Wheel bearings
 

I have access to a bunch of sealed bearings for dirt cheap, they look something like these:

http://www.jensonusa.com/store/imgWr..._10.jpg&type=2

Can these be used on hubs?
And if so how?

They can be used on hubs designed for cartridge style bearings and then only if they are the specific size used in that hub..I don't know of a way of retrofitting them into a hub designed for loose ball bearings.

Darn.
Loose balls it is then...