Dancing Skeletons 2

page 2

Motor Mount

We'll use the 4x4 post cap as the bracket for mounting the motor.
Start by cutting two pieces of the 1" angle aluminum, 20" long. (For planning purposes, we'll need the two 20" pieces and also two 12" pieces)
Temporally place them on either side of the post cap as shown at left.

Remove the rotating arm that comes with the motor. We won't be needing this. Be sure to save the nut and washer.
Temporarily place the motor on the bracket as shown right. The motor shaft goes through the large hole in the center of the post cap.
Rotate the motor so that it fits between the two pieces of angle aluminum.
With the shaft of the motor centered in the hole in the post cap, using a marker, trace around the three mounting posts of the motor so as to leave markings on the post cap showing where to drill holes to mount the motor.

Using a 1/4" drill bit, drill through the centers of the markings from the previous step.
If you marked and drilled everything perfectly, the motor mounting holes should line up with the holes in the bracket. Adjust as necessary.
Using the 6mm screws and three of the 1/4" lock washers, mount the motor to the bracket. It should look like the picture to the left.

In this step, we'll modify the two 20" pieces of angle aluminum so that they'll fit around the motor mount screws.
Make a mark on each piece of the angle aluminum 3" in from the end.
Set the two angle aluminum pieces over the motor bracket with the 3" marking even with the edge of the motor mount, as shown right.
Mark each piece of the angle aluminum where the motor mount screws interfere.
Using the appropriate tools, trim away the aluminum to fit around the motor mount screws (I used a nibbler tool and a round file. You could also just file away the aluminum or notch it with a hacksaw). Be careful not to cut too much material away.

Next, we'll mount the motor mount to the two 20" pieces of angle aluminum.
Holding one piece of the angle aluminum in place, with the 3" mark lined up on the edge of the motor mount, drill a hole for a #10 screw about 1/4" in from the edge of the motor mount and halfway down the angle aluminum.
Place a #10-32 x 1/2" screw through the hole and fasten with a lock washer and nut.
Repeat for a second hole as shown in the picture on the left.
Now do the same thing for the angle aluminum on the other side.

In this step, we'll attach two cross pieces of angle aluminum. These will be used to mount the motor mechanism to the wooden frame.
Cut two pieces of angle aluminum, 12" long.
Center one piece of the aluminum on the motor mechanism angle aluminum as shown at right.
Drill two holes for #10 screws and attach the cross piece to the motor mount using two more of the #10, 1/2" screws, lock washers and nuts.
Repeat the same procedure for the other end of the motor mount angle aluminum pieces.
Note in the picture at right, I have also drilled four holes in the cross piece of angle aluminum for later mounting to the 2x2 wood. This would be a good time to drill those holes in both cross pieces.

Now, we'll make the arm that goes on the motor shaft.
If you haven't done so already, cut a 12" long piece of the 3/4" flat aluminum stock.
On one end, drill a 1/4" hole, centered on the stock, about 5/8" in.
On the other end, drill a 5/16" hole, again, centered on the stock and 5/8" in.

We need an offset bend to keep the rotating arm clear of motor mounting hardware.
On the end of the arm that has the 5/16" hole, mark a line across the arm at 1" and another at 1 1/4" in from the end.
Clamp the arm in a vise at the 1 1/4 "mark, with the short part of the arm exposed.
Using a hammer, bend the short piece of aluminum arm to about a 45 degree angle. Use multiple, somewhat gentle blows with the hammer instead of pounding real hard.
Now, flip the piece over in the vise and align the 1" mark with the top of the vise. The long piece of the arm is now exposed above the vise.
Bend the arm in the opposite direction until the short section with the hole is parallel to the longer section. The bend should look something like the picture on the right.

Here, we'll prepare a fender washer to which the lines controlling the skeletons will be attached.
Drill three small holes, evenly spaced, about 1/8" from the edge of the washer as shown to the left. You'll need nice clean holes to avoid cutting the fishing line which will be attached later.
Put the washer on the 1/4" x 1" screw and add two 1/4" nuts as shown at right.
Leave about 1/16" space between the washer and the top nut to allow the washer to spin freely. Tighten the nuts against each other to lock them in place.

Mount the washer mechanism to the end of the arm with the 1/4" hole using a 1/4" lock washer and 1/4" nut.

Mount the arm onto the motor shaft as shown right.
You'll want to tighten the shaft nut fairly tight so that the hole in the arm is slightly forced onto the tapered part of the motor shaft. This should keep the arm from slipping when the motor rotates.
This completes the mounting of the motor :-)

last update 12/2016