It is technically possible to find or manufacture metal backs that will work with this machine, it is highly unlikely. Even if you found "2 inch" backs that fit into the machine, there is no telling they would work with the shells we carry. Even other manufacturers button supplies that do work in our machines together don't work when you use a shell from us and a pinned back from them.
You probably should just get a 2.25 inch button maker instead.
Usually when people ask for a 2 inch button, they're actually picturing a 2.25 inch button, which is a much more common size.