The micro switch is affixed to the base using M2 or #2-56 screws, the holes are sized so that the bolts should self tap.  Any length a few mm more than the width of the switch should work, I had really long ~15mm long ones on hand and made the holes deep enough to fit.
The cover and strain relief are held on with M3 bolts, again self tapping (#4-40 bolts will work here too) I used 8mm long bolts, 6mm would work also.  The cover slides on over grooves, and the bolts fix it in place. 

Switch compatibility: 
The design is for switches with mounting holes 9.5mm apart.  The overall body of the switch should be less than 19.9mm overall.  this is a common form factor, some examples of this size switch: [https://www.amazon.ca/DAOKI-Switch-Roller-Momentary-Terminals/dp/B07YKGL61S/](https://www.amazon.ca/DAOKI-Switch-Roller-Momentary-Terminals/dp/B07YKGL61S/)

Or this Omron example from Digikey: [https://www.digikey.ca/en/products/detail/omron-electronics-inc-emc-div/SS-01GL2-3T/5236930](https://www.digikey.ca/en/products/detail/omron-electronics-inc-emc-div/SS-01GL2-3T/5236930)

Or this inexpensive option from Aliexpress: 

[https://www.aliexpress.com/item/1005002373206032.html](https://www.aliexpress.com/item/1005002373206032.html)

The adjustment slots in the base are 4.2mm wide, so M4 or #6-32 will fit perfectly, but you could just use M3 or #4-40 with washers too.   

STEP files are included.