Thury Thread

Clock screw thread.
This thread was developed by engineer and university professor Thury from Geneva before 1900.
The flank angle is 47.5°.

Thread No. Major Diameter
mm
Pitch
mm
Tapping Drill Size
mm
0 6.000 1.000 4.800
1 5.290 0.900 4.220
2 4.660 0.810 3.728
3 4.110 0.729 3.224
4 3.620 0.656 2.808
5 3.190 0.590 2.492
6 2.810 0.530 2.164
7 2.480 0.480 1.924
8 2.180 0.430 1.684
9 1.920 0.390 1.432
10 1.640 0.349 1.280
11 1.490 0.310 1.128
12 1.320 0.280 0.964
13 1.160 0.250 0.900
14 1.102 0.230 0.724
15 0.901 0.210 0.648
16 0.794 0.190 0.562
17 0.699 0.170 0.496
18 0.616 0.150 0.440
19 0.543 0.140 0.372
20 0.479 0.120 0.336
21 0.426 0.110 0.288
22 0.372 0.099 0.252
23 0.328 0.089 0.223
24 0.289 0.080 0.194
25 0.254 0.072 0.164