On 17 June 2012 09:09, Steve Blackmore <st...@pilotltd.net> wrote: > Pipe threads are Imperial Units - BSP (British Standard Pipe) and have a > Whitworth thread form.
Whitworth thread has a 55 degree thread angle. This is better than a 60 degree angle, but harder to draw. (Whitworth calculated that 55 degrees gave the best combination of clamping force and self-locking) Most of the world's thread standards compromise to make things easier for the draughtsman and tool grinder. BA threads are 47.5 degrees. I don't know why. However BA is interesting as the sizes are mathematically derived on a series of equations. http://en.wikipedia.org/wiki/British_Association_screw_threads -- atp If you can't fix it, you don't own it. http://www.ifixit.com/Manifesto ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
