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. 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
?

"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.

remove ch100-5 to avoid spam trap

bz wrote in message
98.139...
"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.

remove ch100-5 to avoid spam trap

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.

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

"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.

In article ,
"N_Cook" wrote:

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. 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
?

I've wound a coil or two; we make guitar pickups. Tensioning requires a
bit of logic and science, but a healthier dose of black magic. We use 42
AWG almost exclusively, and put somewhere between 5000 and 8000 turns on
a given bobbin.

There are happy days when you get 95% yield and annoying days when you
get 10%. There are several components to the dereeling and tensioning
process. I can take some pics of our machine or some copies from the
relevant operator's manual pages in the next day or two if you like,
with further observations.

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

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. 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
?

I've wound a coil or two; we make guitar pickups. Tensioning requires a
bit of logic and science, but a healthier dose of black magic. We use 42
AWG almost exclusively, and put somewhere between 5000 and 8000 turns on
a given bobbin.

There are happy days when you get 95% yield and annoying days when you
get 10%. There are several components to the dereeling and tensioning
process. I can take some pics of our machine or some copies from the
relevant operator's manual pages in the next day or two if you like,
with further observations.

That would be very helpful.
Can you upload to a site somewhere? if by email, I will have to relay an
email
account/address to you that does not have filters on it.

I've had another google and not found anything useful.

There is nothing wrong with the spool layering , it is just the natural
marginal wedging that occurs with on unwinding, not overlaps , but just
slight variation of a couple of ounces that would not matter if using 8oz
of back tension or more for a thicker gauge, but 2 oz is too critical.

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

N_Cook wrote:

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. 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
?


I don't know about that how ever, at work we deal with small wire and
conductor in the area's of 40 AWG etc.. and 2 difference systems are used..
One uses a small lever (catenary) arm with a small disc roller on the
end of the arm along with an eyelet to keep it in the roller.
When the wire is pulled, it pulls down on the arm which has a spring
as part of a strap that goes around a drum that is an integral part of
the pay off shaft the supply of wire is loaded on.

The strap has a rawhide pad on it.. the pulling of the arm pivots on a
shoulder bolt, the other end opens the strap to release the braking.
Putting on a tiny air piston with speed bleeders on both ends help
in damping the oscillation.

The other system is just about the same how ever, we have a DC motor
attached to the shaft with a dancer circuit. The centenary arm has a
small POT on it that drives the DC regen drive to maintain position of
the arm which maintains constant tension through out on the take up end.

This works great for very fine wire and all we do is adjust the spring
on the arm via a thumb screw and lock nut on the threads.

The motors are 1/10 HP PM units.

The pot's are optical types, so the movement in the shaft has very
little drag and are smooth .

The electronics for the Pot sensing has trims on it to adjust for
delay, Lead, sensitivity etc..

http://webpages.charter.net/jamie_5"

In article ,
"N_Cook" wrote:

Smitty Two wrote in message
I can take some pics of our machine or some copies from the
relevant operator's manual pages in the next day or two if you like,
with further observations.

That would be very helpful.

http://members.cox.net/prestwich/winder001.jpg
http://members.cox.net/prestwich/winder003.jpg
http://members.cox.net/prestwich/winder008.jpg
http://members.cox.net/prestwich/winder011.jpg

This is a motorized winder, obviously, so take whatever is applicable
for your machine. We found that the tiniest details are important. For
example:

Dereeling counterclockwise, on our machine, makes a significant
difference.

Spool diameter is important. Too large, and the wire gets tossed around
too much on its way from curved to straight.

It's tempting to wind with the minimum possible tension, but the result
will be loose coils, which may or may not be an issue in your
application. Our dancer arm is set to the minimum, but the wire also
goes through three felt pinchers.

Placement of felt tensioning pads is widely adjustable, and we only
found the best positioning after much experimentation. We have one near
the dereeler and two close to the bobbin.

The bobbin should be dead smooth, obviously. No burrs allowed, and it
has to run true.

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

Smitty Two wrote in message
I can take some pics of our machine or some copies from the
relevant operator's manual pages in the next day or two if you like,
with further observations.

That would be very helpful.

http://members.cox.net/prestwich/winder001.jpg
http://members.cox.net/prestwich/winder003.jpg
http://members.cox.net/prestwich/winder008.jpg
http://members.cox.net/prestwich/winder011.jpg

This is a motorized winder, obviously, so take whatever is applicable
for your machine. We found that the tiniest details are important. For
example:

Dereeling counterclockwise, on our machine, makes a significant
difference.

Spool diameter is important. Too large, and the wire gets tossed around
too much on its way from curved to straight.

