FIGURE 9. Finished
built around a bronze sleeve bearing
with a 5/16” diameter bore (to suit
the axle) and a 3/8” outer diameter.
I used McMaster part 6391K156.
The flangeless pulleys from SDP-SI usually come with a large hub
and a steel setscrew. Remove the
setscrew and then secure it in the
lathe chuck by gripping the hub
A 3/8” drill is used to drill out
the bore of the pulley to match the
bearing. The part can then be
turned around and the hub
removed (Figure 6).
Mark out and drill the two
mounting holes. These don’t have
to be too precisely located since the
bearing will control the position of
the pulley relative to the beater bar.
The flanges are machined from
1.75” UHMW round bar; they have
a 3/8 center bore and generous
chamfers to help keep the belt on.
The mounting holes in the flanges
are added by mounting one of them
at a time onto the bearing with the
pulley and then marking the centers
of the mounting holes using a
transfer punch and the pulley as a
guide (Figure 7).
Upcoming Events for August – September 2011
The Homebrew Robotics Club will present their TABLEBot Phase II
Challenge at Google (1400
Crittenden Lane) on August 31st.
Phase III will be held on October
26th. Go to www.hbrobotics.org
for more information.
House Of Robotic Destruction 2011 will be presented by the
Ohio Robot Club at the Classic RC
Raceways in Akron, OH on
September 17th. Go to
www.ohiorobotclub.com for more
30 SERVO 08.2011