Criteria
My three box vertical top bar hive.
I've come up with my own version of a vertical top bar hive using the following criteria:
- Designed for prolific bees in a northern climate.
- Tall enough for small cell sized comb development.
- One box per season rotation.
- Square configuration.
- Interchangeable cover and bottom.
- Self spacing top bars.
- Comb spaced at 1 1/4".
- Migratory.
- Stackable.
- Conventional construction material.
- Easy construction with minimal cuts/parts.
- Optimal material use.
Warre'? Not Quite.
This design is loosely based on the principals of the Warre' hive. It's larger and taller. The walls are thinner. And a simple migratory style cover/bottom board replaces the Warre's elaborate insulated cover. Here's why this is a better design for my beekeeping.
I've noticed, in my horizontal top bar hives, that the bees will initially draw out a comb about 12 to 14 inches wide, then come back later and finish the rest of the comb's width with drone comb. An optimum comb width might be in this size range. So, I've set the hive width there.
Brood comb cell size decreases at about a 1% rate down it's height. To get an effect small cell sized core requires comb at least 9 inches tall. A small cell core was very evident in my 15 inch tall top bar hive comb. And it's a necessity for optimum hive health. So, I've set the height in this range.
In my climate, a prolific colony can function and over winter best in a three deep Lang hive. That's about 7800 cubic inches. A taller, square, hive would need at least four boxes to be manageable. That's a much larger hive than is normally required for Europe's very conservative native bees on which the original Warre' design was based.
My cover violates several of the basic principles for the insulated, ventilated covers of the Warre' hive. But my winter condensation observations indicate this cover should be sufficient for my climate. If additional insulation is needed, blue constuction foam can be applied externally. And a canvas cloth can be placed underneath the flat cover for additional sealing between the top bars.
The flat cover/bottom boards are convertible and stackable which is almost a necessity for a migratory hive.
Plans
Here's what I've come up with. It's a very simple hive that optimizes material useage. And minimizes labor.
I've used Google Sketchup to draft up the plans. It's a free 3D CAD program. It has a very intuitive interface and is quickly mastered. With it you can enlarge, rotate, manipulate, measure, section, and edit my Vertical Top bar hive Sketchup file in any fashion you choose.
If you like the design, but want different dimensions. Just rescale it. You can stretch or squeeze it anyway you like.
Different hive components are on different layers which can be viewed, printed or not.
Construction
Four box vertical top bar hive.
Two pieces of lumber 1" x 8" x 3/4" are glued together to comprise the building stock. The sides, cover and bottom are cut from it. That allows a square hive, 14 1/2 inches on a side.
Boxes
The front and back have a rabbit cut in them for the top bars. And one along each side to protect the open grain of the sides, which reduces the sides length to 13 3/4 inches. A lifting cleat is fastened to the front and back of every box.
Top Bars
The top bars are cut from 3/4" stock. They are 7/8" wide and 13 3/4" long. Two finish nails, driven to the proper depth, provide a 3/8" space between the bars and allow self spacing. A thin notch is cut down the center of the bottom side of each top bar for a foundation based starter strip or a bead of beeswax.
Cover/Bottom
The cover and bottom are identical migratory type components. They have 3/8" wood strips around their edges to provide a proper bee space. Except the bottom lacks a 3/8" wood strip across the front, which provides the entrance. This front strip is tacked in place and can easily be removed or affixed converting a cover to a bottom or vice versa.
End grain is exposed on these hive parts. But I found that the conventional ways to cover them actually traps moisture causing them to rot. So, I've left them exposed.
With the minimal management needed for this hive, both the cover and the bottom are nailed to the hive body with galvanized roofing nails.
Management
Management is very simple. At the end of the season, the hive is hefted to determine if it's heavy enough. If so, the top box is removed and its' honey is harvested. Then, this empty box is returned to the bottom of the hive. If not, the hive can be fed. Or a spare feed box, previously set aside, can be placed on top.
I haven't built or managed bees in this hive. But it's the most interesting project on my list. I let you know how it goes.
Enjoy!
...to be continued
