1860 TB farthings often show a week strike, they still suffered with similar probs till about 1872 when they started to produce a better end product , although there was a steady improvement from 1860 onwards.
The major problem was the beaded border and the relative hardness of the bronze coupled with the size of the farthing , steady progress was made for 12 years or so .
Pennies and halfpence seemed to suffer less .