Using 1/4” 3M blue fine line stencil tape, I was able to follow the old outline of the stripes
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Nice. That is exactly what I were tinking to do too. Not myself I mean as, I'm too screwed up these daz. But now You can roll, spray or brush it on. However, yeah, ya missed the curve and drove across the dammed street! .
Wait! Edit! Yeah, dat's a chevron styled tip which is also on the 50's Junior 24 and 20" balloon bikes, U No Get the fancy dancy fender tip and redirected striped curves on em, , never mind.
Alternatively, as mentioned: If you could mount a fender (fender brackets) on an axel centered properly, U could mimic the rollers they used, hold hand steady or in fixed position. Or, Rig up a jig to maintain the roller brush, or on the side of large oversized fork, and turn fender while applying paint filled roller brush.
I mean, unless it's got that special curve on Schwinn's post war 'Fancy' models any fender too. Surely rolling them while applying a stripe or 3, same as Schwinn's photo in factory, round rolling templates that's not special or a trade secret, it's how everybody did it, for long, long time prior to 40's Common equipment in a factory paint shop. IDK but wouldn't be 'ingenious' 19th century practice too. Yet maybe Egyptians were to stupid, unable to use mud guards, and dumb to have had paint stripes on their wheels by just spinning em .