If the fork is threadless, and both mine are, then you'd need to change the headset from threaded to threadless.
Threadless 1" headsets are not the most plentiful of items, but a number of companies still make them from people like Ritchey, Cane Creek / Tange right up to Chris King.
Both my Raleigh and Rourke have Ritchey headsets, although they are different models.