Lignes Watch Movements

What Are Lignes?

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Lignes Watch Movements

If you’ve been in the Caliber Corner Community for some time, you’ve seen the word lignes here and there. What does it all mean? What is a lig-nez?!

Lignes is the French word for lines (and pronounced the same way), a unit of measurement for watch movements. Although most watch movements will have the diameters listed in millimeter (mm), you may also see linges listed – especially when dealing with raw movements.

Here is a brief history from Wikipedia:

The ligne or line or Paris line, is a historic unit of length used in France and elsewhere prior to the adoption of the metric system in the late 18th century, and used in various sciences after that time. The loi du 19 frimaire an VIII (Law of 10 December 1799) states that one metre is equal to exactly 443.296 French lines.

Interestingly, in addition to watch movements, the lignes unit of measurement is also used by some button and ribbon manufactures. Here is an explanation about lignes from ETA:

Following a centuries-old tradition, watchmakers use lines rather than millimetres to describe the size of the movement’s diameter. This measurement is generally indicated as a triple apostrophe, so 16 1/2 lines is written as 16 1/2´´´, or 37.22 mm diameter. The line, or Parisian line, is an ancient watchmaking measurement that predates metrification and is a direct descendant of the French pied (foot) measurement used under the Ancien Régime. Each line is equivalent to 2.2558 mm, which is rounded up to 2.26 mm for ease of calculation. In the past the French foot used to correspond to 12 inches measuring 12 lines each.

American watchmakers also had their own measuring system for watch movements, more on that here.

How to Measure Lignes

There are calipers and rulers that are set up for measuring lignes such as this one. If you don’t have a tool, you can convert mm to lignes the old fashioned way:

1 Ligne = 2.25583mm

And conversely 1 mm = 0.4433 ligne.

Representing Lignes

Caliber Corner posts as much information about each movement as possible – including the diameter in lignes and millimeters. When you see three ”’ after the number, it’s not a typo. That’s the linges measurement.

Lignes to mm to Inch Conversion Chart

Lignes Millimeters Inches
¼ 0.05640 0.0222
½ 1.128 0.0444
¾ 1.692 0.0666
1 2.255 0.0888
2.820 0.1111
3.338 0.1332
3.949 0.1554
2 4.517 0.1776
5.076 0.1998
5.640 0.2220
6.204 0.2442
3 6.768 0.2664
7.332 0.2886
7.895 0.3108
8.459 0.3330
4 9.023 0.3553
9.587 0.3775
10.151 0.3997
10.715 0.4219
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5 11.279 0.4441
11.843 0.4663
12.407 0.4885
12.971 0.5107
6 13.535 0.5329
14.099 0.5551
14.663 0.5773
15.227 0.5995
7 15.791 0.6217
16.355 0.6439
16.919 0.6661
17.483 0.6883
8 18.047 0.7105
18.611 0.7327
19.175 0.7549
19.739 0.7771
9 20.303 0.7993
20.867 0.8215
21.430 0.8437
21.994 0.8659
10 22.558 0.8881
10¼ 23.122 0.9103
10½ 23.686 0.9325
10¾ 24.250 0.9547
11 24.814 0.9770
11¼ 25.387 0.9992
11½ 25.942 1.0214
11¾ 26.506 1.0436
12 27.070 1.0658
12½ 28.198 1.1102
12¾ 28.762 1.1324
13 29.326 1.1546
13½ 30.453 1.1990
14 31.581 1.2434
14¼ 32.046 1.2656
14¾ 33.273 1.3100
15 33.838 1.3322
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15½ 34.955 1.3766
15¾ 35.529 1.399
16 36.093 1.4210
16¼ 36.657 1.4432
16½ 37.221 1.4654
17 38.349 1.5098
17¼ 38.913 1.5320
17¾ 40.041 1.5764
18 40.605 1.5987
18½ 41.733 1.6431
18¾ 42.297 1.6653
19 42.861 1.6875
19¼ 43.425 1.7097
19½ 43.989 1.7319
20 45.117 1.7763
21 47.372 1.8651
22 49.628 1.954
23 51.884 2.0427
24 54.140 2.1315
25 56.396 2.2204
26 58.652 2.3092
27 60.907 2.3980
28 63.163 2.4868
29 65.419 2.5756
30 67.675 2.6644

Hopefully this guide helps you understand lignes more, if there is anything we missed or any questions, please leave them in the comments below!

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