One of the more intractable problems facing the fountain pen restorer is the over-and-under feed. Considering that it is just a forked piece of rubber, it works better than might be expected, sometimes with the help of a piece of twisted silver wire in Swan eyedroppers.
The difficulty is that, delicate things to start with, the passage of a century or more with all its vicissitudes means that many are broken. There are no replacements except from other pens. Cannibalising parts from later black pens to rescue patterned ones is all very well, but all these century-and-more-old black hard rubber pens are precious and I believe that it is wrong to sacrifice one to save another.
It would not be all that difficult to reduce a redundant, more modern feed to fit the small aperture of these pens, but there are two difficulties. I would have no reliable means of splitting the feed so that it could perform the over and under function. Secondly, these old feeds are flexible and would appear to be made from a different grade of rubber from later feeds.
What is to be done? Though it would take some experimentation, I believe I could shape a later feed to fit under the nib and fit the narrow aperture of the section. The original feed channels would be retained. The pen could then be used for writing once again but it would lose originality. Collectors might say that it would be better to leave the pen as it is. That’s a valid point of view but many of these earlier 20th century nibs are crying out to be used. They are beautifully made, precise and often flexible, for those who value that attribute.
Of course I have not exhausted all the possibilities of producing replacement over-and-under feeds. There may be other materials or sources of soft rubber that I am unaware of. I have confined myself to things that I can do. Others, with greater skills and ingenuity might come up with a better solution.