"N_Cook" wrote in
:

I think a cross-wired memory effect has come into play.
That pair of discs is what I've seen on a sewing machine and memory
transfered to coil-winder m/c so probably have no recollection of what
that Douglas mechanism was. But I do remember having to use fingers for
back-tension as the proper mechanism , whatever it was, was unreliable.

One or more turns around a shaft might do the job.
You might tear up an old hard drive and use the supports and bearing for
the platters for the shaft variable drag on the shaft could set the
tension for you. Somewhat similar to the drag on a tape machine.

Another idea, how about the variable drag on a fishing reel?
Off load your wire onto the reel.




--
bz

please pardon my infinite ignorance, the set-of-things-I-do-not-know is an
infinite set.