Long overdue project was to spin one of these Forstner bits around and around in the right location...
To put locks on a cabinet.
It isn't as secure as a safe and wouldn't stop a determined thief. But it will keep nosy relatives from snooping.
Right now I just have my self defense ammo stored in there, but I will stuff some computer backups in there and other important things that are not quite important enough to be in the safe.