I promised to proffer my guess on the mystery nib affixed to the Tuckaway I talked about in the posts Mystery Point/Counterpoint and Mystery Point/Counterpoint II. I had an unfair advantage, though, in this since I have a few more Sheaffer catalogs than just the one I showed the page from already. Take a look at the page from few years later below. It’s still an illustration without too much detail but I think it shows the shapes a bit better. Considering that the point has quite rounded shoulders and the nib does not exhibit too much curving inwards at the top leads me to my guess that the nib in question is a flexible coarse. Of course we’ll probably never know the truth.