Chinese 300W DC spindle - is the spindle shaft grounded?

[HankMcSpank]

My digital calipers are playing up (pah, that's LIDL for you ....must get a new one asap!), but I reckon the shaft protuding out the top is about 8mm dia. (eg I have an oldham coupler that's got an 8mm bore & that fitted onto the top shaft very snugly).

So how does this normally work? .....presumably a bog standard 8mm ID bearing will fit over the shaft, but it won't be a press fit (whereas the original fan that came fitted was a press fit & actually took some prizing off!)...& presumably I'll need a press fit here? (at this point, I'm hoping 'press fit' is the right term......ie were the bearing doesn't just slide on, but needs to be coaxed on with some pressure) ...I therefore probably need a bearing a tad less than 8mm?!!!