It's 1/2"-12 Ya Dummy, Not 1/2"-13!

[hman]

I've run into a couple of Chinese products in the last year or so that had 1/2-12 threads. One explanation I've heard is that lots of mainland Chinese are superstitious. Because 13 is supposed to be an unlucky number, they've gone to 12. Urban legend? Dunno.

 

[devils4ever]

I've run into a couple of Chinese products in the last year or so that had 1/2-12 threads. One explanation I've heard is that lots of mainland Chinese are superstitious. Because 13 is supposed to be an unlucky number, they've gone to 12. Urban legend? Dunno.

I've read the same thing. Apparently, 13 is a very unlucky number in Asia, so they avoid it like the plague.

 

[Optic Eyes]

One reason for the change from 12TPI to 13TPI was that 12 reduced the root diameter too much resulting in a weak tensile strength, it was changed at the period of WW-1, I was told.

Finer threads have less depth, Single depth of thread is .866 x pitch

 

[Bi11Hudson]

This question is as much to satisfy my own curiosity as to find a legitimate answer to the original post. It has already been noted that the Chinese are quite superstitious, hence 12 v 13 TPI. Also that 12 TPI is an archaic English standard, dating back to the WW1 era.

Therefore, my question is thus: It is noted documentated that the English influence in China was very strong for many years before the arising of the current administration. Allowing for the dates involved with both sides of the debate, could that influence, combined with "adapting" existing tooling rather than starting anew, have brought about such a situation.

If there are any mainland Chinese monitoring this thread, any input from that vector would be appreciated.

.

 

[hman]

Great question! I'm quite fascinated by urban legends ... there always seems to be some grain of truth somewhere in the background, distorted though it might be over time and viewed through somebody's bias. +1 on hearing from somebody who's "been there."