Waldemar,
        Cell size measurements are taken 10 cells at a time. The thickness of the wall is taken into account and 10 cells in any of the three planes should measure 4.9cm top tolerance for full small cell regression. Although you measuring, wall to wall over 10 cells, when you do the math and remove the extra wall, the difference between same side to same side and outer to outer ends up being only +.1 or .2 mm when spread across 10 cells. So if you are measuring wall to wall over 10 cells and you get 4.9cm, then removing the thickness of the 10th extra wall, you get 4.88mm to 4.89mm for each cell same side wall to wall.

The goal in small cell regression is to achieve 4.85mm cells, 4.9mm is the top tolerance or the no bigger than number. Some small cell beekeepers have brood cores of 4.6mm in a majority of their hives. I have hives ranging 4.6mm - 5.2mm with the majority of hives between 4.7-4.9mm cell sizes.

For the record, I use no foundation at all.

Scot Mc Pherson
McPherson Family Honey Farms
Davenport, IA
Bradenton, FL

-- Visit www.honeybeeworld.com/bee-l for rules, FAQ and  other info ---