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Toroid Winding Question

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Clark Macaulay KE4RQ

Toroid Winding Question

Perhaps this question has been raised before, but I haven't been able to find it in the archives nor in the manual.

I've built a K1 (words fine) and am now building a K2. Yesterday, while finishing one of the first toroids in kit, I noticed one of the turns had crossed over the previous one, so I began to unwind it. Then I noticed that the wire had the enamel nicked in several places and chose to replace it.

In thiking over what might have happened, wondered if I may have been pulling the winding too tight. Currently, I'm "pushing" the wire through the center of the core rather than "pulling" it so as to keep it away from the core to minimize scratching it. Obviously, though, it's not possible to know if the winding has been scratching in making the bend around inside.

So, my question is, to quote Shakespear, is my concern "much ado about nothing"? Am I winding them too tight (I noticed there are LONG leads after winding that could indicate the turns are too tight)?

73 de Clark KE4RQ
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Brett gazdzinski-2

RE: Toroid Winding Question

In my case, I wound them tight, and reduced the amount of wire
used so I did not have so much extra after the torod was done.
Some cores scrape the wire, I tried to use a bit more caution
but still had some scrapes, it does not matter, they don't short out.

I wound all my toroids with one extra turn, as the first pass
through the core counts as a turn (I did not know that), the rig
actually seemed to work better before I unwound one turn off
every toroid and re-did the alignment/calibration.

I would doubt the tightness makes much difference other than
looks, as one turn more or less did not seem to make any big difference
in my K2.

Brett
N2DTS

> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of Clark Macaulay
> Sent: Thursday, July 05, 2007 8:27 AM
> To: ElecraftList
> Subject: [Elecraft] Toroid Winding Question
>
> Perhaps this question has been raised before, but I haven't
> been able to find it in the archives nor in the manual.
>
> I've built a K1 (words fine) and am now building a K2.
> Yesterday, while finishing one of the first toroids in kit, I
> noticed one of the turns had crossed over the previous one,
> so I began to unwind it. Then I noticed that the wire had the
> enamel nicked in several places and chose to replace it.
>
> In thiking over what might have happened, wondered if I may
> have been pulling the winding too tight. Currently, I'm
> "pushing" the wire through the center of the core rather than
> "pulling" it so as to keep it away from the core to minimize
> scratching it. Obviously, though, it's not possible to know
> if the winding has been scratching in making the bend around inside.
>
> So, my question is, to quote Shakespear, is my concern
> "much ado about nothing"? Am I winding them too tight (I
> noticed there are LONG leads after winding that could
> indicate the turns are too tight)?
>
> 73 de Clark KE4RQ
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>

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Don Wilhelm-3

Re: Toroid Winding Question

In reply to this post by Clark Macaulay KE4RQ

Clark,

Scraped wire can lead to shorted turns. The core is not conductive, but
if adjacent turns short to one another, failure will result.

You are doing it right by pushing the wire through the center rather
than pulling it. To keep the turns tight, dress the wire around the
outside of the core with your finger, then push the wire through the
center until a small loop remains - you can then snug the turn by
pulling it the rest of the way through and no scraping should result.

Those ferrite cores do have sharp abrasive corners - it is the nature of
ferrite cores and one of those things we have to deal with.
The powdered iron cores have smooth corners and do not create the
scraped enamel problem.

73,
Don W3FPR

Clark Macaulay wrote:
> Perhaps this question has been raised before, but I haven't been able to find it in the archives nor in the manual.
>
> I've built a K1 (words fine) and am now building a K2. Yesterday, while finishing one of the first toroids in kit, I noticed one of the turns had crossed over the previous one, so I began to unwind it. Then I noticed that the wire had the enamel nicked in several places and chose to replace it.
>
> In thiking over what might have happened, wondered if I may have been pulling the winding too tight. Currently, I'm "pushing" the wire through the center of the core rather than "pulling" it so as to keep it away from the core to minimize scratching it. Obviously, though, it's not possible to know if the winding has been scratching in making the bend around inside.
>
> So, my question is, to quote Shakespear, is my concern "much ado about nothing"? Am I winding them too tight (I noticed there are LONG leads after winding that could indicate the turns are too tight)?
>
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KBG Luxford

Re: Toroid Winding Question

In reply to this post by Clark Macaulay KE4RQ

With respect to toroid sharp edges, should one rub some "wet and dry"
abrasive paper around the edges before winding?