It's tempting to wind with the minimum possible tension, but the result
will be loose coils, which may or may not be an issue in your
application. Our dancer arm is set to the minimum, but the wire also
goes through three felt pinchers.

Placement of felt tensioning pads is widely adjustable, and we only
found the best positioning after much experimentation. We have one near
the dereeler and two close to the bobbin.

The bobbin should be dead smooth, obviously. No burrs allowed, and it
has to run true.

Many thanks for that.
Seems more black arts than science. I assume the black fibrous block under
the arm in pic 008 is someone's retrofit damper like the Millenium Bridge in
London.
http://www.taylordevices.com/papers/damper/damper.html

I think I would make the sprung arm out of lighter materials as I would only
need it for 40AWG/45SWG type gauges and so less inertia there.
Do you find a problem with dirt or grime on the felt pads causing
irregularity problems at these light tensions ?

I was wondering if a servo system for spool unloading to zero tension is a
way to go. Inductively or optically, somehow monitoring the sag in an
unsupported section of the supply wire. When in optimal band then spool rate
say 5 second average speed. More sag then proportional down to zero speed
and too little sag then proportional up to some system limit.


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

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

Smitty Two wrote in message
I can take some pics of our machine or some copies from the
relevant operator's manual pages in the next day or two if you like,
with further observations.

That would be very helpful.

http://members.cox.net/prestwich/winder001.jpg
http://members.cox.net/prestwich/winder003.jpg
http://members.cox.net/prestwich/winder008.jpg
http://members.cox.net/prestwich/winder011.jpg

This is a motorized winder, obviously, so take whatever is applicable
for your machine. We found that the tiniest details are important. For
example:

Dereeling counterclockwise, on our machine, makes a significant
difference.

Spool diameter is important. Too large, and the wire gets tossed around
too much on its way from curved to straight.

It's tempting to wind with the minimum possible tension, but the result
will be loose coils, which may or may not be an issue in your
application. Our dancer arm is set to the minimum, but the wire also
goes through three felt pinchers.

Placement of felt tensioning pads is widely adjustable, and we only
found the best positioning after much experimentation. We have one near
the dereeler and two close to the bobbin.

The bobbin should be dead smooth, obviously. No burrs allowed, and it
has to run true.


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.

One thing i have learnt is the use of a small force gauge as used in
checking slip clutches etc on VCRs.
Mine is 0 to 50gm Halda / Haldex of Sweden, just make a loop in the end of
the wire to hook into and pull for a bit, to check for tension and
consistency on the dial.

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

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

In article ,
"N_Cook" wrote:

Many thanks for that.
Seems more black arts than science. I assume the black fibrous block under
the arm in pic 008 is someone's retrofit damper like the Millenium Bridge in
London.
http://www.taylordevices.com/papers/damper/damper.html

Ha, I hadn't heard that bridge story! The little scrap of scotchbrite
pad is to soften the metallic clang of the dancer arm, but in normal
operation it doesn't hit there, anyway.


I think I would make the sprung arm out of lighter materials as I would only
need it for 40AWG/45SWG type gauges and so less inertia there.
Do you find a problem with dirt or grime on the felt pads causing
irregularity problems at these light tensions ?

The pads are replaced as needed, but they don't tend to collect dirt.


I was wondering if a servo system for spool unloading to zero tension is a
way to go. Inductively or optically, somehow monitoring the sag in an
unsupported section of the supply wire. When in optimal band then spool rate
say 5 second average speed. More sag then proportional down to zero speed
and too little sag then proportional up to some system limit.

I think the less technology, the better. We built a custom take-up
winding machine for a fibre optic manufacturer, and it was fairly
sophisticated, with a PLC controlling everything. If I had to do it
over, I'd just use a dancer arm...

I think one key to the success of this machine is the substantial
distance from spool to bobbin. Nowhere is there any slack wire beyond
the idler pulley, but the distance and widely spaced tensioners may
allow some imperceptible stretching, and of course the idler pulley
moves up and down slightly on the end of the dancer arm, which moderates
dereeling variations.

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 ?

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.

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/

In article ,
"N_Cook" wrote:

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.

I'm not quite following your last paragraph, here. Why are the good
quality guide pulleys useless? Isn't the guide groove just what you
want? Sounds like what we have at the bobbin end. What do you mean by
them being for rubber drive band use?

BTW, how are you handling the traverse motion to lay the wire neatly
along the bobbin's length?

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

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.

I'm not quite following your last paragraph, here. Why are the good
quality guide pulleys useless? Isn't the guide groove just what you
want? Sounds like what we have at the bobbin end. What do you mean by
them being for rubber drive band use?

