won the fight by forcing BDRW into
the pit arena hazard. The arena
used was SECR-FL’s fully enclosed
stage made of bullet proof and
highly durable Lexan plastic, with an
80/20 aluminum frame. It is
designed to protect drivers and
spectators from the hazardous
shards of metal, along with
occasional detached saw blades.
Beetleweight Plagarist demonstrated
this by burying its saw blade into
the arena wall so solidly the fight
had to be stopped to extricate it
and check the arena for soundness.
As for the Beetleweights, the
ShazBot takes on Little Scoop in a lifter vs.
thwack antweight battle.
event was held round robin, with
every robot competing against
another until all bots have fought.
Wallop, of Team Nightmare and
driven by Jim Smentowski, placed
first. The other places were
somewhat difficult to determine,
but John Henry of Legendary
Robotics may have placed second.
As for third, Plagarist, Pacman, or
Push it to the Limit (Team Bot Works,
G3 Robotics, A.G. Robotics) may
have earned that title. Pacman
actually beat JH, so results are iffy.
In the end, it may have been
difficult to determine who won, but
a few things are for sure: Robots
were destroyed and everybody had
a lot of fun. SV
PARTS IS PARTS
Wheels f r Drills
Iwrote an article for the November ‘06 issue of SERVO that outlined
how to convert the motors and
gearboxes from cheap cordless drills
for use as the drivetrain in smaller
combat robots. In that article, I
recommended using wheels and
hubs from a company called CNC
Bot Parts. That source has since
dried up and as I needed more hubs
for my 12 lb spinner Surgical Strike,
I decided to make my own.
A typical cordless drillmotor and
matching Colson wheel can be seen
in Figure 1. The Colson wheels are
very popular in the smaller bot
classes because they are cheap and
tough. The most popular sizes are
the 3” x 7/8” or 4” x 7/8” and you
can buy them from
www.robot
marketplace.com.
The original hubs had worked
pretty well but they had a couple of
flaws that I wanted to remedy with
my new design. The first problem is
that they were a simple press fit to
the wheels. When first pressed in,
they are a very tight fit but the
plastic center of the wheel slowly
loses its grip over time so that after
● by Peter Smith
a couple of years, the wheels will
start to move relative to the hubs.
This can result in a couple of
problems. Firstly, the wheel can start
to slide back off the hub and even
fall off completely. This is not good
in the middle of a fight!
The second problem comes
when you try to remove the
wheel/hub from the gearmotor and
the wheel just slips on the hub
rather than unscrewing from the
axle. (I’ll cover each feature of the
design as I go through the process
of making them.) I used my 1970’s
12 x 36 Clausing lathe but any small
lathe would suffice.
Be sure to wear safety glasses,
remove loose clothing and jewelry,
FIGURE 1
and follow all the manufacturers’ safety
instructions before using a lathe.
They are not toys and can cause serious
injury or death is used incorrectly.
I made the main hubs from 1”
6061 aluminum hex bar. It’s cheap,
light, and machines easily. I chose
hex bar as it means that the rear
flange of the hub will be a perfect
fit for a 1” wrench. This comes in
very handy if the hub seizes on the
axle. Put a wrench on the hex and
give it a sharp rap with a hammer
and it will almost always break free.
The rear hex flange stops the wheel
sliding inward on the hub.
Figure 2 shows the initial
machining of the bar down to the
correct diameter and length. In Figures
FIGURE 2
SERVO 09.2009 31
