Quote:
Originally Posted by locutus49
Why do most watches, when viewed through the back, have these large plates that obscure the movements?
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My 2¢:
It is simpler to fabricate large plates that will maintain parallel rigidity if the watch is sharply jarred.
Quote:
Originally Posted by locutus49
Exceptions are Langes and PP 5170s, where you can see the gears etc.
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Those makers want a true work of art and spend a lot of time designing/fabricating skeletonized plates. But the movement’s parts would experience more damage from shocks that the large plate movements could withstand.
Quote:
Originally Posted by locutus49
When people talk about adjusted in 5 or 6 positions, what does that mean?
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This is more detailed and depends on what accuracy a maker wishes to offer.
The short answer is to make it run accurately.
Long answer follows...
When you wear a mechanical movement watch, accuracy is affected by your many different positions during the day.
The balance wheel regulates the gear train and if it sat still in a face up position only, then would need but one adjustment. The center of gravity at the balance wheel is never perfect so the watchmaker would adjust for that to keep the beat rate consistently on target.
When a watch is horizontally, the balance pivots on one tip in a jewel bearing and has no variations to speak of. But when the watch vertical at 90°, the balance wheel oscillates on both pivots with greater friction. So there are the extra positions to be adjusted.
Of course. In real life, the movement goes through all sorts of angles and g-forces that affect the BPH.
When a movement is adjusted correctly correctly, the amplitude of the balance wheel will be averaged for the best accuracy In those 6 positions to provide the best chance of COSC (or better) performance.
By measuring the amplitude in different positions, and by micro adjusting the balance wheel, he/she can check to see if the improvement is enough to meet standards.
Long explanation, I know.
It is impossible for a mechanical watch to be perfectly accurate but these extra adjustments yields the best chance for acceptable performance.
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