is the ability to rapidly repeat keystrokes in a shorter amount of time. From my experience, two-stage springs are also less likely to have spring ping because being more compressed even in the unactivated state means that there is less room for the spring to move/rotate around.
already has a two-stage spring, so I just wanted to see if there was any reason for making our next switch a normal one-stage spring kind.
In any case, that’s just my personal observations and preference, but I’d love to see what your guys’ preferences and reasons are for spring type so that I can better make a decision for our next switch release, thanks!
Update:
In case you guys are interested, I cut out the side of a Quark switch so that the spring action is visible. In the videos below, you can see what a normal one-stage spring is like versus a two-stage long spring when the switch is being pressed. Ignore the clicking noises in the video. This switch is normally very silent and smooth, but during the process of cutting away the side of the switch housing and stem, I accidentally cut away part of the stem slider and so it gets caught on the switch leaf and makes a clicking noise when the stem is pressed down.
Granted I don’t have a ton of experience with the different spring types yet, however what I have really been liking about the two-stage springs is that you can get lighter weights while still having that snappy return like you were saying.
Stages don’t really matter all that much, ime. it’s the length of the spring that makes the biggest difference. It can make the return a lot snappier and add some pre-tension to the initial key press. I don’t even know why “stages” have become a thing. I feel like it can only lead to problems down the line. because the “stages” add more material to the spring, meaning the stem could potentially bottom out on the spring instead, which wouldn’t be optimal. And i’m not sure if they even make a difference in feel. I have some 2, 3 and 4 Stage springs and they feel the same to me, as all the stages throughout the spring are the same weight anyway. but i could be wrong, i don’t know the specific of why there are sections in springs there.
With linear switches, I agree. With tactile switches, there are differences you can notice. But it’s difficult to even describe the behavior because overall switch behavior is a lot more complex. The only thing I can share with enough confidence is that multi-stage springs are extra bouncy.
My current favorite springs are (from weakest to strongest):
53g 3-stage (MM Studio)
58g 2-stage (CK)
60g L (TX)
As to why three, I found that switch swap often calls for spring swap. Same switch that felt fine in one board will feel either tad too heavy or light in another board.
Are they all the same length, though? Longer springs add more pre-tension to the key press, as the spring is already a little bit compressed, pressing the stem up against the housing more than short springs. And they also introduce more tactility, as you may have noticed. That’s mostly the length, but not the stages. So far i haven’t found any difference in feel between same length springs with different stages. I feel like doing something like making the springs have a conical shape has a bigger difference to the feel. Maybe even “hourglass” shaped springs.
I also tested several 22mm single-stage springs but they didn’t make my favorite spring list. I use multi-stage on tactiles bc they matter more there. With linears, I just select spring based on weight bc, as you discovered, they’re pretty much same as single-stage springs.
FYI, my favorite spring list don’t really mean they’re the best. Instead, they are used most often among springs I have and, hence, I have a stockpile of each.
I’m not sure about the higher number of stage springs since I’ve never used them, but two-stage springs don’t compress so much that the stems would be able to bottom out on them. As for adding stages, I think they are mostly for structural support so that the middle of the spring is less floppy when it is being compressed.
I personally like shorter springs for both linears and tactiles as i think the faster return with longer springs is a bit too jarring for me especially in tactiles. With linears I can handle it fine but with tactiles it just gets fatiguing after a short bit and i want to switch to another switch. I consider shorter spring sarround the 14mm range and long springs too be in the 20mm range.
I have to admit that I’ve mainly just played with two-stage springs in linear switches, but I will definitely have to test them out in tactile switches to see how they affect tactility and overall feeling.
When you mention the noticeable differences, do you feel any differences based on how many stages a spring has (two vs three) or do they feel similar as long as they are multi spring?
For springs past 16mm I prefer “stages” because I find they are easier to work with since they are much less prone to getting bent and tangled in shipping.
For linears I tend to prefer dual or tri-stage springs, like the TL53 or the classic 63.5g found in many Tecsee switches. For tactiles I tend to prefer single stage springs so that I can focus more on the feel of the bump than the feel of the springs. In general I enjoy long springs for the snappier returns.
In case you guys are interested in looking at what a spring looks inside the switch during activation, I posted two videos in the original post showing a switch with one side cut out so that the spring is visible sp you can see the difference between how a one-stage and two-stage spring operate.
I’m not sure what the cause is for the single-stage, but I think the reason the two-stage compresses more in the lower half is because of the way that the spring is bent when it is partially compressed inside the switch when the switch is not activated. It is bent in such a way that there is less resistance from the bottom half of the spring and therefore the compression occurs more in the path with less resistance. When the spring is compressed outside of the switch, both halves compress equally towards the center of the spring.
I’m all about the 2-stage, they work great in my Gateron Ink Box Pink and Ink Yellows.
And the main reason I like them is that they don’t feel slow on the return when using sub 60g springs
From a purely mechanical engineering perspective, you would assume only Hooke’s law would come at play. Hence, only the spring length and its stiffness constant k would be important, where the latter is determined by the spring material and its wire thickness. For that reason, I cannot recall any other typical mechanical application where “multi-stage” springs are being used.
However, this is not counting with the buckling effect, so nicely described by @flashquark above. The upper part of a two-stage spring may experience some support from the stem and buckle differently than the lower part that is perhaps more free to buckle. This gives rise to interesting effects not seen in run-of-the-mill mechanical engineering applications. In this context, two-stage springs make sense, but three-stage probably not.
Personally, I have no experience with two-stage springs —I probably should now,— but I do like the 68g GAZZEW stainless steel springs as used in the Boba U4Tx switches.
As a matter of fact, I recently replaced the shorter and narrower springs of Kaihl Silent Brown switches with those longer and wider 68g GAZZEW springs. This not only increased the actuation force, but also increased the tactility and stability of the switch.
Mind you that the stem of the “boxed” Kaihl Silent switches is in fact a hollow tube, only slightly wider in diameter than the GAZZEW spring. This offers the spring a lot of support, which will result in much less buckling at the top, compared to the bottom part of the spring. As said before, the effect of this particular spring swap feels as an improvement for this switch.
