This will be my collection of ballchain tools / attachments.
i purchased 4.4 mm ballchain from homehardware and it works with this. #10 ballchain
for the mini steppers use the original file. fits right on them.
also it works with the smaller ballchain like for cealing fans really good.
could be used in conjunction with https://www.thingiverse.com/thing:445171
if you need to seamlessly join ballchain together the metal clips probably work best , a peice of wire might work well or even a string if you really needed to.