off enough insulation to allow the correct number of
turns to be wound around the pin. Then, either place the
end of the wire in a long shallow groove along the barrel
of the wire-wrap tool or insert it into the smaller hole at
the end of the barrel, as shown in view A of figure 5-17.
The groove (or hole) for the wire is carefully sized to
provide the exact amount of tension you will need to
form a secure wrap. Make certain the insulation bottoms
into the wire funnel, as shown in view B. This will allow
you to wrap the correct amount (one to one and a half
turns) of insulated wire around the wrap pin. Anchor the
wire by bending it into the notch in the sleeve, as shown
in view C. Next, slip the center hole at the end of the
barrel down over the pin, as shown in view D. Then
rotate the barrel around the pin. (Depending on the
design of the wire-wrap tool, the barrel will rotate as a
result of finger, hand, or motor action.) The wire should
twist around the pin, as shown in view E. As the wire
twists around the pin, the stripped portion of the wire
that is being held in the groove (or in the other base hole)
will be drawn down to twist and coil around the pin. The
coiling action of the wire on the pin lifts the tool enough
for you to continue the wire coil up the pin, as shown in
views F and G. Your skill is especially important at this
point because too much pressure on the tool will cause
the coils to bunch or overlap. If you are replacing a wire,
carefully run the wire to the next connection and
perform the same procedure on the opposite end. Be sure
you allow enough spare wire for the required number of
wraps on the pin.
Figure 5-18.--Correct and incorrect wire wraps.
Before actually doing a wire wrap on the item you
are repairing, take time to practice this procedure. Find
a spare connector or spare pin similar to those you will
spaces between adjacent turns. (See fig. 5-18, view B,
repair. Using the same materials required for the actual
sec. 1.)
job, practice a few times. Figure 5-18, view A, shows a
2. Overtension on the wire, resulting in a loose
good wire wrap. It has five to seven and a half snug turns
of wire. Place the insulation about the bottom one or two
connection. You can detect this fault by the turn overlaps
turns with no spacing between adjacent turns, no
and the fact there is not enough surface contact with the
bunching as one turn tries to cover another, and no
pin. (See sec. 3.)
observable nicks in the wire. The number of turns you
will use is based on the wire gauge. Wires and pins with
3. Insufficient number of turns (fewer than five),
larger diameters require fewer turns; those with smaller
resulting in poor contact. (Not enough wire was stripped
diameters require more turns.
first.) (See sec. 4.)
4. Insulation does not extend to the pin, resulting
Avoiding Errors
in increased chances of shorts or wire breaks. (Too much
The following list describes a variety of
wire was stripped.) (See sec. 7.)
I N C O R R E C T wire-wrapping techniques. Some of
5. Reuse of uncoiled wrap. (Each reuse increases
these faults are evident in the numbered sections in view
the likelihood of wire breaks.)
B of figure 5-18.
6 . Attempts to wrap by hand, resulting in
1. Not enough tension on the wire, resulting in a
insufficient and uneven tension and poor contact.
loose connection. You can detect this fault by the open
5-16
