Page 301 - Robot Builder's Bonanza

270 MOUNTING MOTORS AND WHEELS

Figure 24- 5 Motors in a differentially steered
robot may be secured and aligned by placing
them inside a strip of aluminum U- channel. The
inside dimensions of the channel must be large
enough to accommodate the girth of the motor.
Use plastic cable- ties to hold the motors in place.

Cut the channel to length and, as shown in Figure 24- 5, place the motors within the chan-
nel, end to end. If the motors protrude from the channel, you might be able to secure them in
place using nothing more than a cable tie— for demonstration purposes, the illustration shows
one tie, but you’ll probably need several to hold the motor in place. Cinch up the tie so that it
firmly holds the motor.

Mounting R/C Servos

The world is quite a different place when working with R/C servos. By their nature, servos
have mounting flanges; what’s more, servo sizes and mounting configurations are fairly
standardized, giving you the option of premade mounting solutions if you don’t want to “roll
your own.”
Whatever the method, servos should be securely mounted to the robot so the motors don’t
fall off while the thing is in motion. Over the years, I’ve found “hard mounting”—gluing,
screwing, or bolting— the servos onto the robot body to be the best overall solution. These
techniques greatly reduce the frustration level of hobby robotics.

An exception to hard mounting is when creating so- called rapid prototypes, robots that test
G design principles and aren’t necessarily meant to last long. For these, things like Velcro, sticky
tape, and tie- wraps are adequate for the job. Read more about this concept in Chapter 14,
“Rapid Prototyping Methods.”

ATTACHING SERVOS WITH SCREWS
Unless you have a good reason not to, the best way to mount R/C servo motors to your
robots is with screw fasteners. You have two kinds of screws to choose from:

• Self- tapping metal or wood screws don’t need a nut on the other end to hold things in
place. Drill a small pilot hole to start, then insert the screw. The threads of the screw dig
into the material and hold it into place.
• Machine screws and nuts are ideal if you need to disassemble your creation and rebuild it,
or use parts for something else.

Specialty Premade Servo Mounts
With the popularity of servos for robotics applications there’s no shortage of mounts for all
types and sizes of servos. These are available from online sources and are not likely to be
something you’ll find at a local store; see Appendix B, “Internet Parts Sources,” for a selected
list of robotics specialty outlets, many of which offer servo mounts.

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