French Thread

Was used in France before introduction of the S.I. Thread. S.F. = System Français.
The flank angle is 60°.

Thread-
No.
Nominal
Diameter
mm
Pitch
mm
Tapping
Drill Size
mm
0 6.00 1.00 4.70
- 8.00 1.00 6.70
1 10.00 1.50 8.05
- 12.00 1.50 10.05
2 14.00 2.00 11.40
- 16.00 2.00 13.40
3 18.00 2.50 14.75
- 20.00 2.50 16.75
- 22.00 2.50 18.75
4 24.00 3.00 20.10
- 26.00 3.00 22.10
- 28.00 3.00 24.10
5 30.00 3.50 25.45
- 32.00 3.50 27.45
- 34.00 3.50 29.45
6 36.00 4.00 30.80
- 38.00 4.00 32.80
- 40.00 4.00 34.80
7 42.00 4.50 36.15
- 44.00 4.50 38.15
- 46.00 4.50 40.15
8 48.00 5.00 41.50
- 50.00 5.00 43.50
9 56.00 5.50 48.85
10 64.00 6.00 56.20
11 72.00 6.50 63.55
12 80.00 7.00 70.90
13 88.00 7.50 78.25
14 96.00 8.00 85.60
15 106.00 8.50 95.95
16 116.00 9.00 104.30
17 126.00 9.50 113.65
18 136.00 10.00 123.00
19 148.00 10.50 134.05