Need advice on squaring up beehives
I am a beekeeper that needs some advice from woodworkers. I have some hive bodies that are in need of repair. If you are not familiar with hive bodies, they are the four sided boxes that make up a typical beehive. They hold the frames of honey comb. They are roughly 16 1/4 wide and 19 7/8 long and come in various depths. Several are stacked up to make up a hive. They are usually made of pine and are painted on the exterior. The kind that I use are constructed with simple 3/4 box joints.
The issue I am having is that the edges of boxes, (where the stack on each other) are wearing away in the corners. This occurs because we use a metal tool in the corners to separate the boxes. In addition, maintenance such as making corner repairs, sanding and repainting, etc. tends to wear these edges in the corners more than in the middle of each side. This occurs both at the top and the bottom edges. The net result is the edges develop a very slight curve to them such that when you place the box on a flat surface the corners don't touch the surface. When this occurs on the top edge of one box and the bottom edge of the next box, it can result in a quite noticeable gap. This can let in water. The bees have a way of sealing this up from the inside but they don't seal the outside. Which means water can sit in the gap and eventually rot out the corners.
I have a very good external grade epoxy putty I use to make repairs on these hives. I can apply a thin coat to the corners to build them back up. What I need advice on is a way to machine or sand the edges so that the entire box edge, (all four sides) is flat and square to the sides, and also remains parallel to the other edge.