of the jaw attachment point and try to line up the servo
arm. Don’t worry if you are off a bit as the hole in the
skull through which the wire runs may be enlarged later.
Next, cut the slot for the wire that will attach the jaw to
the servo (Figure 16).
The wire I use is 0.039 diameter stainless steel I get
from McMaster-Carr. It is only sold in packs of 100/12
inch lengths, but I have found plenty of other uses for this
wire in other projects. These are longer than you will
need, but hold off cutting them for now. If you are adding
LEDs for the eyes, you may need to enlarge the eye
sockets to accommodate them.
The same 1/8” bit you have been using should be fine
for this, as well. You can simply use the plain LEDs or
insert them into a pair of eyeball blanks. I purchased a pair
of wired two-pin headers and soldered an LED to each
one (Figure 17).
The header attaches to the board and the LEDs are
pressed into a hole you drill in the eyes. I then apply some
hot glue to the eyeball to attach it to the skull. This is the
method I use for my characters as it is an inexpensive
upgrade that seriously improves the look.
Finally, you will drill a small hole in the jaw to accept
the wire that connects to the servo. Insert the wire in the
slot that was cut earlier. Next, attach the wire to the servo
horn which is placed in the 1:00 position on the servo. I
use a special J bend tool to bend the wire to shape, but
you can do the same thing with a couple of pairs of
needle nose pliers (Figure 18).
It is now time for a little disassembly work. Remove
the jaw springs from the skull. This is a simple process that
requires the removal of a couple of screws. Your jaw
should now pivot smoothly.
Tighten up the zip ties a bit so the jaw moves easily,
but is still pulled up to the skull. Place the wire next to the
jaw attachment hole and after adding a couple of extra
inches, mark your cut. I like to leave a small space
between the teeth when the jaw is in the closed position
to keep them from banging together when speaking.
After inserting the wire through the hole, carefully
bend the end to keep it from coming loose. Be careful
with crimping down on the jaw with your pliers because it
is easily damaged if you use too much force! Cut off any
excess wire for a clean connection (Figure 19).
One additional hole you may want to drill is directly
opposite the servo horn screw. This will give you access if
■ FIGURE 18. The right tool for the job.
■ FIGURE 20. Speaker installed, along with the rest of
■ FIGURE 19. That wire is not coming off the jaw!
46 September 2017