Rotating Ball nut

[drumsticksplinter]

I' ve come up with an idea to house the bearings for this rotating nut idea:



If I went with Jonathan's suggestion of 7207 angular contact bearings with an OD = 72mm, then I could probably machine this housing myself on my lathe. Once bored out I should be left with a 6.5mm wall thickness, do you think this will be sufficient? After all, the main force acting on this setup will be axial. I was looking at the 7008 bearings with 68mm OD, which would leave me with more wall thickness, but I can't seem to find anyone selling them?? Failing that, would I get away with deep groove bearings?? There seem to be a much better size selection.