As far as I know, there were only 2 major ones: V-1/V-2 rockets and jet engines. And neither of them are likely to need anti-tampering devices. The V-rockets blew up when they reached England, so nothing was left to ‘tamper’ with. And the jet engines were on planes – if they came down over Allied territory, it was usually in a ‘crash’, and again there wouldn’t be enough left to worry about ‘tampering’ with it.
This had confused me, too. Your explanation is clear and makes perfect sense. But do people who use it really think this, or have they just memorized “right” to describe the movement of the screw?
But they really are making right turns from their own perspective. The analogous situation would be to have it termed it a “clockwise” circuit.
Personally, I don’t think it’s “natural” for me to visualize a different physical perspective instead of using an existing common word that describes the action without that shift in perspective.
I am doubtful too. The Nazis were plenty evil, but they weren’t the type to dip a henchman’s face in acid just because he mispronounced Goebbel’s name. They were fascists, not James Bond villains. I don’t think they were going to risk a highly-trained technician’s life, just because he had too many kirschwassers at lunch and confused the directions of the threads.
Another place I have seen backwards threads is on the bolt that holds the pad on on a floor buffer. Presumably for the same reasons as the bike pedal.
The above mentioned Lada makes me think: are CC threads more common in Russia and Japan and places like that? Just seems I notice it in their products more often (which isn’t that often).
I remember my father’s car, a 1965 Chrysler Valiant, had this. There was an ‘L’ stamped on the end of the stud to remind you, but it’s something that’s hard to see at night, in pouring rain and freezing cold!
I believe it was the Brush brand auto that had an engine that turned the opposite way of most other cars. I winder if it was richer in left hand threads?
One of the attachments for our former gas grill was left-handed. I don’t remember which one; might have been the thing that attaches from the grill to the cylinder (in which case I guess it’s that way on the new one also).
IIRC, when we first noticed this, it was after a few minutes of increasing frustration!
Another way of picturing why clockwise is right-handed is that if you imagine wrapping the fingers of your right hand around the bolt, turning the nut in the direction toward your fingertips will move it in the direction of your thumb. Left-hand thread is the same way, only with the other hand.
Of course, right-hand toward your thumb is counterclockwise, but that’s for loosening. Go the other way to tighten.
Speculation: The only thing I could think of might be something like the magnetic naval mines, or time delayed bombs, air-dropped into enemy territory. You might make your screws non-standard, just to make it tougher on a bomb disposal specialist. But I don’t know if that (reverse screw) was ever actually ever done.
Another common item with left-handed threads is the nut that holds an edger blade on. Same reason as a left bike pedal.
By the way, the “lefty-loosey righty-tighty” mnemonic is useless in my opinion, because it’s not at all obvious which circular direction is meant by “left” or “right.” Anyone who doesn’t know which direction is the standard for tightening or loosening a screw isn’t going to benefit from the saying.
In that particular case, the difficulty in using that term is more obvious - viewed from the ground, a right-hand circuit is not clockwise. I’ve run into problems with people when trying to refer to something situated between us while we were facing each other. Sticking with the perspective of the moving object is a sensible way to reduce confusion.
If anyone has a small bench grinder in their garage (you know, the one that has grinding wheels on it, or maybe one is a circular wire brush), you will find that the left side wheel is held on by LH threads. This is so the resistance you put on the wheel by using it doesn’t cause the nut to back off and the wheel to come off. Many motor driven appliances are this way for the same reason.
Which begs the question, why in hell can’t the reverse threads be marked somehow so that the user KNOWS not to righty-tighty with the potential for major damage.
That only makes sense to me. Every time I get a nut that won’t break loose I worry that it’s left-threaded and the only thing I’m accomplishing is making it tighter.
Maybe I’ll start a campaign to require manufacturers to make all left threaded things in pink. That’ll fix it fer sher.
random, but our viscometers have reverse threading for the attachment spindles which are screw-threaded. We grilled the sales rep (jokingly) about this the last time when he was here and he just laughed and threw his hands up in the air.