Step 3: Attaching one wheel to the geared motor

One wheel is driven by the geared motor. On a windscreen wiper motor the connection to whatever is driven is usually made pressing it on the axle with the bolt. But with plastic plates/wheels that does not work well. Instead, with the bolt screwed on completely I drilled a 2,5 mm hole through bolt and axle, in order to be able to insert a nail. Nail and bolt are removed and before the wheel is put on one or two washers are added to make the wheel fit tightly but not being squeezed under the bolt screwed to the end. Some small screws in the wheel catch on to the nail put through the hole again. Some hot melt glue put on top removes any slack and prevents the nail of falling out.