You typically need round head wood screw to mount things without damaging the hole. If you only have wood screws with flat head, you can convert it to have a flat bottom (like round head) using this adapter.

Measure the screw head diameter, head height, and screw body (with thread) and adjust in customizer to generate STL file. My recommendation is to screw around (get it?) with parameters, print it a few times to get it just right for your application.