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Ligne for watches

fuzz1

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Mar 30, 2022
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Hi
I am a bit puzzled by the ligne measurement for watches.

Saw the conversion of ligne to mm as 1 ligne equivalent to 2.256 mm

But saw a movement advertised as 25.6 mm ligne 11.5.

That makes it not really 11.5
So just wondering if it's really 2,256 mm the ligne
Thank you
 

gmorse

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Hi fuzz1,

The conversion factor you mention is correct, it is 2.256, see here for more information. 25.6 mm is 11.34 lignes, so not too far out!

Regards,

Graham
 
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fuzz1

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Thank you my friend.

I been browsing the website of cousinsuk and found that the conversion doesn't match.
e.g ETA 956.112 is advertised as 17.2 mm 7.75 ligne
I checked several but the conversion of 2.256 for 1 ligne doesn't come true
 

gmorse

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Hi fuzz1,

I think you'll find that they're probably rounding to the nearest quarter of a ligne, (0.564mm), which is quite good enough for most purposes.

Regards,

Graham
 
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fuzz1

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Hi
Thank you Graham. I did not realise that it would be insignificant the difference. In watches thought everything needed to be as precise as possible. Close to the real value
 

Tom McIntyre

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Hi
Thank you Graham. I did not realise that it would be insignificant the difference. In watches thought everything needed to be as precise as possible. Close to the real value
Precision is only really required in the mechanism. Size of movement and case are style elements and require a lower precision allowance because of the multiple sourcing.

This is an industry issue, not a design issue.
 
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