Originally Posted by
rhenning
Old English bikes used British Whitworth threads which is a completely different system. Roger
+1 this. Many older British bikes, especially at the low-end and utility bikes, used Whitworth thread headsets (1" x 26tpi 55° thread angle). "English" thread headsets are 1" x 24tpi 60° thread angle.
What specific bike are we discussing?
But the pressed fittings shouldn't be a problem. If the threaded cup and top nut are in reasonable condition, you could replace the lower stack with new parts (that's the part of the headset that takes the load and wears the most, after all) and retain the Whitworth upper stack to hold everything in place and in alignment.