Smitty Two wrote in message
news
In article ,
"N_Cook" wrote:

Smitty Two wrote in message
news
In article ,
"N_Cook" wrote:


With pulling off the spool axially and vertically don't you get
problems
when the lead-out reaches the top of the supply spool? compared to
pulling
off
axially.

Not sure whether you meant to say "as opposed to pulling off
radially?"
But in any case, I think that the way it's done on our winder provides
*consistent* tension. As I mentioned, a larger diameter spool does
cause
problems, though.

This pic isn't very clear, but it's a "whisker disk" that is supposed
to
sit on top of the spool to dampen oscillations as the wire dereels. We
found it to be counterproductive.

http://members.cox.net/prestwich/winder015.jpg


But what happens for the when the spool take-off reaches the very
uppermost
turn and the wire is rubbing along the internal face of the spool and
being
pulled through a softened right angle at the the spool rim ?

Well, thirty five years ago I might have been able to analyze and
quantify the physics of that. All I can say now is that it doesn't pose
a problem. The wire is *always* being dragged against the the endcap of
the spool, at varying angles of course, but if the set-up does have
drawbacks they seem to be minimal. I think that without a motorized
dereeler and a sophisticated system to monitor slack and adjust dispense
and take-up speeds, this is the best approach.


The spool must be wound in a radial sense at manufacture, so I assumed it
was best to take it off radially.
If mounted vertically and pulled off vertically then its not just the
uppermost take-off rubbing against the spool end but at the lower end, on
every other layer, you are pulling against the remaining lay of wire.

My method is not ideal , hence this thread. I chose mounting vertically and
pulling off horizontally for minimum pull off variable tension.
Mounting the spool on a pair of good quality ball races and then adding an
ex-VCR slip clutch pair over the top. One runs with the spool and the other
sprung tied back to frame and small weight added to activate the
braking/slip.
That works very well but it leaves the problem of variable lay pull-off
tension from the spool at these small wire gauges.

I see I have to probably increase to 3 slip/brakes. Existing exVCR slip with
very little weight , little more than a brake, and the main back-tension
governed by a mix of your felted clothes pegs and lightly sprung felted
discs, separated as far apart as practical to employ inherent slight
stretching in the wire, to even things out, as well as my existing dancer
arm and pulley.

Another minor problem is the final small pulley that delivers the wire to
the bobbin. Plenty of pulleys with good quality bearings salvaged from kit.
But they all the good quality ones have a groove at the join of the V of the
pulley, just the thickness of this wire, so useless for this purpose. I
assume as they are for rubber drive band use it is something to do with air
being trapped between pulley and rubber if no such groove. I may swap to
just a small piece of PTFE with a groove in it , extended on a moveable rod,
instead of a pulley for final delivery.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/