Kailh Box Switch Stem Measurements and Possible Problems


ignore post, see next one

So here’s something interesting. I’ve taken a picture of a box jade and a box navy. See a difference in the stems?

On the x-axis of the jade, we have the small bulges which many of us theorize as the culprit behind the keycap cracking issue. On the navys, we don’t have those.

I’ve measured the box jade x-axis thickness on the bulge at 1.33mm and the y axis thickness to be 1.15mm.

On the box navy I’ve measured the x-axis thickness is 1.31mm and the y-axis to be 1.12mm.

This is only a sample size of one each, but I think this is interesting to look into.

For those who can take a look at their other box switches, do you have ones that look like they have a bulge or ones without a bulge?


@Manofinterests I noticed this last night but with both switches being Box Royals. Not only are they visibly different thickness but the actual purple color is different. Sadly I had mixed up the bag from my separate Box Royal orders so I can only assume they are from different batches but it was still interesting to see this noticeable difference from the same switch.


Which comes from the newer batch, the left or the right?


Well well well. Looks like you might be on to something. I never noticed before, but sure enough:


I believe the right one is newer but like I said I had sadly mixed up the bag.


Thanks for the clarification. I checked my remaining unused BOX Navies and they look like the one on the right and they’re all the same. They belong to the same batch and I bought them just last month from Aliexpress YMDK. Wondering if this issue is about older batches.


Okay. Here’s what I’ve found:

Switches that have the extra ridges (all purchases this year):

Hako violet
Hako true
Hako clear
Hako Royal
Box jade
Box white
Box brown
Box red
Box pale blue

Switches that do not have extra ridges:
Box navy
Box black (purchased last year)

But the thing is, it was the box black that broke my hyperfuse set. So, go figure.

Did I mention that I have a lot of box switches? RIP


Box Pale Blues from the last MD drop I received has the ridges.

Also, I think I see ridges on the navies in your photo.


I’ve looked at all my box switches (pale,blues, hakos, royals, jades, navies, and blacks) they all have the bump on them. The only difference I found is that for darker colors the bars are harder to see, but they appear on every switch I have. (I have samples from 2017 and 2018) I don’t have a macro camera to capture this but I am pretty sure they are on every stem, the difference is just an optical effect. Maybe the thickness of the bar changes though?


Yeah, i do see them on the navy in that pic. It was hard for me to see on mine so I’ll have to look again. Same for black


Good eyes @EightDiagram, I didn’t see those when I originally looked, because I didn’t zoom in hehe. I’ve taken some pictures under my microscope to confirm: Sorry for the mess, I dropped these switches on my carpet :stuck_out_tongue:

Box Navy:
Top View

Slanted View for ridge visibility
Pic 1

Pic 2

Box Jade:
Top View:

Slanted view for ridge visibility
Pic 1

Pic 2

I only have a handful of each switch, but I still wanted to have these numbers recorded.

Box Navys x-axis length y-axis length x-axis thickness y-axis thickness
1 3.99 3.98 1.31 1.11
2 4 4 1.31 1.1
3 3.97 3.97 1.31 1.12
4 3.97 3.96 1.3 1.11
x-axis length mean y-axis length mean x-axis thickness mean y-axis thickness mean
3.9825 3.9775 1.3075 1.11
Box Jades x-axis length y-axis length x-axis thickness y-axis thickness
1 3.97 3.97 1.3 1.12
2 4.01 3.99 1.32 1.13
3 4 3.98 1.33 1.13
x-axis length mean y-axis length mean x-axis thickness mean y-axis thickness mean
3.993333333 3.98 1.316666667 1.126666667

These seem to be pretty close to @Nebulant who measured 1.329mm for x-axis thickness mean and 1.098 for y-axis thickness mean. My x-axis thickness deviates .02mm similarly to my y-axis thickness.
My figures for navys deviates around .02mm from @Owlbert who got 1.3228mm for x-axis thickness and 1.13mm for y-axis thickness.

Since the deviations are pretty small, I think I can chalk it up to not having a large enough sample size.

I also unscientifically pulled out my really old first gen box whites which also appear to have the ridges. I measured a handful unscientifically and it seems like they all measure around the same as all of the data that has been posted on this thread.

So far, all the data that everyone has been posting seems to fall in line pretty closely with Kailh’s official specs on this matter. Based on these specs, it should also be noted that Kailh Box Brows, Jades, Blacks, and Reds are most likely the switches that will cause keycaps to crack with the highest frequency.

I hope GMK releases their own data or spec sheets soon so we can have another point of reference. I think knowing GMK’s specs to see if there are any official deviations or changes since October 21st 1987 and we don’t know if there have been changes since then.


Every box switch I have has the ridges, and I think I have at least one of all of them.

Also, when I measured my Axis thickness, I did it close to the center, I might have missed the lumps now that I look at it… pls dont make me measure again…


I also noticed cracked stems on a few of the keyboards I have box switches on.

I wanted to see if the cracking seemed related to stem thickness, so I did the measurements for one of the boards. The switches were box navy and the caps Devlin K series.

Even though all of the stems are within Kailh’s specs, there does seem to be some correlation with the cracking and the stem width.


@squab that is some high quality charting. Love it.

ps- sorry bout your caps :frowning:


But they are measured the same dimension.
Like a person who wears dark color looks thin, wears light color looks fat.



Correct, my measurements are within spec of each other if you see my posts


My BOX Navies seem to have the ridges too, purchased March 6, 2018.


Hello Guys!
I have compiled a list of stem thicknesses of different switches that people has provided to me.
You can take a look at it here if anyone is interested: https://docs.google.com/spreadsheets/d/1Wc59WnMRJs0gVBrOyh2bRQcPl28yL7lim-p-N0l1daQ/edit?usp=sharing

If you have some measurements of stems then send them my way and i will update the list with what you give to me.

I also trimmed the BOX part of a BOX Jade keyswitch to see if the stem size widened at the end, I can say that on my sample size of one that it does not widen or narrow at the end.


That table is rather interesting. The cherry brown measurement is almost as large as some of the box switches, it is probably an outlier since it is only a sample size of one.