National Version
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Rational "Crown Board" or "Coverboard"
Not really required... But for completeness sake

A method of closing off the top of a Rational 'top bee space' bee hive so that the main protective roof can be easily removed with little disturbance to the bees.

The Grain should run along the longest dimension of any part.

Cutting of parts (all dimensions in mm).

  3rd Angle projection
QtyLengthWidth ThicknessMaterialUsage
1460460 9Exterior PlywoodMain Panel
2460 199PineLong sides of rim
2422 199PineOther rim parts

This item is identical in size and construction to the "National Crown Board"

Use with rim downwards for bottom bee space or with the rim uppermost if top bee space is required.

The holes shown are to suite the standard porter escape.

this page gives methods of cutting such holes. For normal use a single 33 mm central hole proves to be adequate.

Note 1.
9 mm plywood is specified owing to it's greater rigidity and freedom from warping. This durability outweighs the small cost saving of using thinner material.

Note 2.
9 mm is specified for the thickness of the rim material but commercial supplies are often of 8 mm thickness, using 8 mm is unlikely to cause any problems.

Assemble using a waterproof PVA type glue and 16 mm pins or staples.

  Rational Crown Board

If you wish to use this item as a cover board in a system that uses bottom bee space, then add the Rim Parts.

If you are using a top bee space system, there is no need for the complication of a rim. Many of those that I used personally were only squares of waterproof ply 460 mm on a side and 9 mm thick. These had a 33 mm diameter central hole and were treated with linseed oil and had the outer margins and outer edge painted with exterior grade enamel paint, which helped to stop absorbtion of water into the grain.

Rational Crown Board as used by Dave Cushman

Even the simple plain board is not required if the solid, insulated "Rational Roof" is used instead of a telescoping outer cover.

 Written... Summer 2000, Revised... (details lost), Upgraded... 21 February 2006,
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