How to fix D Rings to 3mm Board Kitchens, doors, rails, stud, tables, chairs, stair cases, garden furniture etc... Find answers and ask questions here!

[MollyFinch]

I'm making a mirror by sticking mirror tiles to 3mm board and then planning on hanging it on the wall with D rings. My problem is that I can't find screws as short as 3mm for fixing the D rings to the backing board. Any ideas?