Page 300 - Robot Builder's Bonanza

MOUNTING DC MOTORS 269

Figure 24- 4 Pipe holders or straps (in metal or plastic)
may be used to mount motors with round casings. Plastic
straps provide more leeway in matching the size of the
motor.

5. Use a hammer and a block of wood to fold over the exposed leg of the bracket. You
want a neat 90° angle.

G When making small brackets, drill the holes first, then cut the strip to length. You can make
several bracket pieces at a time this way. If you need to make lots of brackets, draw the layout
on a piece of paper and use it as a template for placing the holes and cuts.

Bracket Blocks from Wood and Plastic
You can make convenient block- style mounting brackets out of small pieces of 1/2″ or thicker
wood or plastic. Start with a minimum 1.5″-long block. On one face of the block drill two
holes close to the outside edges. On the other face drill at least one hole toward the center
part of the block. You can then use the block as a type of L bracket.
For larger motors, use bigger and longer blocks. You may need two and even three mount-
ing holes per face. Drill larger holes for bigger machine screws.
For plastic materials, visit your local neighborhood plastics retailer (check the Yellow Pages
for one near you). Most have a discard bin in the front showroom with odds and ends. Look
for small scraps of thick nylon, acetal resin (Delrin), and ABS plastic. The scrap is usually sold
by the pound; enough material for a half dozen blocks should cost only a few dollars.
USING CLAMPS
If the motor lacks mounting holes, you can use clamps to hold it in place. U- bolts, available at
the hardware store, are excellent solutions. Choose a U- bolt that is large enough to fit around
the motor.
A technique that works with smaller motors is to use hold- down straps designed for EMT
(electrical) conduit pipes. The straps, like the one in Figure 24- 4, are available in various sizes,
to hold down pipes of different diameters. These pipe straps are available at your local home
improvement and hardware stores, in both metal and plastic. The plastic ones are easier to
work with and lighter.

Mounting and Aligning Motors
with Aluminum Channel

The same (but somewhat larger) aluminum channel used to construct robot frames can be
used to mount and align DC motors. Find a channel that’s large enough inside for your motors
to drop in place. A snug fit is best. This technique not only allows you to use a motor that
otherwise lacks a convenient means of mounting, but guarantees that the two motors are
precisely aligned with one another.

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