"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