Originally Posted by
DesertRat
You lost me at sheet of glass. Are you using a powder abrasive or something?
I found that the smoothest and longest-lasting diff I could produce was with nitride balls that I reuse, standard steel rings as opposed to lightweight ones, and a thrust bearing to hold it all together. Its expensive only once.
If you can get the standard rings flat and run both the inner and outer diff ball holes you will get a very smooth diff...the more diff balls you can use the smoother it will be.