This is a very nice vintage Seiko Pogue 6139-6005 chronograph recently serviced for a ClockSavant customer. The Seiko 6139 has a “push” design to increment the day and date wherein force is put on the crown to increment the day and date. This pushing exerts pressure on the crown and on the internal mechanism which includes an internal “finger” under a reasonable amount of spring pressure. This is shown in the picture. This finger pushes-along the day of the week when the crown is pushed. The challenge with the design is that when the watch is dirty and has not been serviced for some time, the owners will push on the crown harder to get it to increment (to bypass the dirt and lack of lubrication) and this can cause parts to grind-away at each other and chip, wear, or bend. Two parts that can fail are the day of the week wheel itself and the finger that pushes the day wheel. These are shown in the picture with representative areas of wear. This is another excellent example of why a vintage Seiko that isn’t properly serviced can experience accelerated damage. As we know, Seiko’s were not Sunday-only go-to-church watches ;-). People wore them daily and put them through the day-to-day tasks of their lives. To bring them back to their former glory, they need careful attention. This watch needed new finger and day wheel. After servicing, it is running very well with unusually strong amplitude (degree of balance swing.) It also passed rain and splash water resistance testing.
