What is the diameter of a stock ford roller ?
Did they change through their production?
Latest print T-673A dated 2/15/23 shows "Rough Cut .685-.695" and "Grind .672-.6775".
I cannot answer the second question because I currently cannot lay my hands on the "Record of Change" card for this factory number.
Be aware there is a bushing in the roller, factory number T-4456 "Bushing Commutator Roller Pin Sleeve"
Hope this helps.
Ron the Coilman
I don't think the diameter is real fussy. When we rebuilt timers years ago, I made new rollers from brass, slightly oversize. They worked just fine.