Have you tried the new "birds mouth" router bits? You can buy them for any number of sided boxes,(as number of sides determines the new angle).
www.pricecutter.com/html/catalog/productGroup.asp/334481
I am also into box making and I have a bisquit cutter that cuts very small bisquits. Some,no longer than a 1/4". Maybe this could also be an alternative.
www.pricecutter.com/html/catalog/productGroup.asp/334481
I am also into box making and I have a bisquit cutter that cuts very small bisquits. Some,no longer than a 1/4". Maybe this could also be an alternative.