Because crown is the most frequently used component, so the crown shedding phenomenon is a very common malfunction. There are two situations about the crown shedding phenomenon: one is only the crown off and another situation is the crown and the winding stem split off together. The former situation is often because of the corrosion, the button back or because the crown is broken off impacted by the external force.While the latter situation is more complex, but generally speaking its because the tailhook break away from the stem and cannot lock the flute of the stem tightly. And the failure reasons including the wear of the plate and tailhook of the cross rail, the losseness of the cross rail screws and the deformation and demage of the stem. The old watches crowns are fixed by the cross rail screws while present watch crowns are basicly fixed by the cross rail shaft, so many old watch crowms exfoliation are because of the looseness of the cross rail screws.
The crown stem can be rusted very easily. When the watch has served for a long time, the gasket will ageing and cause the poor sealing, then the crown position will be the first water inlet. The root part of the rusted stem will taper and the watch will be decreased in waterprof strength. There is a kind of special two-section crowm (common in MIDO watch), this kind stem hsa two sections which are elasticly fitted to eatch other, and when the stem is rusted, it will be pulled out easily.
If your watch crown is fallen out, you should keep the crown well and send the watch to the watch repair shop. And if the watch crown and the stem are all shed, don't try to put it back on your own and don't put it in and pull it out angain and angain, because it will make the clutch wheel off the clutch fork and make more wear. These will make the maintenance more complicated.
And when you pull out the crown and do the hand settings in you daily life, do be cautious and slight. The components are all very small and fragile. So, if you pull out the crown very strongly, any normal watch can be pulled out,especially these ultra-thin watch and the small watch. Everone should be ware of this problem.
