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# Unlocking Logic (Jan. 2023 Challenge Question)

Posted December 31, 2022 12:00 AM
Pathfinder Tags: challenge question

Here's a hypothetical that requires some analytical reasoning.

Which way do locks rotate: counter-clockwise, clockwise or both? Can you find determine the logic? Is there a preference for one direction or the other?

A clockwise motion to unlock a standard lock is most common, and is generally the preferable configuration. As Rixter noted, the vast majority (most estimates are ~90%) of the world is right handed and finds this turn more comfortable.

It is also more common to insert a key to unlock something than to lock it. Many residential and automotive locks will be locked by a button, twist or lever, which doesn't require a key to do. On automobiles, the driver's door will be the one unlocked most often - and at least in left-hand drive countries it better serves the driver to unlock the vehicle with a clockwise motion.

This is not a universal truth, however. Door locks are typically designed to unlock with rotation towards to opening edge of the door. This is something most humans have learned without even realizing it. But again, if all other factors are the same, the door should be designed for a right-hand dominant user.

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#1

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 1:04 AM

Locks don't usually rotate...

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#2

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 8:04 AM

Most locks, the key (and tumbler) is rotated clockwise to unlock, a direction more natural for a right-handed person. There are some that unlock in both directions, which I guess is more fair to lefties.

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#8

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 11:40 PM

I have three lockable doors in my very standard (for 1962) home. All three are turned to the right (clockwise) to lock, and to the left (counter-clockwise) to unlock.

I have a pendulum-type wall clock from Austria, another from Germany via Chile, and one made in tthe USA. All are probably between 50 and 100 years old, and I have repaired all of them, so they are currently working. The key that locks the door on every one of them must be turned counter-clockwise to lock and clockwise to unlock.

If there is any logic, it must apply differently to clock doors than to house doors.

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#15

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/30/2023 9:27 AM

This is good thinking and speaks to the most important factor: ease of use the majority of users.

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#3

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 9:51 AM

At the bakery where I buy my bagels, they put my bagel order into a bag and always turn the twist tie (the lock) in a counterclockwise direction. The employees are all women. Makes me wonder if the adoption as the standard of right hand (clockwise) tightening of bolts, screws is gender related. I always forget, when I get home and try to open my bag of bagels, that the twist tie is twisted the 'wrong' way, and I silently curse the bakery and all of its employees. Surely they must know that a twist tie should be twisted clockwise to seal the bag, and counterclockwise to unseal it. I suspect they are all radical feminists and this is their way of undermining the patriarchy. If they didn't make such good bagels I would take my business elsewhere - to somewhere that respected and upheld the screw, bolt, (and twist tie) convention.

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#5

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 12:37 PM

You could be on to something. My wife always twists those ties the wrong way (CCW)!

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#6

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 12:44 PM

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#7

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 11:03 PM

This trait is DNA related and would make an intriguing PhD Topic

(Said tongue in cheek)

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#9

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/01/2023 9:45 AM

For me (and I suspect most right handed people) it's easier to twist those ties clockwise, so, perhaps the bakery do them up counter-clockwise as a service to their customers. If you can change your mindset to thinking that it's a good thing perhaps you will be able to remember.

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#4

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

12/31/2022 10:13 AM

If the Cam at the end of the barrel

acts on two "hooks" at the ends of latches which engage with both sides of the shackle like this

Then the key must be turned clockwise to unlock.

If however "hooks" can extend right across the cam then the key can be turned either way to unlock.

Normal operation and pictures from

It looks as though that site may contain a lot of useful information.

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#10

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/01/2023 10:32 AM

Typically a mechanical lock has a stop preventing the key and cylinder from rotating to any position. Thus the key and cylinder must be able to rotate counter-clockwise and clockwise in order to get to the different mechanical states of locked and unlocked.

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#11

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/01/2023 2:04 PM

I have a padlock like the one shown. It unlocks either way.

My front door goes CW to lock, CCW to unlock.

My van's doors are opposite on opposite sides of the van.

The combination locks I've seen are usually right-left-right, but could also be opened left-right-left by a different (but related) set of numbers.

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#14

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/10/2023 7:04 AM

Depends if you are standing inside or outside. My front door is CCW to lock & CW to unlock from the outside but the opposite from the inside.

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#12

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/01/2023 7:58 PM

A dead bolt lock on a door can be configured to open in either direction when installing.A paranoid friend of mine had 3 locks on his door,with one locking counter clockwise,and the other two locking in clockwise.Anyone trying to pick all 3 locks would always have a locked door to stop them.

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#13

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/02/2023 10:16 AM

Anyone interested in locks should check out the 'lock picking lawyer' YouTube channel. The man is amazing. Here he is about to pick a US military munitions depot padlock. 3 minutes later it was open. I took his advice when I bought my bicycle lock. Bought the one he uses. If it's good enough for him...

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#16

### Re: Unlocking Logic (Jan. 2023 Challenge Question)

01/30/2023 9:45 AM

The most important apart of a lock and hasp system is the hasp.

A thief will look for the weakest link in a system.

A small portable Dremmel-type cutter wheel,and the lock itself is useless.

Locks are only meant to keep honest people out and discourage amateurs.

A local store was well alarmed at every entry point.

The thieves simply removed the cinder block in the back wall during a thunderstorm and entered.

The owner did not have occupancy sensors then,but he does now.

Insofar as picking a lock,I think a series of small magnets,in a binary coded sequence,in addition to the key would add a layer of protection.The magnets would need to be held outside of the lock in the proper orientation to open the lock.

Also magnets inside of the key could work.

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