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...

wrote:
(snip)
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.
(snip)

Really? Hmmmm ...

"Michael" wrote in message
...
wrote:
(snip)
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.
(snip)

Really? Hmmmm ...

Bumfuzzles me why you'd want to cut it up into a bunch of hard-to-handle
strands. Just wind it around a dowel as someone else suggested.

Albert wrote:

Does anyone know how to measure or determine the wire size.

If I need to check, I use a vernier caliper to determine the diameter of
the strands ( 2*r )and then calculate the total cross-sectional area as (
pi*r^2 ) * number of strands.

This gives a result in mm^2. Which is the standard measure in most of the
world.

To do the same you'll need a chart to convert from cross-sectional area to
AWG. Google will find you one.


Graham

I read in sci.electronics.design that Albert wrote (in
) about 'wire size
question', on Thu, 7 Apr 2005:

Does anyone know how to measure or determine the wire size.

Use a micrometer or a vernier slide gauge to measure the diameter.
Assuming that your wire is enamelled, 24 AWG is 0.022 inch (maybe +/-
0.002) diameter and 30 AWG is 0.011 inch diameter.
--
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

"Albert" bravely wrote to "All" (07 Apr 05 17:29:15)
--- on the heady topic of "wire size question"

Al From: Albert
Al Xref: aeinews sci.electronics.design:8716
Al sci.electronics.components:12978 rec.radio.amateur.homebrew:9183

Al Does anyone know how to measure or determine the wire size. I have
Al tons of motors, solenoids, and similar items. I need some #24 wire and
Al some #30 for a coil, but have to be sure regarding the wire diameter
Al as it's a critical ap and the author of the article says 'don't
Al substitute'.
[,,,]
Al Perhaps a milliohm meter might be able to measure the difference in
Al resistance of a foot of it or so, but that's hardly a standard item
Al either.

A practical answer: measure the resistance of a known length of wire.
You don't need a milli-ohmmeter to do this. Simply inject an accurate
current into a known length of wire, let's say for example 1 ampere.
Then use a dmm on the 200mv range to measure the voltage drop. This
gives a direct reading of milliohms x feet. Multiply this value up to
a range of 1,000 ft and look it up on a standard wire table and read
the gauge column. That's it! No fussing with diameters or micrometers,
microscopes or conductivity. One note of caution: if the wire glows,
the current is too large!

A*s*i*m*o*v

.... ... Clavicula .. Rectus abdominus .. Corpus sterni .. Piramidalis

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'.

Any suggestions?

Thanks,

A

Well.... ignoring other things..... perhaps you'd like to explain why it's
so critical or give a link to the article.

DNA

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

"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

"Pooh Bear" wrote in message
...
"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.

Long as it doesn't start glowing red. ;-)

Probably not such a good idea for measuring the series R of inductors.
Unless you run a Hi Power tape demagnetizer over it when you're done..

BTW, speaking of tapes.. I read that the company that made Irish and
Ampex tape has closed. Looks like everyone has been going to CD-Rs.

http://members4.boardhost.com/culturama/msg/3217.html

Graham