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need info regarding movements

November 23 2006 at 9:59 AM
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plz adv what is the difference between "adjusted to four position" and "adjusted to five position"

i discovered it on a certain mille miglia model - one states the 'four' an the other states the 'five' - both pieces are of the same model.

thank you

 
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MTF
(Login MelvynTeillolFoo)
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Positions >>

November 23 2006, 7:50 PM 

In the old days, pocket watches lived in waistcoat pockets in vertical position, usually crown-up, when crowns were at 12 o'clock. In this position the forces of gravity had the maximum effect "dragging" the balance spring out-of-round shape during its contracting and expansion. Thus, watchmakers took care to adjust the components to give best timing consistency in vertical position.

The main 6 positions that a watch (and its timing organ) can be are:
Horizontal; Face Up
Horizontal; Face Down
Vertical; Crown Up
Vertical; Crown Down
Vertical; Crown Right (3 o'clock)
Vertical; Crown Left (9 o'clock)

Depending on the time, effort and money that a watchmaker wants to spend adjusting the timing mechanisms, convention is to choose 4 or 5 most common positions to adjust. This is because each adjustment optimised for one position may affect timing for another position. The "best" adjustment is a compromise between all 6 positions (and at 2 standardised temperatures).

Most people do not put their watches face down; that may scratch the older mineral watchglasses. If 90% of people wear their watches on the left wrist, the common positions of rest are Crown Down (when standing/walking) and Crown at 9 o'clock (hands on desk or steering wheel). Many people place watches face up at night.

Thus, for 4 positions, the watchmaker could skip the face down and crown up positions. Strictly speaking, since gravity on Earth works in a vertical plane, and we live in a 4 dimensional world, the Crown Left and Right are the same i.e. mirror-image as far as effect of gravity is concerned.

Regards,
MTF


    
This message has been edited by MelvynTeillolFoo on Nov 23, 2006 7:55 PM


 
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Anonymous
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so which is best?

November 29 2006, 10:34 AM 

dear MTF ,

thank you for your generous ample information, truly appreciate that, so does it means that adjust to 4 is better than adjust to 5? since they kinda put more concern to have it adjusted to 5.

How come of the same model of 8915 mille miglia (two pieces) - one piece states adjust to 4 and the other piece adjust to 5? could it be those two pieces were manufactured on different years?

ps: your previous info really clear things up for us newbies. thx.

 
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MTF
(Login MelvynTeillolFoo)
Admin

In the real world >>

November 29 2006, 7:42 PM 

where life happens, it probably makes no difference whether it is 4 or 5 positions adjusted.

On a case-by-case basis, either way could produce the "better" timing watch.
Since the adjustment limits are so wide (-4 to +6 sec/day), a watch could have wide variability in 5 positions and "pass" e.g. -4, +6, +4, +5, -1. That would give a maximum variation of 10 sec/day from -4 to +6 and average deviation of +2.

I would prefer a watch that has low variability in 4 positions e.g. +1, 0, 0, -1 to give a maximum variation of 2 sec/day and average of zero.

In general, lower maximum variability, lower average deviation and higher number of positions tested is better. As noted before, 4 positions covers enough directions for gravity to have effect on a balance spring i.e. crown left for a right hander is the same as crown right for a left hander .

The nit-picking people will talk about "Other" factors of position that affect timing viz varying frictional forces if the weight applied to pivots and other components are different, creeping lubrication etc, so 6 positions is best.....

Movements can be sold in bits (ebauche), semi-assembled, fully assembled, unadjusted and adjusted. That accounts for supplies of 4 or 5 position adjustment labels. In the real world, for what use that you may have planned, at that price point, it makes no real difference to performance.

Chopard do NOT just buy a movement and slap it into a case. Their chronographs are mainly ETA 2894-2 with Chopard finishing and Dubois Depraz chronograph module added. The GMT models have ETA 7754 as base with Chopard finishing.

The important thing is how the pushers feel and timing seconds-hand starts movement, when choosing individual chronographs. This varies from watch to watch of the same model.

Regards, MTF

 
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ei8htohms
(Login ei8htohms)
AP Discussion Group

a tiny bit of misinformation

December 1 2006, 7:21 PM 

Hi Melvin,

I wanted to point out that crown left and crown right are not at all the same, either in terms of being mirror opposites of each other or in terms of making a difference for right wristers vs. left wristers. The only wearers for whom crown right is particularly important are those folks who wear the watch on the inside of the wrist.

_john

 
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MTF
(Login MelvynTeillolFoo)
Admin

I think I know what you mean BUT >>

December 2 2006, 2:31 AM 

when I strapped two watches to a test monkey , OK I didn't really have a test monkey but I used a test dummy instead, here is what I found as I looked at the dummy:

The dummy's arms were straight forward like grasping a steering wheel Italian-style. I stood outside the car looking through a window (left-hand drive for US readers)

The Lange watch on the left wrist had its crown left and the Rolex watch on the right wrist had its crown right from my viewpoint. When I walked to the opposite window, the crown positions were switched but in reality, the dummy never moved - I'm sure he was still

Thus as far as vertical gravity forces were concerned, there was no difference between crown left and crown right for the watches....

Explain?

Regards, MTF


 
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ei8htohms
(Login ei8htohms)
AP Discussion Group

try it again

December 2 2006, 1:06 PM 

Hello Melvyn,

Put the watch on the test monkey's (er, dummy's) left wrist and observe the position of the watch with the arms extended to the front. Then switch to the right wrist and observe. You'll notice that crown left (6H) is the position the watch will be in in both instances. The only common position that puts the watch in the crown right (12H) position is hands folded behind the head, the position I always find myself at work, smiling cruelly as my minions busy themselves around me.

_john

 
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