2
Parallax, Inc.
•
Boe-Bot Tank Tread Kit (#28106)
03/2004
The servo horn will need four of the holes enlarged for the 4-40 screws. The holes need to be smaller
than the screw so that when the screws are inserted they will make their own threads. You can drill the
holes using a 3/32
”
drill bit or use an X-acto knife to enlarge the holes as shown in figures 1 and 2 If you
are using the knife be sure not to over enlarge the holes. By reaming with the knife a little from the top
and bottom, the hole will be more uniform in size.
3/32
”
(2.2 mm)
Figure 1: Modify Disk Horn with Drill or Knife
Modify the disk servo horn by drilling or reaming the middle holes larger. If using a knife ream from the
top and bottom but leave material for threads to be made.
Wire cutters work well for trimming off the servo horn ends.
3/32
”
(2.2 mm)
Figure 2: Modify Standard Servo Horn with Drill or Knife
Modify the standard servo horn by drilling or reaming the inner holes larger. If using a knife ream from
the top and bottom but leave material for threads to be made.
Using the ¼
”
screws attach the two large wheels (with teeth) to the servo horns as shown in Figure 3.
Figure 3: Mounting the Wheel to Servo Horn
Mounting the wheel with teeth to the servo horn with ¼
”
screws.