> I found a box of Dadant wire excluders with wood frames, barely used. The
> gap appears to be at or barely over 20 gauge (.161" or .162").

Some time back I decided to measure an assortment of excluders we have
around here.

The results are at http://www.internode.net/honeybee/Misc/excluders.htm

allen
http://www.internode.net/honeybee/diary/