I have tried to unscrew the forepart of my late father's Parker Challenger without success. I put it in to The Pen Shoppe in Brisbane, Australia, but their techie was also unable to separate the forepart from the barrel. Can anyone advise a solvent or other method that will unfreeze the two parts and allow them to be separated without doing damage to the plastic? I have thought about using a very fine, narrow-blade saw (if I can find one) but I cannot bring myself to risk wreaking such havoc on a lovely bit of kit; I would prefer to continue using it in dip-pen mode if I cannot get it open.
My father kept the pen as a sentimental keepsake but did not use it for the seventy years he owned it; I have attempted to have it repaired and to bring it up to refillable condition [the nib is superb] only since my father died.
Big ask, I suspect, but hope someone in the FPN community has met and solved this problem before.