FIGURE 4. ‘God Hands’ from Crafthouse.
with newer and better tubing products.
The best hands and fingers that I ever made used
simple 5/8 to 3/4 inch OD 6061 aluminum tubing cut into
finger segments and screwed together at the joints. I tried
rivets at first but they were hard to keep equal in tightness,
and harder to install and remove. Each segment was
beveled at the joint to allow inward bending. I made a
single cut on the long piece of tubing with a cutting tool
with my lathe before I cut it into segments. That gave the
fingers a great, shiny look. The same can be done with
sandpaper and the tubing chucked in a drill press. I spent
days of hand-filing down each of the segments until my
hands were black with aluminum dust.
In the assembly process, I used pieces of a straightened
clock spring inside the finger segments to hold them
straight except when the cable was pulling on the finger
segments. I believe the cables that I used were pieces of a
bicycle brake cable and the ends of each had a small
FIGURE 6. Complete Melissa robot from Crafthouse.
78 SERVO 01.2011
FIGURE 5. Melissa hands by Crafthouse.
tension spring attached to allow each of the four fingers to
exhibit individual compliance when grasping an object. I
used two small surplus linear actuators: one for the four
fingers connected together and the other for the thumb. I
wish I still had some photos of these hands but I traded
them for some other robot parts back in the late ‘80s. The
first set of hands looked and felt more like human hands
within the prosthetic glove, but the second set were way
more cool and robotic like — somewhat like the hands I’ll
Buy Fingers and Hands
for Your Robot
If you don’t feel adept at crafting a set of hands for
your newly-minted humanoid creation, you might want to
consider buying a pair from Crafthouse. The original hands
seen in Figure 4 — also called ‘God Hands’ — are priced at
about $1,935 a pair. If you are inclined to pay your
mortgage and eat occasionally in these tough times, the
newer set seen in Figure 5 (called the ‘Melissa Hands’ Type-
FIGURE 7. Melissa
hand spare finger.