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wire size question

A

Albert

Jan 1, 1970
0
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?

Thanks,

A
 
I

Ian Stirling

Jan 1, 1970
0
In sci.electronics.design Albert said:
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.
 
D

Dave Platt

Jan 1, 1970
0
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"

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.
 
G

Gary S.

Jan 1, 1970
0
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?
Two quick options:

Many kinds of wire have information printed on the insulation.

There are many tables which give the diameter, so machinists verniers
or a mike would do.

Or you could collect a set of samples of known wires and compare. Note
that solid and stranded are a little bit different.

Recycling solid wire from other coils might leave kinks or weak areas
where it was bent before. Insulation integrity matters, too.
Happy trails,
Gary (net.yogi.bear)
 
H

Henry Kolesnik

Jan 1, 1970
0
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
 
A

Albert

Jan 1, 1970
0
Thanks to my friend who emailed me the answer.

Around 5 dollars on ebay, wire gauge measuring gauge 1 to gauge 36.

Had no idea they made them that small.

Thanks to (you know who you are) and to all who made suggestions.

A
 
P

Pooh Bear

Jan 1, 1970
0
Albert said:
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
 
S

Spehro Pefhany

Jan 1, 1970
0
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.


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"

Ooops, you're low by a factor of 10:1 in the inch calculations. Just
as well, since a caliper is hardly repeatable to 1 thou, let alone
measuring a diameter of that size with any accuracy.
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.


Best regards,
Spehro Pefhany
 
D

Dave Platt

Jan 1, 1970
0
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"

Ooops, you're low by a factor of 10:1 in the inch calculations. Just
as well, since a caliper is hardly repeatable to 1 thou, let alone
measuring a diameter of that size with any accuracy.[/QUOTE]

Yup, I added a zero in there. 24 gauge is 20 mils (.02"), 30 gauge is
half that.

Works out to 50 or 100 turns per inch, close-wound, and the suggestion
to use that method was probably the best and cheapest I've heard.
 
R

Reg Edwards

Jan 1, 1970
0
Which gauge are you using?

British Standard wire gauge (SWG) ?
American wire gauge (AWG) ?
Birmingham wire gauge (BWG) ?

They're all different.
 
B

Bill Janssen

Jan 1, 1970
0
Ian said:
Micrometer.
Vernier caliper may also work.
Either under $30US.
And don't forget to remove any insulation before measuring the wire.

Bill K7NOM
 
R

Ross Herbert

Jan 1, 1970
0
And don't forget to remove any insulation before measuring the wire.

Bill K7NOM

Correct Bill. However DO NOT scrape the insulation from the wire since
this can alter the physical diameter of the wire. It is best to dip a
portion of the wire in fast acting paint stripper and wipe the
softened insulation off with a rag.

Ross H
 
J

John Woodgate

Jan 1, 1970
0
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.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Reg Edwards
Which gauge are you using?

British Standard wire gauge (SWG) ? American wire gauge (AWG) ?
Birmingham wire gauge (BWG) ?

Malt vinegar gauge - brown and sharp. (;-)
 
I

Ian Stirling

Jan 1, 1970
0
Correct Bill. However DO NOT scrape the insulation from the wire since
this can alter the physical diameter of the wire. It is best to dip a
portion of the wire in fast acting paint stripper and wipe the
softened insulation off with a rag.

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

Ross Herbert

Jan 1, 1970
0
Blowtorch to heat to dull red heat, and then wipe insulation off.


Sure is another option if nothing else. However, methinks it would
take just as much time to get a blowtorch out and running as it does
to open a can of paint stripper. It only takes 30 secs to soften the
insulation, and believe me, the result from the blowtorch is nowhere
as neat as the paint stripper.
 
G

Genome

Jan 1, 1970
0
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
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Ian Stirling
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. (;-)
 
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 news:[email protected]...

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.

A pocket optical comparator is handy for this and other
uses, especially when trying to get a measurement on
something already mounted with epoxy, varnish, etc. as
in windings of electric motors. While the "100-foot
resistance test" is a practical idea with a roll of
wire, it is hard to do when the wire comes from a
motor or transformer giving its all to the project.

As a practical matter, the wire size in small (such as
HF range) coils won't matter much on either the
inductance or Q tolerance. For example, Dropping from
30 AWG to 32 AWG isn't going to be a disaster in
cylindrical ("solenoidal") or toroidal forms. The
change in inductance will be aligned-out on trimming
in the circuit itself. Q is going to change much more
depending on the material of the coil former and the
presence of nearby conductive objects such as shields.

If a Twenty is too much for a pound or so of new wire
stock, then nobody can afford a Q Meter or inductance
meter to do an accurate measurement. Get with some
friends/acquaintences and share the cost of new stock.

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

[email protected]
 
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