"John" wrote in message
...
Jeff Wisnia wrote:
My inquiring mind just asked me why the preponderance of threaded
fasteners, jar lids and stuff have right hand threads. (Both above and
below the earth's equator. G)

Somewhere I learned that "clockwise", like the hands of a clock, comes
from the direction of rotation of the gnomon's shadow on a sundial, in
that part of the earth where sundials were first used. But I can't see a
screwy connection to that, other than it taking less time to write
clockwise than counterclockwise.


Almost all nuts have right hand thread in them.
Same with glass jars. Making lids for the jars
or bolts for the nuts with left hand thread would
be stupid, you'll never get the lid on or the bolt
started. However when RH thread is used it all fits
together nicely. Simple eh? HTH
--
SATOR AREPO TENET OPERA ROTAS
Have 5 nice days! John
******************************
--- ILN 000.000.001 ---

Think about it - you have just 'invented' the lathe.
You have just about exhausted the possibilities inherent in round shapes and
you want to go a little further. Threading rears its ugly head. The lathe
turns clockwise (as viewed from the head stock end of things - because that
is how the 'hand-held' cutting tool works). Your choice is - make the thread
right-hand and risk running into the 'chuck' or make it left hand..... or
maybe my lathe would have its drive to the right of the operator - keeping
my dominant hand away from danger?
"If I had a rocket launcher" *left* would be the direction of choice.
Regards.
Ken (Left hand dislectic machinist)