I have an adjustable double roundover bit which I use on a router table to make frame mouldings. The guide says the max. cutting width is 31,75mm and minimum cutting width is 11,1mm. The smaller widths are achieved without use of the bearing. I would like to use it at 8mm width and the many varied shim washers would allow this. However I'm reluctant to go against the instructions as I'm not an experienced router user and know they are potentially dangerous tools. I can't see any obvious reason why this double roundover bit should not be used at narrower cutting widths than 11.1mm - any advice from experienced users would be much appreciated.