Hi since I have two lovely as new squirrel fans from which I intend to make a large rectangular ceiling type boxed fine dust extractor.So can anyone show me any books designs on this type also interested in a floor mounted for later in the yeaar, but this type on the ceiling would be best for these fans.Any blogs articles books etc with designs on this type I would like to see and design my own.You've seen them a box rectangular or sometimes a drum design for the smaller ones fitted on chains from the ceiling and remove the very fine airborne dust.I have made one already with a few bathroom fans and it works but maybe I need to see a more professional design on this .Or indeed as said for a leter in the year project the floorstanding type as I have an impeller type metal fan for this with a 110 volt motor thanks any help would result in a big fat (cheque) no sorry delete that what I mean is thanks