System Française (SF)

Both of these thread series are obsolete, having been replaced by ISO metric series.

French Standard Thread
Major Diameter Pitch,
millimeters
3 0.5
4 0.75
5 0.75
6 1
7 1
8 1
9 1
10 1.5
12 1.5
14 2.0
16 2.0
18 2.5
20 2.5
22 2.5
24 3.0
26 3.0
28 3.0
30 3.5
32 3.5
34 3.5
36 4.0
38 4.0
40 4.0
42 4.5
44 4.5
46 4.5
48 5.0
50 5.0

The thread form differs from the SI form only in having rounded roots, however, for sizes less than 3 mm, the thread angle may be either 60° or 50°.

French Metric Thread
Major
diameter,
millimeters
Pitch,
millimeters
0.3 0.075
0.35 0.075
0.4 0.100
0.45 0.100
0.5 0.125
0.55 0.125
0.6 0.150
0.7 0.150
0.8 0.200
0.9 0.200
1 0.250
1.2 0.250
1.4 0.300
1.6 0.300
1.8 0.400
2 0.400
2.2 0.450
3 0.6
3.5 0.6
4 0.75
4.5 0.75
5 0.9
6 1.0
Sizes between 6 mm and 90 mm are the
 same as the SI sizes in this chart.
90 6
95 6
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