The search here doesn't operate like other searches, I don't think it could find it's self. Without seeing the mototr what I would do is tap a hole in the end of the shaft and attach the blade with washers and screw. Reverse thread would be good that way as it turns the screw tightens.

I've never seen the info your talking about here. The wheels already been invented, just look at tools that already have it figured out and do something similar.