I read in sci.electronics.design that Ian Stirling
wrote (in
) about 'wire size
question', on Fri, 8 Apr 2005:
In sci.electronics.design John Woodgate wrote:
I read in sci.electronics.design that Ian Stirling
wrote (in
) about 'wire size
question', on Fri, 8 Apr 2005:

Blowtorch to heat to dull red heat, and then wipe insulation off.

I'd like to see you do that with 30 gauge wire. For an encore, you could
do it with 46 gauge. (;-)

Actually, I do it regularly with .15mm wire (I don't know the guage)
Of course, you have to be able to set the blowtorch so that it's producing
a yellow flame that's not too hot, a lighter works well.

Oh, that's cheating. (;-) When you write 'blowtorch', you should mean
'blowtorch', 1000 C plus.

The almost cool flame of an alcohol burner is good, especially as it has
a large part of its volume that is chemically reducing.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

I read in sci.electronics.design that Jim Thompson
wrote (in
) about 'wire size
question', on Fri, 8 Apr 2005:

IIRC there's something called Formvar that will self-strip upon
application of a tinned iron.

Once upon a time, there was 'flux-enamelled' magnet wire, which was
really easy to solder, but the coating was fragile. Then there was
'solderable', which required an iron temperature substantially higher
than for normal soldering. But that gave off toluene diisocyanate, which
is poisonous if you breathe it for 20 years, so you had to use it under
extraction, and that made it fall out of favour.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

On Fri, 08 Apr 2005 13:10:24 -0700, Jim Thompson
wrote:


IIRC there's something called Formvar that will self-strip upon
application of a tinned iron.

---
And, in the process, tin the wire, changing its diameter...

--
John Fields
Professional Circuit Designer

Albert wrote in message
...
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

I know I can weigh it, provided it's not on a spool or motor winding
already.

My local electrical shop has a wire gauge, but it stops at 18 gauge.

A microscope might work, but ones that have calibrated distance
measuring on the eyepiece are expensive.

Perhaps a milliohm meter might be able to measure the difference in
resistance of a foot of it or so, but that's hardly a standard item
either.

Any suggestions?

I use either a dial calipers or a micrometer. But then the insulation
can make it sizeably larger than the value given in the wire tables.
The wire tables have a column which gives 'ohms per 1000 ft' which is
just another way of saying milliohms per foot. So if you measure ten
feet of 30 AWG it should measure 1.04 ohms. My cheap meter test leads
are something like .4 ohms, so it's really difficult to get any accuracy
at that low a resistance. I have a Leeds Northrup wheatstone bridge,
and it's not very good either at that low a resistance. So I put the
wire or whatever on a power supply and crank up the current to a quarter
amp, and then measure the V drop and calculate the resistance from that.


Thanks,

A

"Ian Stirling" wrote in message
...
In sci.electronics.design Albert wrote:
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire
and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

Micrometer.
Vernier caliper may also work.
Either under $30US.

I don't believe anyone uses vernier calipers anymore. I've got a Helios
dial caliper made a long time ago in Deutschland, but nowadays a caliper
with a LCD is probably a lot cheaper.

"Dave Platt" wrote in message
...
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire
and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

A cautionary note - if it's that critical, then re-using wire which
has alread been wound might not be the best idea. You'd be starting
with wire which had already been bent/flexed, and if you aren't
careful this might put some kinks or irregularities in the winding of
your new coil which might affect its impedance or Q.

I know I can weigh it, provided it's not on a spool or motor winding
already.

My local electrical shop has a wire gauge, but it stops at 18 gauge.

A microscope might work, but ones that have calibrated distance
measuring on the eyepiece are expensive.

You might be able to do it with a vernier caliper.

24 gauge has a diameter of .511 mm or .0020"

30 gauge has a diameter of .255 mm or .001"

Man, are you _way_ off! By an order of magnitude! Put your glass on
and reread the wire tables.

Every 3 gauge numbers corresponds to a 2:1 ratio in wire area (amount
of copper). Every 6 gauge numbers corresponds to a 2:1 ratio in wire
diameter.