How about winding plumbers' pipe thread teflon tape around the core
before winding?

I am about to resume work on my K2!

Happy July 4

Kevin
VK3DAP / ZL2DAP
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Matthew Murphy Palmer

Re: Toroid Winding Question

Not sure about hand sanding, but i know grinding ferrite is a tricky
process, I haven been designing flyback transformers of late and grinding
the gap in ferrite cores has resulted in many cracked and broken cores, i
would assume if you are meticulous and careful hand sanding is probably ok.

Matt
KD8DAO

KBG Luxford writes:

> With respect to toroid sharp edges, should one rub some "wet and dry"
> abrasive paper around the edges before winding?
>
> How about winding plumbers' pipe thread teflon tape around the core before
> winding?
>
> I am about to resume work on my K2!
>
> Happy July 4
>
> Kevin
> VK3DAP / ZL2DAP
> _______________________________________________
> Elecraft mailing list
> Post to: [hidden email]
> You must be a subscriber to post to the list.
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>

Tom Hammond-2

Re: Toroid Winding Question

In reply to this post by KBG Luxford

Hi Kevin:

Probably more effort than it's worth.

I have tried running a 'beveling' drill bit around the inner edges,
and several other schemes, but not sure it's much help.

For the relatively few ferrite cores in the kit, I would urge the
careful application of restraint while winding and not worrying about
it from there on.

We hear very little(!) from builders regarding actual problems from
shorted turns, so it's obviously not a significant problem... other
than a source for worry for some builders. If it were a bulldog, his
bark would be worse than his bite!

Cheers,

Tom Hammond N0SS

At 08:19 07/05/2007, KBG Luxford wrote:

>With respect to toroid sharp edges, should one rub some "wet and
>dry" abrasive paper around the edges before winding?
>
>How about winding plumbers' pipe thread teflon tape around the core
>before winding?
>
>I am about to resume work on my K2!
>
>Happy July 4
>
>Kevin
>VK3DAP / ZL2DAP
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
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Geoffrey Mackenzie-Kennedy-2

Re: Toroid Winding Question

In reply to this post by KBG Luxford

A single layer of plumber's teflon tape has worked well for me and appears
to have little if any effect on coil Q etc. The stuff has a mind of its own
though when you use it :-)

73,
Geoff
GM4ESD

KBG Luxford <[hidden email]> wrote:

> With respect to toroid sharp edges, should one rub some "wet and dry"
> abrasive paper around the edges before winding?
>
> How about winding plumbers' pipe thread teflon tape around the core before
> winding?

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Don Wilhelm-3

Re: Toroid Winding Question

In reply to this post by KBG Luxford

Kevin,

I have not tried it, but I believe the ferrite material is harder than
the 'wet and dry' paper.

All in all, I do not believe any prep work on the cores is worth the
effort. Just remember to *push* the wire through the center rather than
trying to pull it through. Using your finger to form the wire around
the *outside* of the core as each turn is placed will result in a neater
and tighter winding than all the pulling in the world.

Try it on 2 toroids - then wind your 3rd - after that you too can call
yourself an expert. Many folks seem to have some anxiety about toroids
until they have wound some. It is not necessarily the most pleasant
task, but it is really easy - just do it.

If you have a long wire to deal with, start in the middle, wind half the
turns and turn it over and wind with the other half.
As soon as you put a wire through the center of the core, start counting
- that is one turn. One full winding around the core is two turns.

73,
Don W3FPR

KBG Luxford wrote:

Mychael Morohovich

Re: Toroid Winding Question

In reply to this post by Clark Macaulay KE4RQ

Hi, Kevin-

Some of the ferrite cores can be a bit rough around the edges. When I
encounter a batch that exhibits this characteristic, I use a drill-bit to
clean up the burr prior to winding. Pick a drill-bit of a size
substantially larger than the toroid's inner diameter, and spin its tip
back and forth a few times in the toroid's hole. You should fine that the
burr comes off easily. I don't usually have trouble with the OD of the
toroid, but in that case you could use some fine sand paper.

