Going from memory, after searching for said bolts while at Windber one year, for my son's War Eagle...I believe it was 5/16th...24 thread. I do recall they are fine thread for sure.
@Dr. Shop Teacher and his spare bolt can produced two of those elusive bolts for Cadman's clutch guard !
That's when I realized my Harbor Freight bolt assortment wasn't all I thought it was, as it had no fine thread bolts in it, lol.
@creed bennett please post up what you found, for confirmation.