Found this on warflag.com:
To create pole cords you will need a few stands of copper wire (from a few feet of stripped speaker wire). Put a few strands together (the amount will depend on scale) and anchor one end of the bunch to your painting desk with a thumb tack (drawing pin). Hold the other end of the wires in the chuck of an electric screw driver or variable speed drill. Rotate the drill slowly while pulling out he slack and holding the bunch taught until the strands are tightly bound. What you should have at this point is something that looks remarkably like scaled down rope. Prime it black and dry brush the appropriate color. This also makes good reigns for chariots and horses etc. It keeps it shape well. For the French flags in the 18th century up to the American Revolution, don't use pole cords. They had scarves. For the War of Spanish Succession use the pole scarves displayed with the French of the American Revolution period (Small white strips above the colonels colors).
I also use thin copper wire for the flag ropes. 3-4 Wires twisted together are sufficient. At the ends I put a small drop of glue as a tassel. After drying, I tie the ropes to the flag and then paint them.
See my "Prussian Inf Shoulder Arms"-Contribution from 2019 as exampel. But I used only two wires for the prussian flag you can see there..