Page 227 - Making things move_ DIY mechanisms for inventors, hobbyists, and artists

Chapter 7 Bearings, Couplers, Gears, Screws, and Springs 205

FIGURE 7-17 A gearhead motor with a flatted shaft makes it easier to attach components
with set screw hubs (credit: ServoCity).

If the motor you need does not have a flat section to the shaft, you can always file in
a small patch with a metal file. Others have grooves (called keyways) cut out of the
motor shaft and mate with a component with a matching key cutout. Some motors
even come with a tapped hole in the shaft so you can screw components directly into
them. At the very least, you should take a file or sandpaper to a circular motor shaft
to give it some texture to better enable components to hold onto it.

Attaching Components to Motor Shafts
If you’re really lucky, you can find a motor that has
a wheel or other component that matches the FIGURE 7-18 Components with
set screw hubs, like this gear from
shape of your motor’s output shaft. For example,
ServoCity, are easy to attach to
Solarbotics sells a great little DC gearhead motor kit motors (credit: ServoCity).
(www.solarbotics.com/products/gmpw_deal/) that
includes a motor with a shaft that’s flatted on both
sides, a wheel with a matching profile, and a
mounting screw to keep the wheel in place.

If you’re not that lucky, make your life easier by
searching for components (gears, pulleys, sprockets,
and so on) that come with a hub. A hub slides onto
your motor shaft and is secured with a set screw or
clamp (see Figure 7-18). Some components come
with hubs but without a set screw or clamp to