Pivots are the ends of the axles (called "arbors" in the clock world) that spin in small holes drilled in the clock plates as the clock runs. These, along with the holes themselves, can become worn. The pivots must have a mirror-like polished surface in order to minimize friction within the train of gears.
The pivot shown here is one of those textbook examples of extreme wear. My mentor, Bob Frishman of Bell-Time Clocks, explains:
"This usually is a result of folks continuing to oil, and not clean, an old clock. The new oil just frees up the abrasive dirt and let's it keep grinding away the steel."
Indeed, he is right. This particular example had a few other factors which caused this wear, and I hope to post about them soon. For now, let's just say that creative home repairs aren't usually a good idea. Also, please don't add oil to a dirty clock! You will be doing more harm than good.
A slightly worn pivot can be put into the watchmaker's lathe, then filed, stoned, and burnished back to a reflective surface. Not this one. I will have to "repivot" this one. This means I will have to carefully cut the remaining pivot off, then drill a hole into the arbor, and fit a new piece of pivot wire into the end. For more on the process, you can read books such as The Clock Repairer's Handbook by Laurie Penman, Practical Clock Repairing by Donald DeCarle, and Clock Repair Skills by Steven Conover.
The owner of this clock will never hear about all this, but they will be getting their money's worth. Though tricky and time consuming, this is the kind of repair that is covered in the price of the overhaul that I am performing.