In article ,
Spehro Pefhany wrote:
On Thu, 27 Jan 2005 01:21:46 GMT, the renowned "Martin Whybrow"
wrote:
"Karl Townsend" remove .NOT to reply wrote
in message anews.com...
I have a multi conductor cable with very small wires. I guess 22 or 24
gauge. ( Its an antique printer cable from when the wires were way bigger)
I'm trying to spread all the wires out to a small terminal strip and I'm
having a couple problems.
First, my wire stripper wants to pull out several strands of wire when
trying to pull off a short length of insulation. This is just the standard
multi electrical pliers type multi tool that strips up to #10 wire. Do I
need a better tool or a better method.
Second, I don't want a failure of the wire under the terminal strip screw.
I'm thinking of folding back 1/2 inch of bare wire to double it and then
solder tinning the end to make it durable. or, is there a better way?
Karl
Karl
The best way to strip thin wires is with a Stripmaster (made by Ideal) or
similar tool; it has blades notched for each wire size, the blades can be
changed for different wire sizes.
There was also the "Nickless" stripper, which used medium soft
plastic to strip wires down to (at least) 28 ga. They deform over time,
so get a wheel of replacement blades at the same time.
And there are strippers which use hot wire to melt through the
insulation from both sides. I think that down around 22 ga you start
getting too small for it to work well.
Ideally -- you strip the insulation only a short distance with a
tool, and then pull it off while twisting (clockwise for most wire, but
some has a CCW lay. This twist keeps the wires from fraying out, making
the crimping easier.
[ ... ]
AWG22/24 wire is nice hefty hookup wire by my standards, but if you
don't have the right size of terminal block etc. I suppose it could be
troublesome.
I agree that it is a common cable wire size. Ribbon cables for
IDC connectors tend to be 28 or 30 ga.
If it's the kind of terminal block with two screws and a link, and the
wires are big enough, you could crimp insulated lugs onto the wires
(onto the wire, and another crimp onto the insulation as a strain
relief) and then put those under the screws. This is okay for 12V at a
few mA or higher, but if the voltage or current are very low, you need
a good crimp that might require a more professional tool than the
hardware store kind. Don't try to use automotive type crimp terminals
designed for huge fat wires, get ahold of some electronic ones
(probably not at Radio Shack).
http://www.mouser.com/catalog/620/922.pdf
The red insulated crimp terminals are for 22-16 ga, and the
(relatively rare) small yellow insulated ones are for 26-24 ga, IIRC.
Large yellow is for 12-10 ga, and regular blue for 16-14 ga. Each uses
its own size of dies -- or separate crimper if you get the *good* cycle
controlled ones made by AMP. When new, these have a color on the ends
of the handles showing which size terminal should be used, but this
chips off over the years, other than inside the handles. Most of them
just have a handle color matching the terminal insulator, except for the
crimper for the blue, which has one handle blue, and one green.
Note that the colors repeat through several cycles -- all the
way up to 4-0 wire (blue). Past the 12-10 ga yellow comes red (8 ga),
blue (6 ga), yellow (4 ga) red (2 ga), blue (1-0), yellow (2-0), red
(3-0) and blue again at (4-0).
Those up through the yellow (12-10 ga) are purely mechanical.
red (8 ga) through red (2 ga) are interchangeable dies which fit in a
relatively small hydraulic crimp head, and blue (1-0) though blue (4-0)
are interchangeable dies which fit a larger hydraulic crimp head. The
smaller head is available in a hand-pumped self-contained unit. The
larger head is either electrically pumped with automatic shutoff, or
driven by a foot-operated pump. The smaller head is available detached
for the electrical operation too. I'm still looking for a set of dies
for the 4-0 size -- I have all of the rest.
The really good professional ratchet ('controlled cycle') crimp tools
are pretty pricey new, a couple hundred dollars up, plus die sets, but
they show up on ebay regularly for a fraction of that.
Agreed. The ones which crimp the insulation support at the same
time as the wire termination are called (by AMP) P.I.D.G (Pre Insulated
Diamond Grip), and the terminals are sold with the same designation.
Others are available, but with not as good an insulation grip.
For the standard Jones barrier strip, I would suggest that you
get forked terminals to fit around the screw shanks. The ring type are
more of a pain -- and you risk losing the screws. (As well, some of the
terminal strips have the ends of the screws peened over so they don't
come out easily.
Mouser does stock the small yellow terminals, if you really need
them, but you will have to watch eBay for a bit longer to find those.
All of the AMP P.I.D.G. crimpers have adjustments for how tight
the insulation crimp is, to adjust to differing thicknesses of
insulation.
Good Luck,
DoN.
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