Gremlins- the re-pivoted balance staff
What you are looking at in the top image is the top pivot of a vintage watch balance that was re-pivoted a long time ago by a watchmaker who worked with what he had— skills but no spare balance staff. Extensive magnification is crucial to optimal watch servicing. Watchmakers in countries with less wealth or free market access learned to repair watches with what they had. The correct balance staff was likely available in most parts of the world when the repair was made because it is still available today. Not being critical, though arguable that he should have instead remade the staff if he couldn’t get a replacement, he also modified the escapement adjustment to work with this repaired balance staff which was now not according to factory specifications. What you see in the bottom picture is how very small balance staffs are measured. The net of the repair was that the watch ran but struggled to get the amplitude you want from this watch. The solution path, to replace the balance staff with a correct one and readjust the pallet, roller table, balance cock (it was bent to adjust to height), was a long path of recovery.