Folks, I'm going to move a Lang to the top of a Top Bar Hive, and try to transition the hive to the TBH this way. If the girls don't start building down I will either move them back to a standard bottom board and leave this as a Lang hive or do a cut out. I was hoping they would take to this method and I would probably over winter with the original brood box as a super and in the spring remove it. Depends on how well the hive is working. I've heard mixed results from the type of transition, so I'm looking for input.
This is the idea I had for an adapter. Basically it is just a sheet of plywood cut to the same size as the Lang body. Then I would route out or dado cut 11 slats that are 14 inches in length, and 3/8 inches wide. Just beyond the end of each slot towards the handles there are 3/8 inch holes drilled, a half inch in depth. I'll insert a 1 inch length of dowel with the protruding end slightly tapered. These are used for aligning the slots with the top bars.
For the top bars I need to make 10 new bars that are 1 inch thick. Then I will need 3/8 inch thick spacers. These would be cut originally to the full length of the bars (19 inches), but then I will cut out a keystone piece approximately 14 inches or so in length. The reason for this is that when I finally remove the Langstroth hive body I can easily place the cutout pieces into the gap and nail or screw them into the side of the top bar, ceiling off the top of the hive.
Another and simpler option would be to just remove all the material between the first slot and last slot and ditch the alignment pins, so basically this adapter plate would function as a gasket. No doubt that is simpler to make, and the alignment pins are probably overkill. The main reason for me not wanting to cut out the whole center is I don't want all the comb/propolis building up in the 1 1/4 inch between the bottom of the lang frames and the top of the top bars. If it seems like a pain in the behind I can always just open the whole thing up.
Has anyone tried this? I saw that Phil Chandler had done something similar, but in his case he just used a Lang brood box for the top bar hives and made sloped sides. I could do this as my top bars will fit into a lang, but I liked the idea of moving directly to the top bar. Plus I would have to build out the sides in the Lang box for the Chandler method. Any comments or suggestions?