Dear Friends,
I simply cannot understand, that 70 years were not enough for invent the THIRD hole in the reel?!
When you have another upwinding hole on the opposite side, you can very quickly, and absolute safely roll up the lines, with a "bycicle-driving-like" movements with your left and right pointer fingers.
(You can easily drill the third hole: buy a 20 mm dia "crown drillhead", and some drops of water... )
I made a number of different designs: First ones made of open reel taperecorder's reel, still in 1969, now I can collect empty filament-reels as raw material from 3D printer colleagues: very strong, water clear, machinable by discsaw, lathe, milling machine and crown-drill. Beautifully gluable with some drops of chloroform... (It is Polycarbonate)
On demand I put photos up, just ask me!
istvan