The world has a lot of different standards for a lot of things, but I have never heard of a place with the default screw thread direction being opposite.
So does each language have a fun mnemonic?
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I like this one more.
One mnemonic is to imagine yourself opening a jar.
I use the right hand rule - ball up your fist with your thumb sticking out, and turning in the direction of your fingers curling will result in the screw going the rest your thumb points.
Right hand for right-handed threads and left hand for left-handed. If unsure, it’s most likely right-handed.
The assumption in this whole post is that it’s right-thread, since left is so uncommon.
Most common example would be a bicycle, I think - your pedals tighten on “in the same direction the wheel turns” as you look at them. So your left pedal has left-hand thread, and goes on and comes off backwards.
The effect of precession also means that you can tighten the pedals on finger tight and a good long ride will make them absolutely solid - need to bounce up and down on a spanner to loosen them.
Oh God I hate those sneaky left-thread bastards lol.
Me learning this about electromagnetism: huh, neat.
Me learning this about something I actually use in day to day life: 🤯
It’s especially helpful when you’re looking at screws (or nuts!) from the back or any other weird frame of reference.
Your door is a jar.
Is it a jar of jam or jelly?
I can easily imagine: “right is right left gets you / it left”
But not every language has the double meanings of right and left.
I remember it as right hand screw rule
We have: “Nach fest kommt ab”
The phrase “Nach fest kommt ab” is a German saying that translates to “After tight comes off” in English. It’s typically used to describe the idea that if you tighten something too much (like a screw), it will eventually break or come loose. It’s often used to remind people to not overdo things.
Yes, but that phrase does not tell you in which direction you have to turn to tighten it. So it doesn’t really answer the question?
There’s the fun police again
… nach ab kommt Arbeit
… after off work follows
Definitely nothing in Arabic AFAIK.
Not really a mnemonic in German, but I once learned how to remember of the moon was in first or third quarter by comparing the form of the crescent with the Vereinfachte Ausgangsschrift cursive letters “a” (abnehmender Mond, first quarter crescent) and “z” (zinehmender Mond, third quarter crescent). The same applies to screws watching from the top, cursive “a” is for “auf” (open) and “z” for zu (close). By reading the comments, this is somewhat the closest you get to your mnemonic.
I just have it in muscle memory to know which way soda bottle cap tightens
I think it’s fairly parochial, and sounds quite infantile to me. Growing up (uk) we just used clockwise to tighten.
Have a chat with some plumbers, builders, chippies, sparkys or engineers - assuming you are not one already. I think “leftie loosey …” is well known in the UK.
It doesn’t even bloody work, lefty tighty righty loosy is every bit as valid if the spanner is at the bottom.
Apple: User - you are holding it wrong!
The spanner is always at 12 o’clock. Either turn yourself or the spanner or your point of view to make it so and then the rule holds. The last option require imagination.
Take the piss after you have tried to thread a nut on a bolt that you cannot see and tightening it is towards you, at an angle. The nut has to cross a hack sawed thread and will try to cross thread 75% of the time unless the moon is in Venus.
It depends which bicycle pedal you’re screwing in. They have opposite threads, designed where they’re self tightening on each side.
And remember folks, pedal wrenches are for taking pedals off, not installing them. Except for that commenter with the e-bike.
Please tell Tongshen, who manufactures the popular TSDZ2 motor. The pedal keeps coming loose because they don’t do this. I keep a key on me to tighten it when it starts to loosen.
Oof, that’s some piss poor engineering right there.
Same with gas regulators that attach to the cylinders, for some reason. Oo and some hub nuts on cars
I’ve heard flammable gas uses reverse (left hand) thread to prevent cross connection. At least for welding gases in NZ; not sure about natural gas.
Acetylene does, gas lines are standard pipe.
Suppose it’s cause natural gas runs at like, 1-3 psi, while a fresh tank of acetylene is 5,000?
Least in the US
It’s also torches and everything after the regulator, which run at much lower pressure. At least in NZ
I think it might be because they’re connected and disconnected regularly so misconnection is a common problem, even with colour coding. Gas work on houses involves actually putting the fittings on pipe and is done by people who should be concentrating more on that rather than on what they’re about to weld/cut.
Bottlescrews and turnbuckles both have one end threaded in each direction.
If I remember correctly, old timey glass kerosene lanterns also have backwards threads for some reason
Gas threads and water threads are opposites to each other for safety reasons. Might be part of that thought.
Exactly! Bicycle pedals have a left-hand thread on the left-hand side and “normal” threads on the right-hand side.
Count it outer clockwise
Crank it right in?
Lefty righty, loosie tighty.
Never heard it in Polish but we generally don’t need a mnemonic to remember which side is left and which is right (except in politics).
Probably a result of turning wrenches since I was first able, but that rule, to me, feels akin to “up the stairs take you up, down the stairs take you down”.
Filing your staircase mnemonic in my mind right next to this banger for the Great Lakes.
In Dutch we have DROL, Dicht recht, open links. So close right, open left as a very strict translation. But DROL is also Dutch for turd.
Never heard of that, I just remembered from my dad that clockwise is tight and counterclockwise is loose.
Same here, except for my dad, he is clumsy as hell.
A droll factoid.
Huh, I always say links los, rechts rotsvast
Gas pipes. All gas fittings are reversed threaded. So it is virtually impossible to connect one to the other.
