This box appears to have been reinforced with a face frame by a previous owner. The contributor of this example has this to say about it:
“The original outer dimensions (not including the added framework) are 36 1/2″ long x 11″ wide x 9″ high. The inner components, I imagine, would be somewhat variable depending on the specific miter box dimensions. I also believe that the crossmember that the left side of the miter box rests against has been cut down and originally went all up to the lid. This probably helped support the lid and kept any errant pieces from entering into the miter box compartment during shipment and damaging the paint. Also, the pieced together spacer block is interesting. I don’t know if it is original or added by the owner, but it wedges fairly tightly between the back of the crate and the blade of the saw. It is shaped so that it is prevented from moving by fitting between the plate that the diagonal saw guide holders are attached to and the center crossmember. It allows for a little side to side movement of the saw, but without it in place the back of the saw makes contact with the front saw guide support on the carriage.”
Photos and measurements courtesy of Ben Bama, Seattle, WA.
A Langdon Mitre Box Reference 