This documents how I dealt with the problem of transferring circular to linear motion wih a sliderail.
Electra’s slide rail looks like this
Before the slide rail the linkage from the servo to the flipper was by a rod. This was problematic. The movie below shows that in order to keep connected between the wheel and the flipper, the rod has to continuously change its length. My rod didn’t. This meant that the flipper was buckling as it moved.
The slide rail allows varying distances between the servo and the flipper. It also stiffens the flipper, which is a good thing as its only made of 1mm polycarbonate.