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.
