Quote:
Originally Posted by Lynn Eades
BSF is the fine thread as opposed to whitworth which is the coarse British thread. both have a 55 degree included angle.with a rounded valley, and flat crests, while UNC/UNF have a 60 degee included angle, with flat valleys and flat crests. Thats how I understnd it anyway.
On thread forms. A turned thread from a lathe etc, will not be as strong as a roll formed thread (which the originals probably were) because the "grain' in the metal is cut by the lathe tool, whereas the grain in the roll formed thread follows the profile of the thread.
I think many "British Motor Lorries" have used 7/8 BSF threaded wheelstuds.(often 10 stud)
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I think I'm starting to understand better, but I have seen references to BSW fine (usually with the word obsolete included) one web site is
http://www.gewinde-normen.de/en/whit...ne-thread.html
I'm with you that I wouldn't choose a cut thread for maximum strength, but I might be willing to turn the head of a rolled bolt to make a mushroom or tapered head to weld to the rim. After all, the metallurgy can be altered by the act of welding the stud in place onto the rim so this might not cause a serious loss of strength. Also, the weld is as much to stop the bolt from turnig as it is to stop it pulling through the rim.