I recently had a client inquire as to why the minute hand on his watch always seemed to trail the second hand by half a minute or so whenever he set the time. This can be a common problem, particularly on mechanical watches because they need to be set more often. Most people either don’t notice or don’t care, but some do. For who do, this post is for you.
The cause of this problem is due to a necessary amount of play between the teeth of the gears that drive the hands. The horizontal play allows the gear teeth both freedom to move and prevents them from binding. You can sense this play when you turn the crown gently back and forth. When you do so, you should be able to note a fraction of a turn when the minute hand does not move after a change in direction (clockwise to counter-clockwise and vice-versa). This play of the minute hand can equal as much as a 30 second sweep of the second hand – as my client noted. The key to eliminating the delay of the minute hand starting to move after the time has been set, is to ensure that there is no clockwise play in the gears when the crown is pressed back into the watch.
The means I use to ensure that the gears are fully engaged when I set a watch before returning it to a client, is to move the minute hand roughly 5 minutes before the desired time and then moving it clockwise to precisely the position that I wish it to be in when the watch starts
Be certain not to move the crown counterclockwise when pushing it back into the watch as this will disengage the gear for the minutes slightly again and cause the same error.