Sandvik Coromant Threading - Manual (Page 116)

116
 = arctan sin tan()

2
 
 
 = arctan
number of startsP
d
2



 = arctan
P
d
2

 
60° 8.5° 6°
55° 7.5° 5°
30° 4° 2.5°
29° 4° 2.5°
10° / 3° 2° / 0.5° 2.5° / 0.5°
5. Technical reference
Flank clearance depending on profi le
Multi-start threads
If the thread has multi-starts, calculate the helix angle with this
formula.
Tread profi le Angle (
)
Internal 15° (
)
External 10° (
)
Metric. UN
Whitworth
Trapezoidal
ACME
Buttress
Angle of insert inclination
Radial clearance Flank clearance