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Making a Wheel for a Robot
Here are some quick hints on how to make a plexiglas wheel. Obviously, this
method uses a lathe but I've heard of people making something suitable with just a
drill, sandpaper, saw, and some patience. However, if you don't have the right tools,
a much better way would be to
take a community college metals course and, in the process of using their equipment and learning a really
kewl skill (with expert guidance around to stop you from chopping off your typing fingers),
you can run off a half dozen wheels or so for your robot hobby!
the above wheel is about 5", but you can make much smaller wheels using this technique. The O ring is
a Eureka vacuum cleaner belt and it is readily available in most stores. There are
two versions that I'm aware of, one is about 3 1/4" and the other is about 4 1/4". When
stretched, they make good 4" and 5" tires. You can get smaller O rings from the hardware stores that were
meant for faucet and sink repair.
If you want to work with the plexiglas you need to be able to hold it in either the
drill chuck or the lathe. Above is a jig I made from a piece of brass. It has a
3/8" hole through it with a 1/2" collar. Note the index mark on the side so I
can put it into the lathe chuck in exactly the same place each time.
I drill a 1/2" hole in the center of some
rough cut plexiglas (you can use liquid detergent as a lubricant for the plexiglass - works
great when you cut it with a scroll saw!) and then put the plex on the jig as seen above (the
protective plastic is still on the plexiglas, so it looks kindy milky).
Chuck the whole thing up in the lathe, turn it to size (note the protective wrap is off so the
plexiglass looks nice and clear here), and then ..
Cut a groove in the edge of the plexiglas so the O ring tire will hold tightly.
The tires for these wheels (about 5") are Eureka vacuum cleaner belts. You might
want to 'super' glue the tires to the rim since side forces can sometimes knock
even the tightest tires off.
Next, make a hub, which is very similar to making the jig. Just turn some brass in
a lathe, drill a hole in the center the size of your motor shaft, turn a
1/2" collar, slice it off about 1/8" on the back and mount it through the wheel. In this case, I put set screws in the
hub to fasten it to the 1/4" motor shaft.
Sometimes, stretching the O ring over a wheel can be very difficult. I've found it
easier to put a few nails in a board, put the O ring around the nails, lay the wheel inside
the O ring and then lift the O ring out one side at a time.
Here is the final product, the wheel has been painted because I really don't like clear plex. As you can see, the effect
is pretty good and it is reasonably easy to do.