BTW, how are you handling the traverse motion to lay the wire neatly
along the bobbin's length?

Most of the pulleys , that have high quality bearings, ie run true have come
from tape players or VCRs. It seems that along with the high quality
bearing, they have this very small groove, that honestly I've never noticed
before.

The pulley rim is V in section but instead of coming to a point at the
bottom of the V they have a tiny slot perhaps 0.1 to 0.2mm which grabs on
wire of 0.07mm diameter, due to slight imperfections or whatever.

The traverse speed and change direction is automatic and works very well
once the infinitely variable gearing is set and end settings positioned.
There is a bit of a kick due to the PTO change-over action but a kick to
slacken wire supply, rather than tighten which would be disastrous, and I
can compensate for that , as manual , by slowing the rotation down just
prior to flip over and hand brake slightly..


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

"N_Cook" wrote in
:

The pulley rim is V in section but instead of coming to a point at the
bottom of the V they have a tiny slot perhaps 0.1 to 0.2mm which grabs
on wire of 0.07mm diameter, due to slight imperfections or whatever.


can you run a rattail file along there to widen/remove the groove?
How about wrapping a few layers of TFE tape around the pulley and filling
in the groove?

Shapelock aka Friendly plastic could be used to mold a 'cover' for the
pulley. Heat it with a hot air gun or hot water, it turns clear and
mold-able. It sticks to other plastics. When it cools it is nylon hard and
opaque white. I have used it to fix broken nylon gears in a printer and a
broken slide bracket in my wife's sewing machine.



--
bz 73 de N5BZ k

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

remove ch100-5 to avoid spam trap

I can wind a fish line.My fishing reel machine automatically does it for
me.
cuhulin

bz wrote in message
98.139...
"N_Cook" wrote in
:

The pulley rim is V in section but instead of coming to a point at the
bottom of the V they have a tiny slot perhaps 0.1 to 0.2mm which grabs
on wire of 0.07mm diameter, due to slight imperfections or whatever.


can you run a rattail file along there to widen/remove the groove?
How about wrapping a few layers of TFE tape around the pulley and filling
in the groove?

Shapelock aka Friendly plastic could be used to mold a 'cover' for the
pulley. Heat it with a hot air gun or hot water, it turns clear and
mold-able. It sticks to other plastics. When it cools it is nylon hard and
opaque white. I have used it to fix broken nylon gears in a printer and a
broken slide bracket in my wife's sewing machine.



--
bz 73 de N5BZ k

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

remove ch100-5 to avoid spam trap


I tried plumber's PTFE and it failed.
Had another hunt through my collection of salvaged pulleys and from about 20
they all had this tiny groove just where I don't need it.
Never previously realised, because it is such a tiny groove, that all good
quality small pulleys , plastic, brass or aluminium have this groove.
Still not found the funtional reason for it.

Took some advice from a proper mechanical engineer on how to best tackle
turning my own small 8mm diam x 3mm PTFE pulley with a straight (un grooved)
V cut , and will go down that root ;-)

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

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

remove ch100-5 to avoid spam trap


I tried plumber's PTFE and it failed.
Had another hunt through my collection of salvaged pulleys and from about 20
they all had this tiny groove just where I don't need it.
Never previously realised, because it is such a tiny groove, that all good
quality small pulleys , plastic, brass or aluminium have this groove.
Still not found the funtional reason for it.

Took some advice from a proper mechanical engineer on how to best tackle
turning my own small 8mm diam x 3mm PTFE pulley with a straight (un grooved)
V cut , and will go down that root ;-)

Just a little speculation about the groove:
It may be that if the pulley is transporting something like mag tape
this groove is necessary to keep an air bubble from forming and
"flying" the tape.

It would not be difficult to round out the bottom of an existing
pulley with a lathe-like setup. I save old drill bits to make special
tools for that sort of thing.

John Ferrell W8CCW
Beware of the dopeler effect (pronounced dope-ler).
That's where bad ideas seem good if they come at you
fast enough.

John Ferrell wrote:

Just a little speculation about the groove:
It may be that if the pulley is transporting something like mag tape
this groove is necessary to keep an air bubble from forming and
"flying" the tape.

It would not be difficult to round out the bottom of an existing
pulley with a lathe-like setup. I save old drill bits to make special
tools for that sort of thing.

You dont want the bottom of a pulley for square section belts to be
rounded, the drive comes from the sides of the belt. Like the vee belt
on a car alternator, when it wears enough for the belt to bottom out on
the pulley, it stops driving.

The slit is there so that the flat sides make correct contact

Ron(UK)