Parts for Rim 9mm deep 12mm wide
At first sight a rim that is only 12 mm wide will seem
narrow, but there a is good reason for it.
The top rails of B.S. National hives have a wall thickness
of 13 mm or (1/2"). As the boxes are square any item with a rim may
be positioned in either of two mutually perpendicular directions.
Therefore a 12 mm wide rim cannot overlap the ends of the topbars
and thus we avoid the propolising mayhem that occurs with the standard
bottom bee space design.
Two Pieces 460mm x 12mm x 9mm
Two Pieces 436mm x 12mm x 9mm
Material can be Pine, Cedar,
Exterior Grade Ply or whatever else you may have to hand.
Glueing and screwing using countersunk screws will give a
reliable, long working life.