Siemens & Halske Thread

Siemens & Halske Thread was used in telephones approx. 1900 AD.
The flank angle ranges from 50° to 68°.

Thread No.
 
Major Diameter
mm
Tapping Drill Size
mm
Pitch
mm
Thread Angle
°
11 8.95 7.0 1.21 50
14 7.20 5.7 1.05 58
17 6.00 4.6 0.89 55
18 5.75 4.5 0.78 58
21 5.12 4.0 0.78 58
25 4.00 3.18 0.66 61
27 3.37 2.58 0.66 68
29 2.80 2.22 0.53 66
31 2.16 1.63 0.49 68
33 1.78 1.39 0.34 59
34 1.63 1.29 0.30 55
36 1.22 0.95 0.22 50