Bought our apartment in the Netherlands recently, and we're trying to replace the beat up, landlord grade, hollow core doors, with something a bit nicer. The issue I'm having is that I've no idea what is likely to be going on inside the doorframe to attach the hinges. They have these little metal washers that are working as a frame attachment, but would like to know if anyone knows what these fittings for a metal frame are called, or how they work?
I assume they're similar to a drywall anchor on the inside, but I don't want to break one if it turns out they're welded on. A link to what the hinges look like off the door