[Pantera]

I am guessing but I would think it would make sense that who ever built the shaft or did the balance job on it would have put the paint stripes on. That way there would not be a mistake on the color for each length shaft.

The shafts would then be ready to go into the rack by color and the line worker could just grab the proper color when the car it went to came along.

So it makes sense to me that they would do it after building or doing the bal on the shaft while it was still in the lathe and they could spin it by hand to apply the color. I doubt that it was a brush that did it but a pad/swab with a tube of color behind it that was hanging just above the end that they put the color on?