Making a letter opener case from balsa wood. My opener ended up being about 6 mm thick. I had some scraps of balsa wood with exact the same thickness, means perfect for this build. I’ve used PVA glue to hold the wood pieces together. The neodymium magnets (8 mm diameter, 4 mm thick) are glued in with epoxy. Yes, drilling these holes might be tricky, but not impossible.