Page 156 - Robot Builder's Bonanza

MAKING THE BASE 125

Use this straps, as shown in Figure 12-5. The TinBot
existing hole
design uses one of the strap holes to get things
started; you need to drill two additional holes in
each strap.
Use a new or recently sharpened 9/64″ bit
to drill the holes. As covered in Chapter 11,
2-5/8" start each hole using a center punch or a sharp
nail to make a slight indentation in the metal.
Apply a small drop of cutting oil, then set your
drill motor to low. Allow the tool to do the work
for you. Don’t press down too hard, or you’ll
Drill
Drill second dull the bit.
2-1/8" strap, but in
Drill mirror image
ASSEMBLING THE PLATES
AND STRAPS
Assemble the metal plates and straps as shown
in Figure 12-6. Use 6-32 hardware, with wash-
Figure 12-5 New holes need to be drilled into the ers top and bottom. Finger- tighten only until all
nail straps to conform to the holes already in the TP35
and TP37 plates. For each strap you need to drill two six fasteners have been assembled. Then go
new holes. back and retighten everything.

MOUNTING THE SERVO MOTORS
Refer to Figure 12-7 for a layout diagram for
the servo mounts. You need two of these. They
may be constructed out of 1/4″ aircraft- grade
plywood or expanded PVC, or 1/8″ polycar-
bonate or acrylic plastic (plywood and PVC are
much easier to work with). The dotted lines
along the bottom of the mount indicate optional
“cut- throughs.” Cut through at the dotted lines
if you have trouble cutting out the inside pocket
for the servo. This creates a slightly weaker
mount, but they’re easier to make.
You may also purchase ready- made servo
plastic or metal mounts, though you may need
to drill new holes to match the hole pattern in
the nail plates. The hole spacings in the layout
Fasteners are designed to match the TP35 nail plate used
on the TinBot.
6-32 x 3/8"
machine screw The servo mounts are attached to the robot
Assembled
Washer base using metal corner angle brackets, as
Plate shown in Figure 12-8. Assemble using 4-40
Strap
Washer hardware. Be sure to tighten the screws se-
6-32 nut curely, or they’ll work loose over time. The
Figure 12-6 Use 6-32 fasteners to assemble the brackets should be about 3/4″ on each side of
plates to the straps. the angle.

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