The wood used to build the boxes should be 3/4 inch thick.
Some wood is planed to 13/16 inch something to think about if using a finger joint jig.
The dimensions should be 19 7/8 inches long and 16 1/4 inches wide (external)
You should have some space to move the frames around.
The Deep Box should be 9 5/8 inches deep.
The frame rest should be 3/8 inch X 5/8 inch.
Thanks. My boxes match the dimensions you list. The stock is 3/4" thick.
You have to space the frames out evenly in the box. If the frames were tight in the box, you would not be able to get the frames out after the bees had glued everything in.
I figured I'd need some room, but I was surprised at how much room I have. I searched quite a bit before posting here, and I kept looking after posting. I finally found a post that stated that you should push the frames together and center them in the box.