SET UP.
A
G
MATERIALS
The pendulum itself may be
fabricated from any number
of common materials including plastic, aluminum, and
wood; I used polycarbonate
plastic.
The exact size of the pendu-
lum may vary according to
the wishes of the maker.
I ordered my materials
from McMaster-Carr
(
mcmaster.com) because
they were easily available
and not too expensive; you
can also get parts from
a local supplier, a surplus
dealer, or another mail order
supply firm.
Photography by Ed Troxell
[A] 8mm steel rod,
3" length for the main pivot
on which the pendulums
rotate.
7" wood dowel is an
acceptable substitute,
although you’ll need to
slightly build it out
with tape or foil so it
fits the bearing snugly.
B
C
F
[B] Skateboard bearings
( 7) High-quality bearings
that reduce friction to an
absolute minimum are
the key to getting the best
performance from your
pendulum.
Skateboard bearings are
relatively inexpensive high-
performance bearings, sold
in skateboard stores
in quantities of 8, generally
packaged in small metal
cans resembling mint tins.
The quality of the bearing
is determined by its ABEC
designation: ABEC- 3 bearings are good, ABEC- 5 are
better, and ABEC- 7 or “Swiss”
bearings are great. Buy the
best you can afford.
[C]
7" bolts, 1" long,
with nuts ( 2) for attaching
pendulum bearings
[D] Sheet of polycarbonate
plastic 12"× 12"×¼" thick
E
[E] 3V coin cell battery
(optional) to power the LED
[F] LED (optional) for
time-lapse photography of
pendulum in action
[G] Rubber washers,
1" ID ( 2)
[NOT SHOWN]
Nylon washers or
plastic spacers
8mm shaft collar
(optional)
D
TOOLS
Jigsaw, band saw,
or table saw
Rotary tool or file
Rubber mallet
Epoxy glue
Sandpaper
Measuring tape
Electric drill with 22mm or
q" spade drill bits
Hacksaw if you’re using
steel rod
95 Make:
