According to Frank & Phronsie Humphrey:
>
> These escapes are very easy to make.  Cut a piece of 1/8" hardware cloth
> into a triangle measuring 8" on each side.  Next cut about 1/2" off each
> corner.  measure the new length of the sides.  Cut 3 pieces of 1/4" plywood
> 1/2" wide and the new length of the sides.  Staple the hardware cloth to
> the plywood strips leaving just enough space for 1 bee to exit at the
> corners.  Attach to the top side of inner cover, using #4 or #6 screws.
> Invert inner cover and put it below supers to be removed.  Make sure to
> beeproof the top supers or else they will be robbed out.
>
> Screening can be used in place of the hardware cloth but it is not as
> rigid.  There is a variation of this on the market that has a triangle
> within a triangle however I have found that this works just as well.
>
> Frank & Phronsie Humphrey
> [log in to unmask]
 
I use 1/4 inch plywood to make an inner cover with 3/4 inch
edges and cut a clover-shaped hole in the plywood with 4 cuts of a 1 1/2
inch holesaw.  I use four 1/4" strips to make a diamond whose
corners do not meet by 1/4" and cover with 1/8" mesh
hardware cloth.  I find that the large opening in the board and
the 4 exits clears them out rather quickly, usually overnight.
 
Fred in Virginia