theaded bearing tube mounting system
I machine my bearing holders and only have about 1/2 inch or so sticking out behind my stator. There is a notched flange located about an 1/8 inch behind the stator. Behind that is the threads. 3/8-24 for 7mm od. bearings and 5/16-24 for 6mm od. bearings. The threads don't have anything to do with the bearings, that's just what fits inside of what. I use an electrical type hex nut (found on toggle switches or lamps) and re-tap them as required. (3/8-32 would work better, but I don't have that die) The flange mounts flush against a plywood firewall or tab and the nut is screwed on from the other side. A plywood key is glued into the firewall next to the hole and engages into the flange notch to prevent rotation while tightening the nut.
Wish I had a camera, then I wouldn't need a thousand words