25 Sep
2010
25 Sep
'10
1:35 p.m.
On 24/09/10 22:38, Tony Duell wrote:
The point of LH screws is not to confuse poor hackers who want to take
the thing apart. You know my views on dismantling things well enough, and
I am not going to hinder others from doing the same :-)
You use LH scres in places where RH screw would tend to be loosened by
the movement of the parts concerned. Like that 5.25" disk drive I
mentioned. Such cases are not common, but they do exist.
As an (odd-topic) aseide, the Sony EIAJ reel-to-reel video recorders have
a metal disk mounted on a spidle by a nut and lockwasher. The head beam
fits onto the disk 9and is held down by 2 screws), the head tips then go
round a slot beteen the 2 stationary drum parts. That nut really should
be left-handed (it isn't) becuase it's naturally loosened by the
mocvement of the parts,and if it comes loose, the head beam goes askew
and the head tips get shattered as they hit the drum. Don't ask how I
found this out...
-tony
I've seen left-handed taps and dies on sale.
And of course it's easy to
cut a left-hand thread on a lathe. But I have never seen LH nuts an bolts
listed by any company in the UK. But I've not seriously looked for them.
PTS (or someone like them) could probably make them up if you really
wanted them...
Though given that the standard is right-handed, I'd file left-handed
under "use only if you want to screw with peoples' minds". Pun not
intended but worth a grin regardless :)