[Sneeck]

I don't think it is wise to use a m4 bolt through such a small axle. I've never had a problem with my ue cup's holding on the diff's. Make sure the flat spot of the axle is wide enough for the screw head to sit on and use a little blue locktite.

(DON'T use the red stuff, it's a pain in the butt to remove later and will most likely strip the screw then get the screw out)


Edit;

Take a dremel and flatten the shaft so the set screw's sit on the flat spot. This should hold them fermly in place.