PROJECTS: SOLAR TRACKER
1n. When the polyurethane is dry, run the t" drill bit through
the protractor image’s origin point, so the t" brass tube can be
mounted in this hole when needed.
2. INSTALL THE MOTOR
2a. Cut ¾" lengths of both the ¼" aluminum and the t" brass tubing, to make 2 cylindrical shims.
Clamp the aluminum shim in a vise and enlarge its inner diameter by drilling with a #21 bit. Check that the
2 shims nest together and will slip over the motor shaft and fit into the bronze bearing.
2b. File a
1"-wide flat on one side of the bronze bearing, then
center-punch marks on that flat, ¼" in from each end. Use a #21
bit to drill through the bearing at each mark, then use a #10-32
tap and handle to thread each hole for the setscrews.
2c. Slip the bearing over the drive wheel’s axle, install 2 of the
setscrews at the wheel end of the bearing, and make sure the
wheel turns freely. Slip the nested shims over the motor’s drive
shaft, then slip the shims and drive shaft into the other end of
the bearing. Make a mark through one of the remaining setscrew
holes with a fine-tipped marker, then use the narrow edge of a file
to file slots through the shims that will permit the third setscrew
to reach the flat on the motor’s drive shaft.
WARNING: Never apply torque to the motor’s shaft;
you may strip its gears! !
2d. Use the #4-40 screw, nut, and washer to attach one mounting
flange of the motor to the 1"× 1"×½" corner brace. Fit together the
drive wheel, coupling, and motor shaft, keeping the motor’s flanges
as horizontal as possible and the corner brace flush against the
underside of the turntable. Mark and drill a #21 hole for the screw
to anchor the corner brace; it will be off to one side from the drive
coupling. Countersink the hole on the topside of the turntable and
install a ½" flathead screw with a nut underneath to anchor the
motor. Install the third setscrew to fix the bearing to the drive shaft.
2e. With the turntable still inverted, lay the base disk on the wheels and check whether the motor’s
unused mounting flange sticks up to touch the base disk. If so, file it down to open up some clearance.
106 Make: Volume