73,

Mychael / AA3WF
K2 #1025

> With respect to toroid sharp edges, should one rub some "wet and dry"
> abrasive paper around the edges before winding?
> Kevin
> VK3DAP / ZL2DAP

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John Young-11

Re: Toroid Winding Question

In reply to this post by Don Wilhelm-3

I've not had a problem - yet,

Has anyone tried painting the rough areas with a little clear nail polish?
Seems simpler than trying to sand or drill and should not affect the inductance.

73 John
WA8KNE

> Clark Macaulay wrote:
> > Perhaps this question has been raised before, but I haven't been able to find it in the archives nor in the manual.
> >
> > I've built a K1 (words fine) and am now building a K2. Yesterday, while finishing one of the first toroids in kit, I noticed one of the turns had crossed over the previous one, so I began to unwind it. Then I noticed that the wire had the enamel nicked in several places and chose to replace it.
> >
> > In thiking over what might have happened, wondered if I may have been pulling the winding too tight. Currently, I'm "pushing" the wire through the center of the core rather than "pulling" it so as to keep it away from the core to minimize scratching it. Obviously, though, it's not possible to know if the winding has been scratching in making the bend around inside.
> >
> > So, my question is, to quote Shakespear, is my concern "much ado about nothing"? Am I winding them too tight (I noticed there are LONG leads after winding that could indicate the turns are too tight)?
> >
> _______________________________________________
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--
John D Young
WA8KNE
ETC USN retired
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Stuart Rohre

Re: Toroid Winding Question

You can reinsulate the wire by painting it with clear nail polish. In
fact, the cores are not a concern as they are an insulating material. The
bare wire touching the core is not a concern, a bare wire touching an
adjacent winding is what to avoid. You do not have to have the turns pulled
so tight against the cores that you are abrading the insulation. Gently
pushing or pulling them thru should be fine. I sometimes make my cores
"look better" by pushing gently on the winding to make the wires lie more
flat against the core. This is safely done with the fleshy part of the
thumb.

Stuart
K5KVH
----- Original Message -----
From: "John Young" <[hidden email]>
To: <[hidden email]>
Cc: "ElecraftList" <[hidden email]>; "Clark Macaulay"
<[hidden email]>
Sent: Thursday, July 05, 2007 1:36 PM
Subject: Re: [Elecraft] Toroid Winding Question

> I've not had a problem - yet,
>
> Has anyone tried painting the rough areas with a little clear nail polish?
> Seems simpler than trying to sand or drill and should not affect the
> inductance.
>
> 73 John
> WA8KNE
>
>
>> Clark Macaulay wrote:
>> > Perhaps this question has been raised before, but I haven't been able
>> > to find it in the archives nor in the manual.
>> >
>> > I've built a K1 (words fine) and am now building a K2. Yesterday,
>> > while finishing one of the first toroids in kit, I noticed one of the
>> > turns had crossed over the previous one, so I began to unwind it. Then
>> > I noticed that the wire had the enamel nicked in several places and
>> > chose to replace it.
>> >
>> > In thiking over what might have happened, wondered if I may have been
>> > pulling the winding too tight. Currently, I'm "pushing" the wire
>> > through the center of the core rather than "pulling" it so as to keep
>> > it away from the core to minimize scratching it. Obviously, though,
>> > it's not possible to know if the winding has been scratching in making
>> > the bend around inside.
>> >
>> > So, my question is, to quote Shakespear, is my concern "much ado
>> > about nothing"? Am I winding them too tight (I noticed there are LONG
>> > leads after winding that could indicate the turns are too tight)?
>> >
>> _______________________________________________
>> Elecraft mailing list
>> Post to: [hidden email]
>> You must be a subscriber to post to the list.
>> Subscriber Info (Addr. Change, sub, unsub etc.):
>> http://mailman.qth.net/mailman/listinfo/elecraft
>>
>> Help: http://mailman.qth.net/subscribers.htm
>> Elecraft web page: http://www.elecraft.com
>>
>
>
> --
> John D Young
> WA8KNE
> ETC USN retired
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>