All I can say is 1/2 inch plywood is a dream compared to 1 inch plywood! The bike box is light and lovely. So if you are inclined to make one for your self this is what I used;
Base for box 18″ x 16″, 2 sides 16″ x 9″, 1 side 18″ x 9″ and 1 side 18″ x 5″
8 Medium/Large L-shaped brackets to attach the sides to the base and 4 Small/Medium L-shaped brackets to attach the sides to each other. Size depends on how big you want to go (doesn’t it always). You will likely need 48 1/2″ wood screws as well.
I then added two circle hooks on the side with the 18″ x 5″ board so if you are moving a lot of goods you can run bungee cords or string etc thru them to build this side of the box up. The reason this is cut down …. makes locking your bike up next to another bike much easier when their seat or handle bars have somewhere to go other than bumping up against a wall of wood. And if you are out shopping and buy too much then don’t worry just tie one of your bags to the handle (which you have installed on the back end of the box) and flip it over the side. Gives you room for 1 more bag!
Two other good things to do if you are so inclined; drill some drainage holes so the rain flows thru instead of collecting and a clean is easier to do when you don’t have to tip the bike over. And secondly I added reflector tape cause then you never have to worry about your lights being left and home, burnt out or stolen.
To attach the bike box you will need a bike rack, another piece of wood and two screws with 2 wing nut bolts. Wing nut bolts are much better than simple bolts as you will need to be able to tighten them on occasion and once in a while I like to take the box off to throw it in the back of a car to get home.
UPDATE – SEPT 2nd – The wood will not stay together with simply screws. What I did not take into account was that other old school boxes had a sort of tongue and grove thing going on which was key in absorbing the shock from the road. You will need to glue the wood together as well and hinge. Best glue ever – Gorilla Glue (Thanks to my bike shop guy!). Super strong but don’t use too much or it overflows and it is not a pretty sight.