[Smobews]

Originally Posted by padi56

Gravity affects mechanical watches the most thats why they are tested in 5 different positions,and in those different positions there will be slight deviations in the timekeeping.Remember this the escapement of a mechanical watch in 24 hours pushes the gears 432,000 times and a day has 86,400 seconds. But on the wrist with owners wearing habits given the fact that the movement is constantly affected by the earth's gravity, metal expansion and contraction,mainspring power-reserve, temperature variations, subtle changes in lubrication and friction, shocks, and so on.The fact is that no mechanical watch made will keep 100% perfect time, very close yes but perfect no myself would not worry about those few seconds,the COSC spec is a AVERAGE of -4 to +6 over 24 hours.

Today regulation is a very very simple task for any good watchmaker,its accomplished by turning the Microstella adjustment screws and nuts on the balance wheel.The two smaller Microstella screws make adjustments of one second for each turn on the tool, and the larger Microstella, two seconds for one turn on the tool,but adjustment must be balanced with the opposite gold adjustment screw.

Microstella tool this is the older tool Rolex now has a more modern one but it does the same job and adjustment is done the same way.



Balance-wheel.

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Peter, do you know how precise the adjustments can be made with the tool? Can the watchmaker fine tune and make 0.1spd adjustments? If a full turn is as small as 1spd, I would imagine that at least 0.25 spd micro adjustments can be made with easily definable quarter turns.