This is a basic engineering task of understanding the tolerance on an interface between two parts.
To create a Cherry compatible switch, one would go and measure ~100-200 Cherry stems (preferably with a micrometer which is higher resolution and more repeatable than just calipers), calculate the min, max, median, and standard deviation, write a specification and work with the clone switch vendor to make sure that their switches fall within that specification.
I’m seeing so many people making different excuses for why this isn’t their fault, or they had no idea the stems could be a problem, or whatever… and the one ‘fix’ I have seen proposed is to change the spec to 1.30 +/- .020 mm, which is still not matching up with the range that Cherry switches fall in
All that you have to do is read any tutorial on sourcing electronics from China and the name of the game is verify, verify, verify, verify. Don’t assume things will be okay or take anyone’s word for anything, or you’ll get your genuine parts substituted with “compatible” parts that don’t actually work, etc.
These dimensions are something that should have been checked and verified by the people who have been selling thousands and thousands of dollars of switches to the community, that the switches they were importing were truly compatible switches. Not “oh woe is me there is no way I could have seen that”.
Don’t even get me started on the fact that Input Club is going to still sell bad switches with the Kira, and refuses to delay the project to make this situation right for all of the switch options.
Best thing to do here - open trash can, toss box switches in trash can, refuse to do business with any vendor that won’t hold their stems to as-measured tolerances of Cherry stems.