Enzo...I understand what you mean with impact being more pronounced in pendant up, down etc, vs. horizontal positions. That got me thinking that the larger the size watch and larger the balance wheel the more critical poising becomes. Wouldn't inertia come more into play with the larger diameter balance wheels? I wonder to what degree very small watches are affected vs. large watches. BTW I need to add a couple of timing washers to my 3/0 Elgin. Running just a tad fast dial up with regulator at slowest setting.

Roger

Roger,

if we consider the formula above

... P D^2
I= --------
... 4 g


The mean value of ( g )is 9.8 metres/seconds^2

We see that momentum of mass inertia is directly proportional to the peripheral weights and to the square of the diametre of the balance wheel.

( P ) and ( D ) will be expressed in grams and in millimetres so the ( I ) of the small and big balance wheel would have a very marginal difference as the dividend ( 4g ) keeps the same as a constant value (if you do not change latitude).

So a small balance wheel watch has a less ( I ) compared to a large one but at the end due to proportions of watch components the behavior of the two watches in timing performances will be the similar even if dimensions are much different.

But both they will suffer for incorrect poising same way if any.

I hope I have been clear....

rgds

Enzo

Enzo...Thank You for the explanation...I understand completely.

Roger