Over time, the eyelet in the frog can become worn out and needs to be replaced. After several replacements the threads in the frog that the eyelet screws in to can become worn out as well. This Bausch violin bow has been well loved and well used over the years and needs a frog bushing.
Have you ever had the eyelet strip or have the button become difficult to turn on your bow? I freaked the first time I experienced this as a student, fearing that something might be catastrophically broken. Almost in tears, it came as comforting news that the screw and eyelet is designed to have a service life and meant to be replaced over time.