charity shop find earlier this week was a Swan/M.T. s.f. in mid blue, model No. 3170 - not particularly exciting until I dip tested the nib, which turns out to have some very creative flex, and one of the smoothest Swan nibs I've found.
The nib imprint says SWAN - 1 - K - 14C-585, and I'm guessing date wise from somewhere in the 1950s ............... I think I've read somewhere on the FPN that the K stands for Kugel, which is a German word referring to the ball like tipping material so shaped to give good writing result however the nib is orientated.
Of course I might have this wrong entirely - can someone help to shed light on my suggestion, please.