--
Dave Platt
AE6EO
Hosting the Jade Warrior home page:
http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

On Sat, 9 Apr 2005 04:36:20 -0700, "Watson A.Name - \"Watt Sun, the Dark
Remover\"" wrote:


"Ian Stirling" wrote in message
...
In sci.electronics.design Albert wrote:
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire
and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

Micrometer.
Vernier caliper may also work.
Either under $30US.

I don't believe anyone uses vernier calipers anymore. I've got a Helios
dial caliper made a long time ago in Deutschland, but nowadays a caliper
with a LCD is probably a lot cheaper.


I do, got fed up with resetting the mechanical dial type through the rack and
pinion becoming dirty, and electronics/robustness issues with electronic types.

Peter

I read in sci.electronics.design that "Watson A.Name - \"Watt Sun, the
Dark Remover\"" wrote (in
) about 'wire size question', on
Sat, 9 Apr 2005:

I don't believe anyone uses vernier calipers anymore. I've got a
Helios dial caliper made a long time ago in Deutschland, but nowadays a
caliper with a LCD is probably a lot cheaper.

In UK, you can get vernier calipers for around GBP1 (and mine check out
as quite sufficiently accurate). LCD calipers are about GBP35.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk

wrote in message
oups.com...
From: "Henry Kolesnik" on Thurs,Apr 7 2005 10:15 pm

Get a nice piece of smooth round rod and tightly wind a little over a
lineal
inch of wire closely spaced as possible. Count the turns in one inch
and
divide the number of turns into one inch and you'll have a very good
measurement without any cost.

73
Hank WD5JFR

Albert wrote in message
...
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire
and
some #30 for a coil, but have to be sure regarding the wire
diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

I know I can weigh it, provided it's not on a spool or motor
winding
already.

My local electrical shop has a wire gauge, but it stops at 18
gauge.

A microscope might work, but ones that have calibrated distance
measuring on the eyepiece are expensive.

Perhaps a milliohm meter might be able to measure the difference in
resistance of a foot of it or so, but that's hardly a standard item
either.

Any suggestions?

A non-destructive measurement is best. Along about
1946 my middle school (we called it "junior high" back
then) electric shop instructor demonstrated how to use
a mechanical caliper and how NOT to squeeze too hard in
doing so. Soft-drawn copper common to wire is fairly
easy to squash when using a caliper. Using one requires
a VERY light touch on the wire, just enough to be able
to pull it slightly through the caliper jaws. Even so,
pulling on soft-drawn copper wire is going to distort it
slightly so the measurement is going to be on the small
side. Snipping off ten or twenty short lengths, then
measuring the total width and dividing by the number of
lengths will be a bit better in accuracy.

HUH? What do you mean, Jellybean?

[snip]
Just some practical thoughts after doing a bit of
winding in my time...

Uh, yeah...

"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:

Albert wrote in message
...
Does anyone know how to measure or determine the wire size. I have
tons of motors, solenoids, and similar items. I need some #24 wire and
some #30 for a coil, but have to be sure regarding the wire diameter
as it's a critical ap and the author of the article says 'don't
substitute'.

I know I can weigh it, provided it's not on a spool or motor winding
already.

My local electrical shop has a wire gauge, but it stops at 18 gauge.

A microscope might work, but ones that have calibrated distance
measuring on the eyepiece are expensive.

Perhaps a milliohm meter might be able to measure the difference in
resistance of a foot of it or so, but that's hardly a standard item
either.

Any suggestions?

I use either a dial calipers or a micrometer. But then the insulation
can make it sizeably larger than the value given in the wire tables.
The wire tables have a column which gives 'ohms per 1000 ft' which is
just another way of saying milliohms per foot. So if you measure ten
feet of 30 AWG it should measure 1.04 ohms. My cheap meter test leads
are something like .4 ohms, so it's really difficult to get any accuracy
at that low a resistance. I have a Leeds Northrup wheatstone bridge,
and it's not very good either at that low a resistance. So I put the
wire or whatever on a power supply and crank up the current to a quarter
amp, and then measure the V drop and calculate the resistance from that.

I use that trick too. The only sensible way to measure a coil's winding R.

Graham