Another excellent walk through.
These devices have been around for 40 or more years and still work! More importantly they can be pulled apart and cleaned up with simple tools and no tiny parts.
Score Reels are relativley easy to source still as most pinball repairers have boxes of them out the back. If you are unsure of your skills they make an excellent project to get your confidence up. There are enough parts to keep you thinking while the mechanics are pretty simple.
Only thing I would add is NEVER rotate a score reel backwards as this bends stuff and ruins your whole day....
Keep the info coming
Michael