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Hi Joel,

Indeed, there are lots of things you can do when you
are spooling thread, twine, or string.

First, the thread has a twist to it, which makes it
naturally want to lay with the help of the twist. If your
universal wind is in the right direction the thread's
twist will give the thread a tendency to roll away from
slipping.

And, second, the thread has a lot of friction to it to
prevent it from slipping.

Wire, on the other hand, has neither. It wants to lay
straight, and any deviation from a straight pull between
the point the wire lays, and the source of the wire, will
cause it to slip.

My early attempts were to try to follow the way the thread
mills wound thread onto the cones you describe, and it was
a miserable failure. Works great with thread, but with
wire, it all bunches up in a lump in the middle of the form,
with little staying on the sides.

I then went to look at what the radio guys did with home
made RF chokes, typically made from Litz wire and with a
"PI" wind, which is another name for the universal wind.

They used a stylus to direct the wire to lay in the proper
position on the coil.

That didn't work too well either, as enamel wire was too
slippery.

In the end, I always covered the coil form with double stick
tape so that the start of the wind was nicely supported, and
I also ran the wire through a solution of alcohol and rosin
to give it a tackiness that was necessary to make it stay
put until it was actually locked in place by subsequent turns
of the winding.

Tektronix actually bought their wire pre-treated with a satin
finish, and some friction enhancing agent. Try and buy some
of that stuff!

-Chuck Harris

Joel B Walker wrote: