"N_Cook" wrote in
:

My coil winder is from the 1920s and no manual and when I picked it up
in a very sorry state, it was minus the tensioning aparatus, so never
seen. This ETA hand winder is something like the Avo Douglas coil winder
but the manual for that is not very helpful on picture or description,
being part 30 lost in this pic, 50K
http://home.graffiti.net/diverse:gra...t/douglas2.jpg

I made up a workable back tensioner from VCR slip clutch, lightly sprung
pulley carrier etc but it is not very good for evening out the
variation due to unwinding very light gauge wire from the supply spool
giving a somewhat jerky back tension. It is many years since I was
hands-on a Douglas and have forgotten what the mechanism is. Anyone know
what the Avo system is or any other more reliable system. As far as I
remember it was a pair of discs that somehow the wire passed through and
the pressure between the discs was varied for different tension.

Many sewing machines use a similar system to set the thread tension.
You might adapt one from a sewing machine.

Also try looking up the patent applications for such devices, you might
finds something helpful.

I also
seem to remember that it too was not very good at the very lightest
gauge wire AWG40 / SWG45 and it was better to run through human fingers
rather than the discs. At only 1 or 2 oz back tension it would sometimes
grab onto the wire if contaminated or something and break the wire. But
there must be better than human finger back tensioner.
Is there a 2-stage spool supply process? so the wire is unwound to an
intermediary stage at near enough zero tension that then goes to the
winder ?






--
bz

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

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