Here’s a practical cut I made to create a custom switchplate for a 4" standard metal electrical box. I needed the decora-style opening for the speed controller, and the round hole for the industrial panel switch. I made this in two parts - one being the cover with the engraved lettering, and the second being a standoff so that the panel switch had more clearance as far as depth into the box goes.
Another practical note that I believe has been mentioned here before, the website mcmaster.com, in addition to having all sorts of interesting parts, tools, and materials for sale, also has CAD files for most of the things they sell. So if you want the layout and spacing for an electrical box and various cover options that are available, you can look up the parts, download the CAD files, and import into your vector editing software… saves the hassle of taking lots of measurements.
Nice practical print one thing you might want to look into is local electrical code requirements, sometimes it is required that the plate be fire proof/ resistant.
The wooden switch plates I’ve seen sold in stores have come with a metal plate. My guess, is that the reasoning is if one of the wires inside the box contacts the switch plate the material should have a certain resistance to catching fire.
Not a big issue and even less of one if you do the wiring yourself and trim the ends of your wires short/don’t stuff an extra foot of wire inside the box, etc…
one thing you might want to look into is local electrical code requirements, sometimes it is required that the plate be fire proof/ resistant.