Stupid Q With A Point: Is Always Righty Tighty?

I’m trying to unscrew an aerator off a faucet. The aerator screws on (and off) from the bottom up. In such a case where one is coming up from beneath the threads, is it still righty tighty, lefty loosey? Or, is it the mirror image and the reverse? This always gets me. Similarly, I have a filter housing to a filter in a water softening system that screws up from below the threads. Per usual, I always forget which way it unscrews. It’s this “coming up from the bottom” business that throws me every time. Am I overthinking it?:confused:

Imagine you were underneath it looking up. Turning clockwise would make it go further from you, right? But if you are above it, that motion would look counter-clockwise, and would make it get closer to you. So it’s still all the same.

(Unless you are talking about left-handed threads, like on a bicycle pedal.)

Yep, I always thought in terms of closer or farther rather than tighter or looser. In this way it’s always the same …
except with those sinister threads…dah dah dahhh

Always LL&RT. always. My engineer husband told me so.

Except for some LP or gas line fittings. These will typically have a notch on the face of the nut as an indicator that it’s a left-hand thread.

Except for left handed threads. Often used in places where a right handed screw/bolt will unscrew itself. Usually found on things that spin.

You, I’m guessing know this, but I learned not that long ago. Your typical gas grill type LP tank has typical right handed threads. You can see them when you look at the valve. However, if you inside the part where you make the connection (on the tank) for a grill, there’s a set of internal, left handed threads.

I almost returned an LP heater because it used those threads and I assumed it came with the wrong connector.

Don’t confuse me. This is a basic tenet of my life. Just like measure twice, cut once. And Mr.Wrekker favorite, you can’t have too much ketchup.

You can always use the right hand rule: Make a “thumbs up” sign with your right hand. Rotate your hand so your thumb points in the direction you want the object to move. Your fingers indicate the rotation direction you need.

In the southern hemisphere, of course, you would use your left hand (just kidding).

Yeah, I was gonna ask what to do, if like me you’re a lefty? The whole world is backwards to start with. I don’t understand the ‘right hand rule’, at all.

Right and left seem slightly ambiguous when the motion is circular. I prefer clockwise and counter clockwise. Of course that doesn’t matter if the mechanic doesn’t know the threads on one side of a '67 Dodge Dart work backwards and twists off two of the lugs!

Bike pedals. It’s been a long time, but if my memory is correct, it seems like the two sides screwed in opposite directions.

And some auto wheel nuts do, or did, have right hand on one side and left hand on the other. Chrysler as I recall. Don’t know if they still do.

Still true, at least as far as the bike I assembled this past December goes.

We use propane gas and just found that out recently.

The bolt that holds the brush-whacker blade onto my weedeater’s shaft is left-handed. I had to buy a replacement once, and it cost me about ten times what a normal bolt would have.

Security bolt/screws may be left threaded. Even if you can turn them you’ll tighten them if you turn the normal direction. Light bulbs may be left threaded to deter theft.

Right/left or clockwise/counterclockwise or deisul/widdershins have to be considered from the same perspective. If you walk around a circle with the center always on your left, that’s the left hand/counterclockwise/widdershins direction.

The nut that holds the blade on a table saw is left threaded. As Joey P. says, that’s because it would tend to loosen itself when the blade spins if it were threaded the normal way.

A relevant poem, spoiled because it is NSFW

Here’s to my friend, Dead Eye Dick,
Cursed from birth with a corkscrew prick.
He spent his life in an exhaustive hunt
To find a girl with a corkscrew cunt.
When at last he found her, he about dropped dead
The goddamn thing had a left hand thread.

Always righty-tighty unless it spins, or unless you are the fucknut who owned the house before me, and twisted all the caps on the electricity wires the wrong god-damn way. (He also is the one confidently attaching 1-1/4” to 1-1/2” drain pipe by “ waterproofing” the joint with pvc glue - which in hindsight explained the de-humidifier he had in the basement - from this I have learned to never, ever buy a house from an engineer again, as they think they know shit they actually don’t. But I may be digressing here).

Most screw threads are right-handed, which means that if you are the screw, you spin clockwise (from your point of view) to move forward. Twist drills are mostly right-handed, too, and the angle is much steeper so you can see at a glance which way you’d turn it to make it travel forward. Find yourself a twist drill to hold and picture when you’re trying to figure out which way to turn something.

Looking at such a guide can help you figure out which way the male or female threads need to tun in any situation.

There are a few things that work left-handed. There are nuts and screws in situations where right-handed threads would work loose such as the left side pedal on a bicycle, or on the left side of a grinder or buffing machine. There are also objects that do this for the sake of security, such as light bulbs in some public places which would be prone to theft if they could be used at home. There are even drill bits with a lefthand thread, which you’d use trying to drill out a broken bolt, so that if it starts to turn it comes out rather than jamming itself in further.