Why does your wind up watch lose time?

Answer 1

There are numerous reasons why a wind up watch may lose time - some are obvious and others are tricky and not immediately evident. Among the reasons in the first category: lubrication has broken down and friction has increased: old lubrication has attracted debris and friction has increased further: tips of pivots have developed grooves and are further increasing friction, a part somewhere has become bent and is creating unplanned drag; the spring providing motive force has become "set" or lost its ability to expand, so power directed to the wheels has decreased. Unless a part somewhere has suffered physical damage, most of the problems described previously can be cured by cleaning the watch plates and gears that run between them, of the old lubrication and dirt, and then applying fresh lubrication to a clean mechanism. If the pivots, or tips of the wheels have become scored, they need to be polished smooth or replaced. If the holes in which the pivots revolve have become deformed, or a jewel bearing cracked, they need to be fixed or replaced. A possible cause that may not be immediately evident is that the canon pinion has loosened and is slipping. In other words, the hands are carried by a gear that has only been pressure fitted to a pivot, located in the center of the dial. If the "press fit" is loose, and this is typically determined while setting the hands and "feeling" some resistance, the mechanism may be running just fine but the hands may be slipping, causing the watch to appear to be lose time when it is in fact running perfectly. This fault is corrected by removing the canon pinion and slightly deforming one edge so that it fits tighter on the central wheel. Yunus Kenter, avid watch enthusiast.