Building an Inverted Pendulum System The Ups and Downs of Defying Gravity…

I tried a bunch of different screws and found out that the set screw is a 6-32 screw.  This is the same size screw thread that is used to hold the wall plate around light switches.  First I tried using a light switch screw, but the head was much too large since the set screw hole is pretty close to the side of the gear.  I wasn’t able to find anything else useful in my collection of screws and bolts, so I went to the hardware store.  I was looking for a fairly short screw with a small head.  I found a couple that looked good that had small round heads.  One uses a regular flat blade screwdriver, and the other has a phillips head.  I tried the phillips head screw first because it was shorter and easier to turn, but the head was still too large.  It rubbed against the gear as I turned it.  Next I tried the other screw, and it worked pretty well.  It doesn’t rub on the gear at all.  It was almost too long, though.  After I tightened the screw, which was very easy and nothing stripped, I put the cart back on the rack.  As the gear rotates, the screw barely clears the rack.  I think this screw will do the job, but I am going to look for a shorter screw with a small head just for appearances.