This is a parametric switch tester built on OnShape. It containt a top and bottom part but the bottom part is optional as the top part already contains enough space to add rubber feets if wanted. 
If you feel the need to add the bottom part you will need to add M2*5*3.5 Heat Set Inserts (or shorter with the same width) and it uses M2 screws.

I've already added the files for a few different sizes but if you want other sizes you can change the size if needed [x,y] => [rows, columns] (you might need an account to modify it)

Link: https://cad.onshape.com/documents/eeff3bf516d9d0695a9edc56/w/e56ea32f992e34110e58fc55/e/64148d489e0508f9261e32e3?renderMode=0&rightPanel=variableTablePanel&uiState=66f0495df0b9c47dcc42ae3a

If you can't modify the cad files feel free to tell me about it! 

Update:
- Changed the heat insert hole radius due to feedback