The tooth type Angle is different
The main difference between British and American threads is their tooth Angle and pitch.
American thread is the standard 60 degree taper pipe thread; The inch thread is a 55 degree sealed taper pipe thread.
Different definitions
The dimensions of the inch thread shall be marked in inch; The standard system for American thread is American thread.
Different pipe thread designations
American thread is the standard 60 degree taper pipe thread; The inch thread is a 55 degree sealed taper pipe thread.
Dimensions of the same outer diameter and number of teeth
Although some British and American threads have the same outside diameter and number of teeth, they are actually completely different threads due to differences in tooth profile Angle and bite height. For example, the U.S. thread (coarse) and the imperial thread for 5/8-11 teeth both have 11 teeth, but the Angle of the thread is 60 degrees for the U.S. thread and 55 degrees for the Imperial thread. In addition, the cut height of American thread is H/8, while the cut height of British thread is H/6.
Historical background
The historical background of British and American threads is also different. The British thread is based on the British Wyeth thread standard system, and the American thread is developed by the American Willie Cyrus with reference to the British Wyeth thread standard system.
Different expressions of inch thread and American thread.
Inch thread
Standard Wyeth coarse teeth: B.S.W.
General purpose cylindrical thread
Standard Wyeth fine teeth: B.S.F.,
General purpose cylindrical thread
Whit.S additional Wyeth optional series,
General purpose cylindrical thread
Whit non-standard thread type
American thread
UNC: unified coarse thread
UNF: Unified fine thread
In summary, there are significant differences between British and American threads in terms of definition, tooth profile Angle, pipe thread designation and historical background. These differences make them have different performance and uses in specific applications.
Post time: Dec-01-2024
