Two small things conspired recently into making me think. I bought a cheap super for my Langstroth hive on ebay. When it arrived I had been sent a national super. The supplier claimed I had ordered a national and the ebay emails are unclear. I could send it back and get a refund of the cost but not the postage. It was not worth my time and the expense so it was assigned to that pile of unused bee equipment that all beekeepers have.

The second event, which triggered this project, happened at an open apiary where our host, Simon Croson, showed that if you have different size boxes on your hive often a simple length of wood can use to seal the gap. It occurred to me at the time that is was a good short term solution but not very robust for the long term. Also it would only work if the box on top did not protrude over the lower box. What was required was a board similar to a crown board that sits on the bottom box covering any parts that may be exposed by the differently sized top box. A hole in this joining board would give bees access to the top box and also provide a floor box where it over hangs the bottom box.

Then on a rather wet and deary afternoon it occurred to me that there must be a ‘general solution’ to this little problem whatever the sizes of the boxes. It took me rather longer to work this out than it should have done but all you need to do is measure the outside and inside length and width of both boxes. The dimensions for the joining board are then the longest outside length by the longest outside width and the hole in the middle is the shortest inside length by the shortest inside width.

To test this measured up a Langstroth box and the national super I am never going to use. I then cut out the joining board from a piece of corrugated cardboard from my last bee equipment delivery. It worked!

Buff coloured cardboard can be seen between boxes


I proudly showed off my invention to Mrs Beekeeper who dutifully appreciated its cleverness. Then after a pause she asked if the cardboard would get rather soggy in the rain. Pointing out that it was a prototype and that I did not want to make a real one and waste a large piece of plywood by cutting a large hole in the middle of it for something I will probably never use. A question from Mrs Beekeeper about why I had bother to make it was dismissed as irrelevant. I had worked out a general solution. It would apply to any two boxes stacked on top of each other. Then with one of those surprising and delightful throwaway suggestions Mrs Beekeeper ask why I did not just make it from four strips of plywood. I was about to point out that you can not just join bits of plywood by their short edge when it occurred to me that it would be a nice extension to the general solution to calculate the size of the strips of wood. Fortunately it was raining and I had the whole afternoon in front of me.

By midnight I had worked it out. The size of the strips was relative straightforward to work out but how to join them together? The Internet suggested many and all various ways all either too intricate to be worth the bother or simple, like screwing on metal plates would ruin the general solution and turn each one in to specific solution for each combination of boxes. Then it occurred to me. Two joining boards with overlapping strips and glue them together, no joins, no connection plates, no screws or nails.

At this point I have to make a rather embarrassing confession for my age and sex; I have never been able to saw straight. At school they made me do technical drawing instead of woodwork. So the prospect of cutting long strips of plywood was just not realistic. I very nearly went down to Turnbull’s and got them to cut up the strips (they will do this but may charge you ‘machine time’ which is not cheap). This would have meant buying a large sheet of plywood which just seamed wasteful. So I got out my little used circular saw, attached the guide tool, clamped some 3mm ply to my workbench, took a deep breath and cut the first strip. I then adjusted the guide tool to the correct width and cut the first strip again. Half hour later I the eight strips ready to glue together. I even managed to saw the strips to length with a hand saw although I had to throw away the mitre block as I had sawn into it once too many times.

The glueing is easy. Arrange the first four strips on a flat surface. Apply some waterproof glue and place the overlapping strips on top. Check that the corners are a right angle. Apply some pressure to the strips. I use clamps but weights on the top surface is just as good. Lastly if you want the board to last, waterproof it.

Finished joining board demonstrating my lack of sawing skills

General solutions are usually easy to implement on computers so I decided to write this up and add the following rather inelegant form below. All you need to do is fill in the top eight boxes and the sizes of the strips will appear below. If any of you use this please leave a comment below.

Now, does anyone want an unused Langstroth to national joining board?


A General Solution